# Deck Sagging and Rotting



## SFLman (Feb 22, 2016)

We have a deck which was constructed in 2009 and is 10" high.  The planks are Trex.  This is the view looking East. 







There are two unique areas which the deck covers.  The first is cement pad which goes around the pool, and the second is that part of the deck which extends out over the yard.  The sagging below shows where the cement is and where yard is.  The higher part on the right is where the cement is. 






You can see below that the joists which run East and West, and are perpendicular to the Trex planks are holding up pretty well.  But the joists which run North and South, have really rotted.  

There is landscaping fabric on the ground under the joists that go over the yard.    






The Trex was not installed correctly, there is supposed to be a 1/4 inch gap between planks.  I've communicated with the company on how to fix that.  It involves using a circular saw to create a gap between the planks. 

One of the joists which runs East West has significant damage.


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## SFLman (Feb 22, 2016)

I don't know what to make of these grey stains.  The wood feels strong, so I think it's just dirt stains.  But it may be the beginnings of rot.  I just don't know wood.  I've tried to clean these stains, and while some dirt comes off,  the color is definitely in the wood. 






Here is a picture of a wooden post siting on the concrete pad.  It has a galvanized base:






There were 4 joists here.  Three in particular are in really bad shape.  What I can see of the one at the top looks good.  






Other than dynamite, does anyone have any general ideas about what should be done?


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## nealtw (Feb 22, 2016)

The better looking joists my be treated lumber, if not they should be upgraded.
My guess is the the beam ended up 3" away from where the plans called for it and 2 untreated timbers were added to make the joists reach.
If the grey stains can be removed with a pressure washer without removing any wood, then you might think they are treated.


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## havasu (Feb 22, 2016)

That last pic looks like that one support is sitting in the mud.


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## nealtw (Feb 22, 2016)

havasu said:


> That last pic looks like that one support is sitting in the mud.



You are missing half of what you can see there.
There are 2 timbers in hangers on short posts.
2 more timbers nailed to the first 2.
We can see galvanized hangers and hanger nails.
But we also see some common or bright nails that have rusted.
We can also see the start of the problem when we look at the top boards there is a joint right above the timber that has almost rotted away, so water could get in but it had now where to go, so that timber never had a chance to dry out.


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## Sparky617 (Feb 23, 2016)

The gray streaks are just staining from the water coming off of the deck between the gaps in the TREX.  I can see the same thing on the underside of my deck, though mine is all PT wood not TREX.

I'm not a fan of ground level decks.  The 2x material used for the floor joists is most likely all PT wood but it is not rated for ground contact.  A floor joist that is well off the ground will be able to dry out between rain storms.  When it sits on the ground it will soak up water and rot prematurely even if pressure treated.

I would opt for either a paver patio or a stamped concrete patio instead of deck if I'm on grade.  Higher cost but little to no maintenance over the years.


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## joecaption (Feb 23, 2016)

I'm with Sparky on this one.
A few other issues some of that older Trex had a recall because of all the failures.
http://topclassactions.com/lawsuit-...trex-decking-class-action-lawsuit-settlement/
Any composite decking needs air flow under it.
Joist spacing can not be more then 16".
There's been many post on this site and any DIY site showing all the damage to joist from ground level decks because of no air flow under them.


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## nealtw (Feb 23, 2016)

SFLman said:


> I don't know what to make of these grey stains.  The wood feels strong, so I think it's just dirt stains.  But it may be the beginnings of rot.  I just don't know wood.  I've tried to clean these stains, and while some dirt comes off,  the color is definitely in the wood.
> 
> 
> 
> ...



I think we all agree, it was built wrong, but there is lots of life left in much of the framing. And it is fixable if that is what you want to do.


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## joecaption (Feb 23, 2016)

That gray just looks like whatever they used to tint the composite is washing out.
One of the many issues with that old Trex.


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## SFLman (Feb 23, 2016)

Thanks for all the replies.  Joe, I read about that mold and coloring class action lawsuit.  Your comment about the grey coloring seems on target.  I guess that the mold or algae is washing down onto the joists as well.  

Anyway, to be more clear, here is a picture showing where the deck is resting on the ground: 






You can see one area (under the 3rd red arrow) that is still up.  I hired a guy to do a quick repair in the beginning of 2014.  He lifted up that joist and put a stone under the joist.  At the time, that was the lowest dip in the deck. 

I'm almost for sure not going to do this repair by myself, but I want to have some good ideas before I get a carpenter over here. 

I guess a complete repair would look like this:

1)   Take up the planks over the four North South joists that run right at the edge of the concrete pad.  

2)  Tear out the rotten NS joists, and replace them.  Reconnect the East West joists to the NS joists.  

Put the planks back on and call it a day. 

If I was going to do this myself, or if I hire someone, there would be a need to use some kind a jack.  Maybe even several being operated at the same time, now that I think about it.  

Am I thinking right here?  I'm already trying to think of any short cuts!


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## nealtw (Feb 23, 2016)

1 Remove enough of the decking to work on full length of beam.
2.Remove the hangers from the joists on the rotted side of the beam.
3 remove the two rotted members.
4 Inspect the other beam members replace if needed.
5 Cut the ends of the joists to allow for 3 plys of beam.
6 paint all cut ends and any wood with signs of rot or everything you can see with copper treatment.
7 build an new "two"ply beam with underground rated wood. "underground rated wood looks just like regular but has hundreds of knife cuts so the treatment gets deeper in the wood".
8 add 8" blocks to one side of the new 2 ply beam. "each end and in the middle"
9 Bolt the new beam to the old beam with HDG 5/8 thru bolts and washers at the area of the blocks.
10. Replace the hangers with HDG nails.
If two men can't lift and block the joist back in position for working on them an old bumper jack will work fine.
I put the blocks in between for two reason 1 cut away rotted ends. 2 allow water to drain between the 2 beams.
If the ends are worse that that, cut off the rot and sister on new as long as you can 5-6 ft.
11 before we had treated wood we put strips of tar paper on top of joists so water did not sit on the top of the joists and I think I would do that here. 3" for singles  5" for doubles


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## SFLman (Feb 23, 2016)

This is just the sort of suggestion I'm looking for   


Of course, I have a couple ?uestions:

1)  If I'm going to chop off the ends of the East West joists, I wouldn't have to remove the hangers (your step #2 above) which are attached to a rotted member of the old 4 ply North West beam.  I'll just cut off the ends of the EW joists and toss the hangers in the trash.  

Do I have that right?

2)  I get the whole concept of creating a new North South beam (in addition to repairing the old one).  I'm just not sure if the new 8" blocks will be, according to your plan, sitting on the yard or sitting on the concrete.  

FYI, only one member of the 4 ply North South beam is good.  In the photo below, it looks like two of them are still good, but only the top two inches of the second joist dpwn is good, and it has rotted the rest of the way downward.  I think the topmost member in the photo is still good, but once all three bad plys are taken out, it might reveal that there's some damage.


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## nealtw (Feb 24, 2016)

SFLman said:


> This is just the sort of suggestion I'm looking for
> 
> 
> Of course, I have a couple ?uestions:
> ...



1) The bottom of the hangers are 3" deep, so if you don't want to cut them, you will need to remove them.
2) You are removing 2 rotten plys and replacing them and bolting them to the other 2 ply beam with blocks for spacers between the 2 beams.
So just like the old set up where everything was nailed together except now water will be able to run between the old beam and the new one.
We can see one joint in the top decking was right over the second timber and the water had no where to go.
As far as more damage goes, just keep digging until you have it all and replace.
If one ply of the other beam has to be removed you can sawsall the nails that hold them together or just pull the hanger nails on that side and change them both.
http://www.homedepot.com/p/Estwing-12-in-Pro-Claw-Nail-Puller-PC300G/202033613

You will be cutting only 1 1/2 to 1 5/8" off the joists.

What you have now is 4 timbers nailed together, I am suggesting 2  2 ply beams bolted together with a 1 1/2" space between them


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## SFLman (Feb 24, 2016)

I think I've got your idea.  

In the drawing below, the old North South beam is shown in gray with a gray post.  The purple area is empty, to allow water to flow down.  The orange shows a post, and a new 2 ply green beam, with one ply nailed to the other ply.   

Do I have the location of the the bolt correct?


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## nealtw (Feb 24, 2016)

Almost, the block will just be 1 1/2 thick so both green beams in your picture go thru and will be the same length as the old one
When we bolt the ledger to the house we put a bolt about every 32" so maybe more bolts and blocks than I said before.
If there is a footing below those posts and below this second beam you could block up under the new beam too.

The picture is incised lumber and it should be tagged for below ground use.
Hot dipped galvanized nails, hangers, bolts, nuts washers. The treatment will eat untreated steal


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## slownsteady (Feb 24, 2016)

From what I'm reading here and other threads, you might consider raising the section of the deck that's over the dirt. A two-level deck has disadvantages but it might hold up better with some circulation below it....just a thought.


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## nealtw (Feb 24, 2016)

slownsteady said:


> From what I'm reading here and other threads, you might consider raising the section of the deck that's over the dirt. A two-level deck has disadvantages but it might hold up better with some circulation below it....just a thought.



This is a big expensive deck, I think he can get another ten or fifteen years out of it, with a good repair. Other issues may show up in time but most anything can be fixed cheaper than replacing.


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## SFLman (Feb 25, 2016)

The cement pad lines up with the 2nd ply:







1st ply is definitely damaged !






In the next few days, I will get more planks up so I can see how the deck is supported out in the yard.  I've never been able to see that because there's a North South Beam which blocks my view.  Also, not every East West joist is on the ground.  I need to put pavers underneath of them.


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## nealtw (Feb 25, 2016)

Where you have the blade stuck in there, change them both, there is no sense in leaving cancer in there when you are this close.
Where you put the red line, it looks like there is one on top the other, or??
On the pool end you would expect to see a beam below the joists with the joists cantilevered over it to pool edge.
If you haven't got enough scrape laying around just cut a bunch of untreated 2x4 blocks to hold stuff up while you work on it.
Since you have fabric down there I would get a shop vac and clean  the leaves out of the area


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## nealtw (Feb 26, 2016)

http://www.homedepot.com/p/1-qt-Copper-Green-Brown-Wood-Preservative-CB-QTS/202688831

Tar paper.


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## SFLman (Feb 29, 2016)

Not that it matters much, but I now know how the deck out in the yard is supported:







An 8" post supports two joists and sits on some kind of board.






But the real reason for my post tonight is that I've come up against a nasty problem which I have no idea of how to address.  Some of the screws I'm trying to take out are snapping on me.  I'm trying to get the planks up which are over the beam that needs to be replaced.  Two different types of screws were used to fasten down the planks.  One type has a larger head and has held up fairly well.  But as I move South, I'm encountering another type of screw with a smaller head.  Here is one of each kind:   






These little-headed screws are mostly the type used from where I'm at going south.   So far, I've snapped 1/3 of them.  Then they just spin.  1/3 will come out, and the rest are frozen.   I"m going to put more liquid wrench on the frozen ones, and they may snap once I start to get them up!  I need to get about 230 screws up to get the 5 rows of planks up which are over the beam.  Almost all of the screws are the weak small headed kind.    

Any ideas??  If the bottom half of these screws are in the joist, I won't be able to put a new screw in that that hole.  If they are snapping just under the head, I can twist them out with a pliers after lifting up the plank.


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## nealtw (Feb 29, 2016)

I have broke those putting them in too.
I would leave that problem solving until after you have seen the wood, if you are changing beams out it won't matter as much.
New screw will just go down beside the old ones. Or maybe you can juggle some boards so the holes no longer line up.


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## bud16415 (Mar 1, 2016)

The reclaimed deck I took down to build mine 75% of the screws snapped off taking the old deck apart. I didn&#8217;t bother even trying to get them off I ether snapped them off flush or hammered them in flush. Like Neal said the new screws will run right in beside the old ones and hold fine. If you find a real problem one just angle it a smidgen when you start it. Much better than seeing open holes in the decking. Switching the boards is also a good idea of Neal&#8217;s.


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## SFLman (Mar 13, 2016)

I have neglected these pages for the past two weeks, but for a good reason.  






Remember the old newspaper comic "What's the Diff?"






I advertised the 20 year old hot tub on CL free to anyone who would pick it up.  18 people responded.  After a number of near misses and complications, and people veering off on me (Hello?  Hello?  Do you still want this??)  the hot tub is gone.  






While we were moving it, much of the wooden framework broke up like mush.  If it had not been for the insulation, we would not have been able to move it.  I can barely believe that this tub was designed for outdoor use.  The framework was clearly not pressure treated and had sucked up water like a sponge.  Luckily, the guy still wanted the tub!  We rolled it out on 4 4" pvc pipes with a 2X8 1/4 plywood sheet under the mushy part rolling over the pipes.  After that dude was up on the trailer I was in such a good mood I gave each of the three guys twenny bucks!






I'm going to take a few days to regroup, coz that's how I roll, and then I'll be back asking more questions.  Thanks!


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## SFLman (Mar 26, 2016)

Over the past few days I have spent time cutting between the planks to create and increase the gaps.  Trex calls this a Kerf cut, and they sent me a .pdf file on how to do this.  To some degree, the reason the deck is rotting and sagging is because the person who installed the deck failed to leave gaps between the planks.  My ability to fix this problem with the saw may dictate how I move forward with the entire fix of this deck.

In the picture below, you can see a dark spot on the deck.  It rained here a two days ago, and there was a puddle there all the next day.  Not good!  This area of the deck is where the hot tub was. 






The .pdf file says that you need to modify a rip fence to hold the saw in place while you push the saw along and make the gap cuts.  I tried to make a few cuts without a fence, and it did not turn out well.  Maybe you can see the uneven cuts between these two planks.






After ordering the Bosch WD7RIP fence, which has a wider "stem" than fences for other brands such as Dewalt, I could see that the modification suggested in the .pdf file was not possible.  They want you to flatten out the blade of the fence, and I did not have the ability to either bend or grind down the curved bottom lip.  

But I did come up with a fix, and I can testify that it works.   I used a masonry bit to drill two holes. 






I then cut and bent an ordinary piece of thin aluminum.  I then tore out a hole with a pair of needle nose pliers and slid the aluminum "blade" onto the rip fence and attached it with bolts.


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## SFLman (Mar 26, 2016)

Here is a view of the circular saw with the new fence.  The original WD7RIP fence is upside down.  






BTW: I'm using a rather thick blade in the circular saw, and it's working out better than the thin blade which came with the saw.  Trex does make a blade and I bought one for $30.00 or so, but I have not yet used it.  They advertise that the blade they make will prevent melting the Trex.  The blade I'm using is made for plywood.  I got two bundled together at HD for 8 bucks.  The company advises against using a thick blade like the one I'm using.  So far I've encountered no problems.

I plan on doing the Kerf cuts for a few more days, and then finally get back to figuring out what is the ultimate solution to this whole mess.


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## nealtw (Mar 27, 2016)

https://www.jccayer.com/Dewalt-DW35.../p/7848/gmc/?gclid=CK3Fl7zI4csCFRVsfgodeHAPwQ

All the tool brands make blades like this pretty much all purpose.


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## SFLman (Apr 3, 2016)

Here's a floor jack which starts out at 3.5 inches.  I will need one of these, unless anyone has a better suggestion.  Kinda pricey at $51.00 but I will be glad to have it. 

http://www.sears.com/craftsman-2-1-2-ton-floor-jack-low-profile/p-00950165000P

Next question: should I worry about trying to match the screws that were used in 2009 ?  I think these are them: 

http://www.homedepot.com/p/Grip-Rite-9-x-2-1-2-in-Coarse-Gray-Internal-Square-Torque-Drive-Composite-Deck-Screw-5-lb-Pack-N212CSG5/202755197

I guess the question is, will it be noticeable if I use a different style of screw?

The last issue: instead of using the kerf cut I'm toying with the idea of removing a row or two of planks, and then shifting the other rows to create gaps.  I could use this shifting technique on the rows that don't go around the pool.  Would this work ?  

After all this I've finally learned what the Kerf of a blade is.  They make some blades awfully wide.  I won't be buying one of these: 

http://www.infinitytools.com/8-Flat-Top-Blade-24T-5_8-Arbor-250-Kerf/productinfo/080-250/


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## nealtw (Apr 4, 2016)

Do a little digging in grandpas garage, and old car jack or a pick will work for a lot of weight.
If you rework the deck for proper spacing, you may end up with water landing on beams again with no where to go.
I am not sure it was a spacing problem it was just that the water was on the beam with nowhere to get out.


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## slownsteady (Apr 4, 2016)

I'll bet no one is going to look at the screw heads on your deck except for you and anybody (family friends and neighbors) who are familiar with your deck saga (well, maybe us too; but we're prolly not coming by to visit). But you, on the other hand, will probably notice the difference every time you step onto it. match them if you can, but don't make yourself crazy...and don't match them to the ones that are breaking.


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## nealtw (Apr 4, 2016)

Because you want to use the same holes and some screws pulled thru I would just use the green or beige deck screws.


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## SFLman (Apr 8, 2016)

Thanks for the advice on the screws.  Neal, do you remember who makes the ones you recommend?  

Here is the plan I have come up with to fix the deck, I'd appreciate hearing your opinions.  

The first picture below is to review.  This is a drawing of what we currently have going on under the planks, which did not last.  The red numbers 1 2 3 4 are on the North South beam which is composed of four joists.  The purple squares are 4 X 4 inch posts.  The yellow East West joists are 16 inches apart.  The drawing is not to scale.  In real life, the posts are 6 feet apart along the beam.






The first step in the repair will be to cut off any East West joists over the yard which have rot, and to remove North South joists 1 & 2.  The newly cut EW joists will have to be temporarily propped up at the correct height. 






The next step will be to remove the remaining half of the beam, and cut back the EW joists which are over the cement.  Some of these have a little rot right at the edge where they were fastened to the beam.  These will be cut the same.  I don't know how much of these joists I'm going to cut off, but I'm guessing maybe 1 foot.  As these joists are cut, they will be propped up as well. 






Whereas before we had 1 beam made of 4 joists, now two separate beams will be constructed, with both sitting on the concrete.  These narrow beams won't hold water like the old bigger one did.  Additionally, these beams will have roofing paper tacked on them.


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## SFLman (Apr 8, 2016)

For the next step, short EW joists will be fastened between the two new beams.  






Then Sister joists, shown in orange below, will be fastened to the EW joists over the yard.  In the drawing the three original cut joists over the yard are the same length.  When I really do this, they will be cut according how much rot is on that particular joist, so they will be different lengths.  More board will be run to continue the original joist so that the plank screws will have something to bite into. The completed new structure as I envision it is shown below:






Here is a picture of the new structure with one gray 5 inch wide Trex plank on it. 






I'm leaving out quite a few details, but this is generally what I think should be done.  

Is there a much better solution?  Cheaper?  Faster?   Am I doing too much?  Or do I pretty much have it?


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## nealtw (Apr 8, 2016)

Just a few thoughts to go with that. The space between beams 2 and 3 should have the odd block between them just to hold everything together, we wouldn't want to separate decks moving independently.
Hopefully the east west joists will only need to be cut back enough the get the new beam in. If some do have to be cut back more, I would do a long sister for lots of strength. Something around three feet of overlap  and the fill in the missing space so the screw holes in the decking will still work..


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## slownsteady (Apr 8, 2016)

You mentioned that the new beams will be sitting on the concrete. I hope that is just a quick way to explain it and that those beams will not be in any contact with concrete. make sure you have drainage (and air) underneath those boards.
How are you fastening down the (purple) posts?


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## SFLman (Apr 8, 2016)

Posts will not be sitting right on the concrete.  

Do you know the specific names of the hardware pictured?   






I will be imitating the work that was done before, except that there will be two main beams instead of one.  

I'm guessing I shouldn't try to re-use any of the galvanized hangers?


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## nealtw (Apr 8, 2016)

SFLman said:


> For the next step, short EW joists will be fastened between the two new beams.
> 
> 
> 
> ...



Green a beige deck screws a available where you buy treated lumber 

Don't forget some end cut treatment for any cuts you make in treated lumber.

Two points.
1. the blocks between beams 2 & 3 just nail a 2x4 on flat to #3 every 3 or 4 ft and then nail the next to that and then the next. It will be one with a space between.
2  The old beams were hung on the the post, if it is easier you can just place a short block under the beam, no real need for the hanger.

But yes I think you have it. When we sister to a joist we expect the next joist to do some of the work so if you are doing a bunch in a row, add to the length of the sisters and lots of nails or screws


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## SFLman (Apr 8, 2016)

Your suggestion #2 is really sharp and you just made the project considerably easier.  Thank you. :beer:


I don't follow suggestion #1.  Considering how good suggestion #2 was, I want to be sure to understand 



> the blocks between beams 2 & 3 just nail a 2x4 on flat to #3 every 3 or 4 ft and then nail the next to that and then the next. It will be one with a space between.



I think your saying that I should drop the idea of having EW joists drawn in yellow above between beams 12 and 34.  Instead I should just have a 1.5 inch space.   In the drawing below I've put two green 2X4s.  They would be nailed into joist 2.  Joist 3, the left half of beam 34. would be nailed to the 2X4s, and joist 4 would be nailed to joist 3.  Beam 34 would still rest on short blocks as you suggested the beams should. 






Below is a rodent's eye view of joist 2 in yellow with a green 2X4 nailed to it, and the joist sitting on a small purple 4X4 post : 






The screw holes in the planks are fully 3 inches apart, so there will be one row of planks covering over the 1.5 inch gap.  Do I have your idea right?


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## SFLman (Apr 9, 2016)

Well, this would be even easier.  

Here I cut off just a few inches off of the EW joists over the cement, and then create 1 beam just 2 joists wide which sits on 4X4 purple posts.  Then I extend the EW joists over the yard to the new beam.






What say you?


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## nealtw (Apr 11, 2016)

Your picture with the green 2x4 between the beams is what I had in mind.
In your first photo in post #1 it is clear that the gap in boards was over the beam and the space provided by the 2x4s will allow water to drain thru.

I am not sure that just the one double beam will be strong enough to carry the weight from both sides. I would hate to have you do all this and find the deck sagging under it's own weight.


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## SFLman (Apr 12, 2016)

Well, as usual you've made a comment which has caused me to do more digging.  (It's good for me!) 

Over the concrete, the EW joists are propped up with metal feet.  The feet are not only screwed to the wood, they are screwed into the concrete.   Here are two different EW joists. The camera is pointed toward the house in both pictures. 







In the picture below, the joist terminates at the East side of the pool.  






Also, I believe that those EW joists which go all the way to the house, in other words, do not terminate into the side of the pool, were cut to rest on the concrete.   

It's really the first bit of carpentry that I've seen which I really admire.  Near the skimmer below, the there's an EW joist just to the left of a light grey line.






I took a picture holding the camera over the skimmer lid aiming toward the house, and the joist is cut to rest on the ground, plus it has a metal bracket screwed into it, which is also screwed into the concrete.






The joist you see on the left in the picture also rests on the ground, and makes the west wall of a box that goes around the skimmer. 

With this new information would you now think that the "One 2 joist beam" design with I drew above would be adequate?


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## nealtw (Apr 12, 2016)

Well that is a neat trick that I never thought of.
If these are the same joists that you intend to stretch I would think yes, you could even use that trick to stiffen things up.
My only other question is, did they give any special arrangement to get the water out from under there. If there is a slope on the old concrete deck it should be running right to where your beams are may be a little trench to let it flow out?


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## SFLman (Apr 12, 2016)

While I was doing the kerf cutting a while ago down at the south end of the deck near the house, I could see sunlight reflected in a small amount of water.  I took it to mean that the planks are so tightly placed along side each other that evaporation is slow. 

As for drainage in the West area of the deck between the house and the pool, maybe there is a way for the water to drain down onto the lip of the pool.   

I have thought it over, and I'm going to hire this fix out.  But at least I have a plan and a good understanding of the main problem.  I will post pics of the repair as it progresses.   Thanks again!


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## nealtw (Apr 12, 2016)

You would really like water to go someplace not just sit there but you can't do much about it now.
Each contractor may have a different approach to the fix but you have enough what ifs to ask to get what you want.


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## SFLman (May 27, 2016)

Well, I tried to find a company to fix the deck, but it did not work out, so I'm doing it myself.  This is much, much easier than I thought it would be.   Additionally it has occurred to me that I can fix the deck in 10 foot sections, and the southernmost twenty feet can even be fixed next year since it is in pretty good shape.   

Here is how things look with the most rotten part removed, and a new 2 joist beam put in.  I'm using the GC (ground contact) wood from HD.  I was told that they are phasing out their Weathershield wood entirely.  It is still on the shelves but not for long at the store I was in.     






The new hangers aren't holding hardly any weight at all.  The metal feet drilled into the concrete supporting the joists support the weight.  Even so, of course, I put in hangers and connected the East West joists over the cement part to the new beam. 






But I do have a question now that I'm in the middle of it.  

The part of the deck that is over the yard has sunk quite a little.  I could do it, but I don't want to jack the East West joists over the yard up any higher.  Instead, I'd like to "cheat" the sister joists as shown below: 






The piece of wood shown clamped to the original joist in the picture above is a 2X4, and that is not what I will actually use.  I will actually use a 2X6, but all of my 2X6's were too long to fit in there to photograph.  

I will run a 2X4 between the original joist and the new beam for the plank screws to bite into.  I intend to screw it into the new sister joint.  Would I need to cut a wooden pad for the plank screws?  Something like the photo below?


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## nealtw (May 27, 2016)

Your sisters should match the originals, 2x8 or 2x10 ?
Cut a bunch of tappers and wedge the joists back up the straight.
I am not understanding the Vs cut out of the beam, that really does weaken it.
Your taper to level the joist in the last picture works if you are replacing missing wood.
http://www.deckmagazine.com/engineering/rules-for-drilling-and-notching-deck-framing_o.aspx


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## SFLman (May 27, 2016)

I don't know where I got the idea that 2X6's were sufficient for sister joists.  If I were to use the original size joist, I guess I'd have to notch it to clear the cement pad.   I've got maybe thirty bucks worth of cut 2X6's which can't be returned.  I suppose I could take it to the re-store and start over.  On a scale of 0 to 10 how essential would you say it is to use the same size joist? 

The V's cut in the bottom allow for drainage.  As I said above, for the time being, it's just not bearing hardly any weight.  The metal feet screwed into the concrete are holding up the EW joists over the concrete.   Are you advising me to take it out and start over?  The V's are 3 inches wide.  More that three times the limit in the chart you linked. 

The East West Joists which go over the yard terminate in an unknown way into a North South joist which sits on the ground in the yard.  I can't see how they are fastened together.  I'm afraid if I elevate the EW joists which go over the yard much more, something is going to snap. Here are two photos to show what I'm talking about.  This is the view East away from the house.   







This is the view West toward the house.  






To review, I am not talking about the joist termination at the edge of the deck.  That looks like this:


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## nealtw (May 27, 2016)

To be clear the notches they talked about in that article would not get past an engineer, they just say no.
That being said , you are so close to the concrete I would just put a treated shim under each side of the V cut.
The photos you have under the joist are showing blocking.
When joist are more than 7 feet long they have solid blocking between them to stop any roll over with warp or twisting.
Your deck originally went over the concrete, so there should be no reason you can't get it back to where it was.
So if you set up to shim them back up, you set them up and wedge all at the same time, tap one just a little then the next and the next and back and forth until you have them all back up.
Lay a chunk of wood under each joist and cut a wedge that fits between the joist and that chunk of wood.

Understanding the floor joist.
A joist gets it's strength by the compression of the fibers on the top 1" and the tension of the fibers in the bottom 1".
To gather more strength for a longer span or a heavier load we want more distance between the top and bottom.
So with that we can see the notch in the bottom is a problem for strength and a change to a 2x6 will be just like a notch and would provide a weak spot.

As you already are against the eight ball with so many sisters in close area anything else that weakens the structure is just bad news.


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## SFLman (May 27, 2016)

I'm thinking the pictures were unclear.

Only two feet of the ten foot beam I've installed is off the cement.  I cut a GC 4X4 post to go under that part in addition to putting in a hanger.  






The other eight feet is sitting on the concrete. 











The cement has pebbles in it, so I probably didn't need to cut any damn triangles anyway.


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## nealtw (May 27, 2016)

Check the picture of the knife cuts in post#15 and make sure you are not being lied to about underground treatment, check with other lumber yards.
Having the beam sitting on the concrete isn't the best, I would have cut it down by a have inch so it could be raised giving space below but as is it will likely last the better part of 10 years
I see you used bolts on the beam, when you sister go with nails and lots of them like 4 every 6".


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## joecaption (May 28, 2016)

Your using the wrong sized hanger on that beam, and it's one of the most important connections.
That spacer you put in there is useless for anything but a temporary block to hold it in place.
With the end grain exposed at the top and the bottom going to be sitting on top of that concrete unable dry out it will fail.


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## SFLman (May 28, 2016)

Nealtw - little by little I have wedged up the joists so that the sister joists will not have to be "cheated" up.  You certainly stopped me from getting creative in a bad way! 

Regarding how to connect sister joists, as best as I can tell there's continued vigorous debate as to whether one should use nails, screws, carriage or hex bolts.  If you have a link to a source I will read it.  


Joe - I will look at replacing the hanger on there.  I thought the label said the hanger I  bought was for 2X6's and 2X8's.  When I google the big number on the receipt 044315271908 I keep coming up with a taller 6.75 inch double hanger.  The one I have is 5 inches tall.

Regarding the pad, I will cut a new one going with the grain.  That's a good thing for me to learn.  I should have something reliable at that spot in case the structure sags in the future.

All little blocks shown in my pics will be removed, they are temporary.   

If anyone knows how many feet I should overlap on my sister joists I'd appreciate hearing.  I'm still debating whether to use my 2X6's, or, as Neal has advised, to sister with 2X8's to match what is there.  I still can't remember who told me 2X6's were acceptable to use as sisters!  I know I did not play lone horseman on that point.


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## nealtw (May 28, 2016)

Screws do not have the same shear as the nails, you can find charts for that, so even more if you want to go that way.
You read the bit about notching, in effect you would be notching out 2' x what ever length you have cut away.

As I explained earlier about joists the top is under compression and the bottom is in tension so that big notch moves that tension from the bottom of the 2x8 to the 2x6, at some point of loading the 2x8 will split length ways starting at the notch.
Same with using bolts, you are moving the compression and tension to the center of the wood in the joist, either could split on the drill hole.
As for length, as long as you can get in there and still be able to nail it.
Might be a good time to rent a nail gun.
After all that is said the better plan would be to put in new footers and a beam to carry those joists and short blocks in between the beams.

And good job lifting them.


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## SFLman (May 29, 2016)

And I now remember who it was who told me I could sister 2X6's onto the 2X8's.

I went to HD and asked to speak with someone experienced in deck construction.  I explained that I wanted to create a new North South beam of 2X6's which would sit on top of several 4X4 inch pads.  So, the 2X6 inch sisters would connect up to my new beam of two 2X6 inch joists.  The person who I talked to said that would be fine. 

A day later I got to measuring here and there and I discovered that I could just use 2X8's, sitting on the ground.  I learned about "ground contact" wood and decided to create the new beam with two 2X8's sitting on the ground. It seemed to me more stable than 2X6's sitting on 4X4 pads.  I then got concerned about drainage, and that's when I cut the triangles. 

Neal, I have read in many places that if you are going to sister on a joist, you need 3 feet of overlap.  You don't agree with that in this case?  

I'm strongly considering removing the two 2X8 inch beams with the triangles I've installed.


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## nealtw (May 29, 2016)

Yes if you have one broken joist you would sister on a 6 ft piece giving you 3 ft of overlap.
As you have a multitude of joins, I would go all the way back as far as I could, just think of doing it again in a year or two, this is a time for over kill.
The one you have that is really short I would cut that square and install one between the two longer ones and then hang shorty off that and then a short up to the beam.
If you change out that beam, rip 1/2" off them so they will not sit on the concrete, you should be able to find plastic shims in the door dept and then just shim them to the concrete.
I do not believe that wood is treated for underground use.
You could use that beam for filler pieces after you have sistered to replace what was cut away.


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## SFLman (May 30, 2016)

That souinds like a good idea for dealing with that short one.  I have drawn the fix you suggested as I understand it.   The original joists are in yellow, the new sisters in orange, and the fix you've suggested to deal with the really short one in green.  (The sisters will in reality overlap more going further back.) 

Wouldn't I need two 2X8's going perpendicular to the short one?  






I don't know if you can have two hangers on opposite sides of a single 2X8, so I've drawn two.


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## nealtw (May 30, 2016)

Yes a double is required but then the joist on each side should be doubled too, which you can't do. I should have said that.


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## SFLman (May 31, 2016)

I've taken up planks down at the South end.  I won't be replacing the beam in this area since it has not yet rotted.  I suppose I could put some tar paper on it to help it survive longer than it otherwise would.  I will replace the beam   when it deteriorates more some future year.  

I now know what the original carpenter did when he constructed the beam.  The bottom three joists of the beam are 2X6's.  The bottom two are in a double hanger, and go into the 4X4 inch posts.  Then, the next 2X6 up is toenailed onto those.  Then he toenailed a 2X8 onto the 3rd joist.  The 2X8 extends down to just below the concrete pad.  






So the East West 2X8's over the yard are hung onto that 2X8 inch beam joist. 






If the 4X4 inch posts had been just a little taller, he could have just hung the EW 2X8 inch joists onto the bottom two joists.  That beam would not have been 4 joists wide, and then it probably would not have rotted.  I'll never know what he was thinking.  It's tempting to believe that I'm seeing something that was improvised due to some sort of disorganization or miscalculation.


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## nealtw (May 31, 2016)

He could have hung the 2x8 joist off the 2x6 beam, but he would have had to notch the joists for the concrete, I suspect he was afraid the 2x6 beam would sag and wanted the height of the 2x8 for strength and get away from the concrete below.


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## SFLman (Jun 1, 2016)

What he did just seems improvised.  From my viewpoint, I need to replace 20 feet of his handy work!   

BTW: as I have taken out plank screws, quite a few of them would not come up because they would just spin.  When I finally got the plank up, I would see that the wood around the screw had rotted or split.  These are screw holes in joists that I will be keeping!  There have also been plenty of stubborn screws which I got out by using the crow bar, so there's more screw holes which are compromised. 

I'm tempted to fill the cracks and screw holes with a glue or something.  Good idea?  Not worth it?


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## nealtw (Jun 1, 2016)

Just a sliver of wood stuck in the hole will help, the very old trick was a wooden match stick. Or a screw a little longer than was there.


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## MrMiz (Jun 9, 2016)

If you have a few extra minutes go to Fine Home buildings website and watch the Ultimate Deck Build 2015. It's several videos that goes over all the steps they took and why building a deck. I know it doesn't solve your problem, but I know some of the steps they took actually explains why your deck failed. Granted their solutions are probably the most expensive way to fix it, but you might get some ideas to help.
I hope it does help. I hate redoing other peoples work but it happens all the time, and to be honest with you I don't really blame the original carpenters anymore. Sometimes their ideas just don't work out or they don't educate themselves as best they can, and 99% of people don't want to pay for educated long lasting work. I even catch myself sometimes trying to justify paying somebody less qualified to do the work because it's considerably cheaper.

I would have liked to have seen the ground dug out and sloped away at least 6 inches deep. Then filled with local cheapest rock to provide airflow and drainage. Then I would have minimum covered the tops of the joists with tar paper. If the money allowed it something with a sticky back, but that stuff is costly. So that is what I would have done to start. Now with the damage done the cheapest thing to do would be to do just that but only where the damage is ... shovel out the dirt where you can, dump in the rock, and replace the rot then cover the tops. This might get you by for another 10 to 15 years maybe. That is what I think would be the absolute cheapest. If it was mine however I agree with the others I would probably start over. It really sucks but I think a correctly built deck should last you at least 25 to 35 years depending on you climate and since I didn't see a lot of mold I don't think your climate is overly moldy.

My 2 cents.


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## SFLman (Jun 10, 2016)

Thanks for your response, you've laid out much to consider.  I will mark down another vote for tar paper.  Here is a product named Quick-Fix Protecto Wrap which I purchased at HD.  I was about to put it down on the 25' of original beam which I did not replace, but I second guessed myself.  I became concerned that it might make the rot accelerate instead of slow.  The Protecto Wrap came in a 30' roll and cost around $25.00 if I remember.  I also decided not to use it because I became concerned that it might harm the lizards.  The warnings about the chemicals that the materials contain were very strongly worded.

Here is how the deck looks today.  







I had to rip off 3/4" from the sisters to clear the cement pad.  It would have almost been very nearly the same thing to just sister 2X6's onto the original 2X8's, but that's all good.  








I have screwed in 2X4s onto the sister joists so that the screws holding down the planks will have something to bite into.  I used two 3/8" bolts and PL400 glue to secure the joists & sisters together.  I will be using 10 D nails in addition to that.  

I've unfortunately noticed that the deck is coming apart in other areas. Here is a picture of the original 4-joist beam, 25' of which I'm not replacing since it looks OK for the moment.  You can see that the 2X8 and the 2X6 which are toe nailed together at the top of the picture are separated from the two 2X6's at the bottom of the picture which are secured to the post.  

Should I use a big bolt to pull this mess back together?  Hammer in new nails maybe?  Or just ignore this?


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## SFLman (Jun 10, 2016)

Here is another area where I can look down between the boards and see the the 10 Nails are not holding.  Should I jam a brace of some sort under it?  Bolt?  Leave it alone and hope for the best?   







The air circulation must be improved to reduce the rate of failure.  I want to rip a tiny bit off of the planks that I have up.  I am considering renting a table saw with a good vacuum system.  I tried ripping them while they were screwed down, as Trex recommended, butthe results were a bit inconsistent, and it was very messy.

And I will be sure to check out the Ultimate Deck Build video you recommended.  Thanks


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## MrMiz (Jun 10, 2016)

I would put one or 2 bolts in just don't go over board, and don't OVER tighten. Your not trying to take the warp out your just trying to prevent future warping. If you attempt to take the warp out you just might end up putting more pressure in places you can't see. just enough where you feel like it will keep it from completely separating. I would still consider putting the tar/protecto wrap on. If it's going to be under the deck boards your lizards should be safe.... but you know them better than I do. It's probably only toxic if the eat/bath in it.

Other than that it looks good. Again focus on the fact that you adding life to the deck. Your not making it last forever just giving it another 10 to 15 years hopefully.


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## nealtw (Jun 10, 2016)

I would bolt the beam but don't close the gap, then you have the shear strength and left the gap open just put a wedge beside the bolt.


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## nealtw (Jun 10, 2016)

I would also add nails or screws to the sisters. You are trying to make them one so they bend and warp or whatever together.
If you think about just bending the joint at some point one piece will split at the line of the bolts. 3 nails 6 to 8" OC.
With the bolts you have shortened the joint to the distance between the bolts


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## SFLman (Jun 10, 2016)

I think I follow you but want to check.  Below are 4 "lines" of 3 10D nails.  The sister joist is yellow, the bolts are red.  The original joist which was cut back is brown.  Each line of 3 nails is 6 to 8 inches from the others.  Correct?  






Also, again I want to be sure, you are talking about the nail pattern in each of the 14 sister joists, correct?  You are not saying I should put nails in the places that are coming apart.  For that I need a minimal amount of large bolts, and don't over tighten.


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## nealtw (Jun 10, 2016)

SFLman said:


> I think I follow you but want to check.  Below are 4 "lines" of 3 10D nails.  The sister joist is yellow, the bolts are red.  The original joist which was cut back is brown.  Each line of 3 nails is 6 to 8 inches from the others.  Correct?
> 
> 
> 
> ...



Yes and yes:


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## SFLman (Jun 10, 2016)

Well, that's some pretty good exercise!  12 more to go.


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## nealtw (Jun 14, 2016)

SFLman said:


> Well, that's some pretty good exercise!  12 more to go.



I would just space the top boards and cut the last one to fit.


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## SFLman (Jun 16, 2016)

That's a good idea and I would prefer to do that.  I've noticed that some of the planks are bowed, and I don't know how they are going to get along with the table saw I'm going to rent.  

If you look at the plank labeled AON you can see a pretty dramatic curve to the left at the far end of the plank.  That's not a trick of the camera, that dude is considerably bowed!






But there are some irregularities which pose problems when considering the idea of ripping one down and shifting the other planks over.  The whole deck, it seems to me, could not be done that way, or it would be really difficult.  

There are three big lamps bolted into the deck, here is one of them.  I would probably have to call in an electrician before moving it.






A few feet away from the lamp, there is also an irregular notch cut out of the bottom of this plank.  So this plank looks to me like it's not movable.  






The planks which go around the posts which hold up the hot tub cover have holes cut in them.  Not impossible to fix, but difficult.


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## SFLman (Jun 16, 2016)

But I could, by taking out just 6 more boards create a clean rectangle in which to do your plan.  It would be 13 planks across and stretch the entire length of the deck.  The rectangle is outlined in yellow:






Questions:  How odd is this rectangle going to look in relationship to the rest of the decK?  

And, these joists are not in the greatest shape.  Is putting a bunch of new screw holes in these joists going to be a problem?


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## nealtw (Jun 16, 2016)

To start, I do not understand the notch in pictures 2 and 3.

Just a few thought on cutting the boards.
1. what is it you are trying to do by cutting them, could just put them back and drill some holes between to allow water to run thru.
2. table saws are great for cutting sheet stock not so much for what you are doing, not impossible but needs some experience.
3. not that hard to jig up a skill saw, type of jig would depend on how comfortable you are with the saw.


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## nealtw (Jun 16, 2016)

SFLman said:


> But I could, by taking out just 6 more boards create a clean rectangle in which to do your plan.  It would be 13 planks across and stretch the entire length of the deck.  The rectangle is outlined in yellow:
> 
> 
> 
> ...



You will want to brag to all your friends about the work you did, this would just give them a chance for them to ask.:


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## SFLman (Jun 16, 2016)

1)  The planks have almost no space between them in the area where the rotting occurred.  But, it is not necessarily why the rotting happened.  Even so, the reason for slicing down the planks a little is to promote evaporation.  

2)  It's just $50 to rent a table saw.  I think I'm going to end up trying it. 

3)  I have looked up ways to make a circular saw into a table saw, where you screw the saw to a big board and turn it upside down and use a zip tie on the trigger and the on/off button of a power strip to turn the saw on and off.  I think renting is the better way to go.  

If slicing a little off of each plank doesn't work, I may use your idea of ripping one down and just scooting them over.  However, since they aren't going to be wedged together, and since some of them are bent, it may end up being difficult to get the planks to lay nicely.


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## nealtw (Jun 17, 2016)

SFLman said:


> 1)  The planks have almost no space between them in the area where the rotting occurred.  But, it is not necessarily why the rotting happened.  Even so, the reason for slicing down the planks a little is to promote evaporation.
> 
> 2)  It's just $50 to rent a table saw.  I think I'm going to end up trying it.
> 
> ...



I said build a jig not a table saw.
Your choice. 
cutting a warped piece on the table saw
Stand 8 ft away to try to support a 14 ft board, attempt to hold it tight to the fence as you cut it, the other end flops down causing a big curve over the table.
So now you need a table of sorts to catch the other end, a second fence of sorts to hold it tight to the first fence.
Or you build a jig out of a 2x10 and a couple chunks of 2x4.

As your boards were tight the space will have to be exactly what you cut off.
Put a spacer between the fixed piece and the loose piece 
Where the curve is to hard to straighten by hand  a 2x4 screwed to the side of the joist can be used as a lever to push it in tight to the spacer.

Constant measuring open space that is left to make sure everything is straight and will finish as required, some adjustment of the space may be needed.


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## nealtw (Jun 17, 2016)

The jig.
drill a hole in about the center in the front and back of the table on the skill saw.
Lay a 2x8 or 2x10 on the side of the deck, just about where your table is sitting in that last photo
Lay a deck board on top of the 2x10 and line that up with the out side edge
Lay a 2x4 beside that and screw it down to the 2x10
These pieces only needs to be about 3 ft long but longer is fine too.
Wire or zip tie the blade guard up out of the way.
Remove the deck board.
Set the saw on the 2x4 so the the larger part of the table is over the 2x4 and the blade is over the 2x10, set the blade depth so it doesn't quit touch the wood below.
If you are going to use 3" nail for a spacer, place one in front of the saw and one behind the saw tight to the 2x4.
Place a level or something straight against both nails.
Adjust the saw so the teeth of the blade are just touching that straight edge check both front and back of the blade and screw the saw down, double check the teeth are right.
Remove level and the 2 spacer nails.
Lift and lock the blade out of the way and replace the deck board along side the 2x4.
You have that little fence that attaches to the saw that you tried to use before
Set the in so it captures the other side of the deck board, not to tight.
Now you can slide the board thru and get a feel for how it will work adjust as required
Zip tie the trigger on the saw and lower the blade so it is cutting into the 2x10 about 1/8".
If you have a serge protector with a switch on it, that would be good to plug the saw in to.

You will have to come up with a plan too hold this in place as it will want to slide.
*Remember*, you will be looking at the wrong end of the saw when you are feeding the board in


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## SFLman (Jun 20, 2016)

I've pretty much convinced myself not to cut down the planks. 

The joists are in fairly good condition, and the rotting was caused by bad structure design, not by the planks being too close together.  

In however many years, whenever it's necessary, the part over the lawn can be cut away, and the part over the cement could be left for a little longer.  

I'll think it over for a day or two and then maybe I'll close this project out.


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## nealtw (Jun 20, 2016)

That was my first thought, if you do that and end up with a joint over the beam, maybe caulking the crack for that one may save a problem


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## SFLman (Jul 22, 2016)

Here is the finished product, and I'm very satisfied with the results.  It feels sturdy to walk on.  







I estimate I saved around $1,500 by doing the job myself, but I don't know because I never got an estimate.  






There are other parts of the deck that need to be worked on, but they can wait until next year.

A few warts: 

I did not end up with the planks looking as nicely as the original carpenter.  I can live with a few irregularities.   






Some of the screws which I removed broke off at the neck, and when I could I removed them then and there.  But some were stubborn, so I left them in.   Here I can see that a tiny bit of a screw was sticking out from one of the planks.  Each time I moved the plank, I scraped the ones below it.  Maybe I will try to sand down these drag marks some day.


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## nealtw (Jul 22, 2016)

:thbup::thbup:
It looks great from where you started. Good job.


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## SFLman (Jul 22, 2016)

In the end I did decide to use the 6 inch wide Protecto Wrap on the 20 feet of new beam that I installed, plus the 25 feet of old original beam which had not rotted.











The Protecto Wrap is curious stuff.  If you are careless and touch the black side to another part of the black side, it will stick like cement.  You have to cut that part away and throw it out.  To other things, it will hold either strongly or lightly, or even not at all.  To the wood it held moderately.  

I decided that the biggest risk to the lizards would be that they might stick to it if they happened to walk on it.  So I cut it and pressed it against the wood to minimize that risk.  The white side of the wrap isn't sticky at all.    






Neal, I used nails as spacers to help line up the boards.  I would not have thought to do that, but the plan you posted for making a jig employs that tactic.


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## nealtw (Jul 22, 2016)

The peel and stick is good idea but a little expensive, right beside it at the store you could have bought a primer, brush on or spray. More often I would have just stapled it where it wrapped down the side.
That should give a lot more life to the beam, I like it.


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## slownsteady (Jul 22, 2016)

You learned a lot and got a good, usable deck out of it. You should feel good about it.:thbup:


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## SFLman (Jul 26, 2016)

Thanks Slow!  I definitely feel very good about the deck!  When I used to look out the window, I felt like I had no good options.  But now, it's the complete opposite.  I fixed what was wrong, and I know that I can deal with future problems myself.  This website and everyone responding really helped me.  I would not have been able to do it without the support of Neal and everyone else.


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