# Digging down along my foundation



## swimmer_spe (Jun 4, 2017)

I plan to dig down about a foot below grade to put in large pavers. Along the foundation of my house, is there anything that doing this will cause damage to? Also, there are 2 posts that support an overhang that is over my porch. Will digging down next to those posts potentially cause any issues?


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## nealtw (Jun 4, 2017)

The big question is depth of the bottom of the footing. If you have a deep basement, you could expect the bottom of the footing about 1 ft below the top of the floor. 
If you have a walk out basement you would expect the bottom of the footing to be right at the frost depth for your area.

Just a guess but for your area it may be 4 ft or more and you don't want to cheat that.


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## swimmer_spe (Jun 4, 2017)

nealtw said:


> The big question is depth of the bottom of the footing. If you have a deep basement, you could expect the bottom of the footing about 1 ft below the top of the floor.
> If you have a walk out basement you would expect the bottom of the footing to be right at the frost depth for your area.
> 
> Just a guess but for your area it may be 4 ft or more and you don't want to cheat that.



I guess I should have said that I have a full basement and from the bottom of the window to the floor is at least 4 feet. I am not digging that far down.


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## nealtw (Jun 4, 2017)

swimmer_spe said:


> I guess I should have said that I have a full basement and from the bottom of the window to the floor is at least 4 feet. I am not digging that far down.



The only other problem I can think of is we always like the landscape to slope away from the house, so planning on drainage or at least considering it would be a good idea. But other than those two issues no problem.

You did mention a posts, driving a steel pin down to find the footing might be a good idea.


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> The only other problem I can think of is we always like the landscape to slope away from the house, so planning on drainage or at least considering it would be a good idea. But other than those two issues no problem.
> 
> You did mention a posts, driving a steel pin down to find the footing might be a good idea.



I plan to have it a V as it is the walkway between my house and my garage and I do not want water going the wrong way.

Why find the footing if I am only going a foot down?


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## nealtw (Jun 5, 2017)

A post put in when the house was built may have the footing at the same depth but it could be just as likely to have the footing at min depth for frost.
If the post was installed after the house was built you can be sure it will be at min depth for frost.


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> A post put in when the house was built may have the footing at the same depth but it could be just as likely to have the footing at min depth for frost.
> If the post was installed after the house was built you can be sure it will be at min depth for frost.



What would be that minimum depth? I aam in Northern Ontario where we get winter.


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## nealtw (Jun 5, 2017)

Try this site, you can put in postal code.
http://www.plumbinghelp.ca/frost-line-depth-north-america/


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> Try this site, you can put in postal code.
> http://www.plumbinghelp.ca/frost-line-depth-north-america/



I am near the 2000 line. What does that number mean?


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## nealtw (Jun 5, 2017)

Our depth is around 20 inches and that chart shows 500 so my guess is 2000 equals 2 meters. 79 inches? Phone your local building dept. at city hall.


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> Our depth is around 20 inches and that chart shows 500 so my guess is 2000 equals 2 meters. 79 inches? Phone your local building dept. at city hall.



2m is believable.

Time to get a 2+ foot rod and see if I am safe to dig down 1 foot around those posts.


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## nealtw (Jun 5, 2017)

swimmer_spe said:


> 2m is believable.
> 
> Time to get a 2+ foot rod and see if I am safe to dig down 1 foot around those posts.



Been thinking about it. When they dig for foundation work they dig out 5 ft for working space. So if the posts are original to the house and are withing five feet, a good chance that they are as deep as the house


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> Been thinking about it. When they dig for foundation work they dig out 5 ft for working space. So if the posts are original to the house and are withing five feet, a good chance that they are as deep as the house



The problem is, my house is the only one with one. That tells me it is not original to the house.


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## nealtw (Jun 5, 2017)

swimmer_spe said:


> The problem is, my house is the only one with one. That tells me it is not original to the house.



Then did they do a footing or just dig a hole and dump concrete in? 
Maybe put the pin on an angle and see if it will go under it.

You would need 10 ft to hit the post at 6 ft deep @ 45*

Are you sure you want to dig down a foot.:hide:


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> Then did they do a footing or just dig a hole and dump concrete in?
> Maybe put the pin on an angle and see if it will go under it.
> 
> You would need 10 ft to hit the post at 6 ft deep @ 45*
> ...



A foot is a guesstimation. Basically I am digging down to the same depth they dug for my garage. Then I will fill with gravel. Then I will put the large pavers on top.


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## nealtw (Jun 5, 2017)

swimmer_spe said:


> A foot is a guesstimation. Basically I am digging down to the same depth they dug for my garage. Then I will fill with gravel. Then I will put the large pavers on top.



If you are filling it back to the same level, you will not have changed anything.
You still measure from the new finished height.

It is just a matter of how long it stays below 0* C for the frost to reach the depth below a chunk of concrete. And how much moisture is under that concrete.


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> If you are filling it back to the same level, you will not have changed anything.
> You still measure from the new finished height.
> 
> It is just a matter of how long it stays below 0* C for the frost to reach the depth below a chunk of concrete. And how much moisture is under that concrete.



I know that. I am looking at the hole beside the man door and the grass beside my house and I want to get that all down to the same level and then lay down gravel and then put down 12x24 pavers so that it is nice to walk on.

Lets say you faced that. What would you do?


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## nealtw (Jun 5, 2017)

swimmer_spe said:


> I know that. I am looking at the hole beside the man door and the grass beside my house and I want to get that all down to the same level and then lay down gravel and then put down 12x24 pavers so that it is nice to walk on.
> 
> Lets say you faced that. What would you do?



Not a fair question. I have been known to gamble from time to time.

The frost depth is only reached so many times in a givin period of time but the climate is changing, more or less frost who knows.

I think I would poke around and see if I could figure it out. We don't know that they followed code at the time. If they cheated by a foot or two you could be buying trouble. If you find that it is a full depth I might take the chance. 

It is a matter of understanding the odds. Maybe you can find out how often the frost gets close to depth in the area.


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> Not a fair question. I have been known to gamble from time to time.
> 
> The frost depth is only reached so many times in a givin period of time but the climate is changing, more or less frost who knows.
> 
> ...



I meant about whether to just fill in the current hole with dirt and go down a few inches, or to dig out the rest of the dirt and fill with gravel.


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## nealtw (Jun 5, 2017)

swimmer_spe said:


> I meant about whether to just fill in the current hole with dirt and go down a few inches, or to dig out the rest of the dirt and fill with gravel.



Either way if you come back to the same level, the measurement stays the same
If you have xft now and dig it all out and fill it with gravel, you still have xft.

:trophy: I am sure we will come to an understanding soon. 
Will you be at or near the same level as it is now when you are done?


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> Either way if you come back to the same level, the measurement stays the same
> If you have xft now and dig it all out and fill it with gravel, you still have xft.
> 
> :trophy: I am sure we will come to an understanding soon.
> Will you be at or near the same level as it is now when you are done?



Yes, the overall grading of the area will not change. So, do I just dig out the high side, pit it to the low side, keep the grading for drainage. OR, do I dig the fill out, put gravel in there, keep the grading for drainage?


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## nealtw (Jun 5, 2017)

swimmer_spe said:


> Yes, the overall grading of the area will not change. So, do I just dig out the high side, pit it to the low side, keep the grading for drainage. OR, do I dig the fill out, put gravel in there, keep the grading for drainage?



Yeah I thought of that too. You want gravel for a base for the block but the water can then go down into the gravel instead of running off with the landscaped slope.

If you have a place where you could drain the trench you could add a perforated pipe and waterproof the bottom of the trench..

You could water proof between the gravel and sand layer so water runs off from there.

Or just do a concrete sidewalk.


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> Yeah I thought of that too. You want gravel for a base for the block but the water can then go down into the gravel instead of running off with the landscaped slope.
> 
> If you have a place where you could drain the trench you could add a perforated pipe and waterproof the bottom of the trench..
> 
> ...



Next year, I plan to repave or use pavers for my whole driveway next year. This is a more of a stop gape for winter.


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## nealtw (Jun 5, 2017)

swimmer_spe said:


> Next year, I plan to repave or use pavers for my whole driveway next year. This is a more of a stop gape for winter.



will the driveway have a slope down to the road.. Do you have a yard drain to a city storm drain. 

Your yard is fairly level isn't it?


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> will the driveway have a slope down to the road.. Do you have a yard drain to a city storm drain.
> 
> Your yard is fairly level isn't it?



The yard i fairly level. The front of the garage is about the middle of the yard and the high point. The driveway slopes to the curb, and the walkway will slope the opposite way.

No yard drain.


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## nealtw (Jun 5, 2017)

swimmer_spe said:


> The yard i fairly level. The front of the garage is about the middle of the yard and the high point. The driveway slopes to the curb, and the walkway will slope the opposite way.
> 
> No yard drain.



My fear is of a trench filled with gravel sloped toward the house will transport water back to the house. We don't want solve one problem and create a flooded basement.

How about, digging the trench on a slope down to the point center between the house and garage and water proof that with a couple layers of heavy poly (PLASTIC) to move the water to the that center spot before inters the dirt.


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## swimmer_spe (Jun 5, 2017)

nealtw said:


> My fear is of a trench filled with gravel sloped toward the house will transport water back to the house. We don't want solve one problem and create a flooded basement.
> 
> How about, digging the trench on a slope down to the point center between the house and garage and water proof that with a couple layers of heavy poly (PLASTIC) to move the water to the that center spot before inters the dirt.



So, dig the berm on a V, sloping towards the garage? I could do that.

For the plastic, does it need to be heavy duty?

I agree, the last thing I need is a flooded basement.


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## nealtw (Jun 6, 2017)

swimmer_spe said:


> So, dig the berm on a V, sloping towards the garage? I could do that.
> 
> For the plastic, does it need to be heavy duty?
> 
> I agree, the last thing I need is a flooded basement.



Yeah if it is going to hold water and stretch into shape and not cut with the gravel.
Perhaps a layer of sand just below and just above it to protect it.
6 mil is what they put under concrete in the basement.


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## swimmer_spe (Jun 7, 2017)

This is the area. The post is the black thing. There are 2 on this side.


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## nealtw (Jun 7, 2017)

Funny, that is not the picture I had in my head. So do you have gutters and down spouts on the house and will you be adding them to the garage?

Before you built the garage and you had a rain, the water was spread out over the area, now half of that water is landing between the house and the garage.


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## swimmer_spe (Jun 7, 2017)

nealtw said:


> Funny, that is not the picture I had in my head. So do you have gutters and down spouts on the house and will you be adding them to the garage?
> 
> Before you built the garage and you had a rain, the water was spread out over the area, now half of that water is landing between the house and the garage.



The garage will get eves and a downspout. The house has a mansard roof, so putting eves are not easy.

Now you see why I want to put in a V.

So, that grassy area is about a foot higher than the dirt beside it. What would you suggest?


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## nealtw (Jun 7, 2017)

I would think about digging the V like you have said, with poly from up the house foundation to up the garage foundation, sloped one way or the other with a perforated pipe with pipes up to catch the downspouts. 
Run that pipe to open area front or back yard to lower area or a french drain. Then you will have no water against the foundation in that area.


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## swimmer_spe (Jun 7, 2017)

nealtw said:


> I would think about digging the V like you have said, with poly from up the house foundation to up the garage foundation, sloped one way or the other with a perforated pipe with pipes up to catch the downspouts.
> Run that pipe to open area front or back yard to lower area or a french drain. Then you will have no water against the foundation in that area.



There are no downspouts yet. When there will be, they will not be in that area. They will be at the other end of the Garage.


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## nealtw (Jun 7, 2017)

swimmer_spe said:


> There are no downspouts yet. When there will be, they will not be in that area. They will be at the other end of the Garage.



So the area won't get more water than it did before the garage but the garage may block the path of the water and the gravel will hold the water and more will work it's way to the bottom of the foundation.

If your new height will be at or close to the entry into the garage, the new level will be a raised area so maybe do you gravel and then the poly and sand so water will be directed to the other end of the garage away from the house.


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## swimmer_spe (Jun 7, 2017)

Now, about the grassy area, do I dig that down all the way to the point that the rest of the trench is? Or do I just get rid of the grass, and then do as you suggested?


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## nealtw (Jun 7, 2017)

swimmer_spe said:


> Now, about the grassy area, do I dig that down all the way to the point that the rest of the trench is? Or do I just get rid of the grass, and then do as you suggested?



You are suppose to prep the area by removing soil and compacting gravel but if you don't disturb the soil under the grass, I would leave it unless the soil is particularly loose, if that makes sense.


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## swimmer_spe (Jun 7, 2017)

nealtw said:


> You are suppose to prep the area by removing soil and compacting gravel but if you don't disturb the soil under the grass, I would leave it unless the soil is particularly loose, if that makes sense.



It does. The soil I do remove to make the profile, can I simply pit it in th trench to build it up so I don't need so much gravel? I will tamp it down.


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## slownsteady (Jun 10, 2017)

I think Neal may be over-thinking this a bit. But the idea of a perf pipe is a good one. Dig down a foot...maybe 16 inches and lay the pipe right down the middle. Use a pipe sock or landscape cloth to prevent clogging. Then lay in the gravel to cover the pipe (about 1 inch below the finished grade). The last inch should be paver sand or concrete dust or something similar. level that and lay in your pavers. As long as you're not laying soil against the wood on either side, the finished grade can be wherever you want it. The only concern is where the perf pipe will end. Do you want it open to the ground in either direction or would you want to continue the trench to a convenient location?
As far as the footers are concerned; if they are visible at the surface, you will have to cut the pavers around them. If they are at least as deep as the depth of the pavers, just add the same sand and lay the pavers flush up against the post (again, you may have to cut pavers to make them fit within the pattern you choose).
One last thought: polymeric sand is great as a finish sand between the pavers, but it sheds water rather than letting it soak in. So you may have more surface runoff than expected. OTOH, regular sand will allow water to seep into the soil and gravel, but given the location between buildings, you may not want that to happen, even though the perf pipe is there. It's above my pay grade to make that decision for you.


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## swimmer_spe (Jun 10, 2017)

slownsteady said:


> I think Neal may be over-thinking this a bit. But the idea of a perf pipe is a good one. Dig down a foot...maybe 16 inches and lay the pipe right down the middle. Use a pipe sock or landscape cloth to prevent clogging. Then lay in the gravel to cover the pipe (about 1 inch below the finished grade). The last inch should be paver sand or concrete dust or something similar. level that and lay in your pavers. As long as you're not laying soil against the wood on either side, the finished grade can be wherever you want it. The only concern is where the perf pipe will end. Do you want it open to the ground in either direction or would you want to continue the trench to a convenient location?
> As far as the footers are concerned; if they are visible at the surface, you will have to cut the pavers around them. If they are at least as deep as the depth of the pavers, just add the same sand and lay the pavers flush up against the post (again, you may have to cut pavers to make them fit within the pattern you choose).
> One last thought: polymeric sand is great as a finish sand between the pavers, but it sheds water rather than letting it soak in. So you may have more surface runoff than expected. OTOH, regular sand will allow water to seep into the soil and gravel, but given the location between buildings, you may not want that to happen, even though the perf pipe is there. It's above my pay grade to make that decision for you.




I am using 12''x24'' patio stones. 

Digging down for a drain is a good idea. Where should it go? How far beyond the walkway should I lay it?

The footers? Do you meant he footings? The ones for the house are at least 4 feet down. Not an issue.


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## slownsteady (Jun 11, 2017)

12x24x? The length and width of the pavers is really not a concern, but how thick are they? If they are two inches thick, then that has to be accounted for in determining whether they will collide with your footings. I'm not at all concerned with how deep the footings go because whatever you expose at the surface, you will be filling back in with gravel and sand. But if the top of the footing is exposed...or only one inch below the surface,,,then your pavers will have to detour around them. Or you will have to cut them to fit, Or use decorative gravel to fill the gap or something like that.


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## swimmer_spe (Jun 11, 2017)

slownsteady said:


> 12x24x? The length and width of the pavers is really not a concern, but how thick are they? If they are two inches thick, then that has to be accounted for in determining whether they will collide with your footings. I'm not at all concerned with how deep the footings go because whatever you expose at the surface, you will be filling back in with gravel and sand. But if the top of the footing is exposed...or only one inch below the surface,,,then your pavers will have to detour around them. Or you will have to cut them to fit, Or use decorative gravel to fill the gap or something like that.



The footing is 4 feet below grade. These are no more than 2 inches thick. Depth and cutting are not an issue.


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## slownsteady (Jun 11, 2017)

Okay. So the top of the footings for those posts is four feet below ground. No concrete is visible. No problem.


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## nealtw (Jun 12, 2017)

slownsteady said:


> Okay. So the top of the footings for those posts is four feet below ground. No concrete is visible. No problem.



As frost depth is 80" and top of footing is 48", water getting to the footing could be a problem. So over thinking says a few dollars in poly is just an attempt.

But what ever is done there should be a mark placed on the foundation  and a level line on the post so in a cold spell the height of the post can be monitored and any sign of movement can be address by cutting the post and fix that problem the following spring.


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## swimmer_spe (Aug 1, 2017)

UPDATE

I am not digging around the posts for the overhang of the roof. I have discovered the posts are supported only by this:

http://www.decksgo.com/deck-foundations.html
It looks kinda like the ground anchor spike.

So, in short, I am not going to dig right to them. Instead, for this year, I will only dig enough to put in one row off the large patio stones.

I plan to get a professional in to redo the driveway and stairs. I will have them deal with this new issue as well.


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## slownsteady (Aug 7, 2017)

If this is temporary, and a pro will be doing the area next year, don't even bother with laying gravel or trenching. Just enough sand to give you an even base for the pavers.


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## swimmer_spe (Aug 7, 2017)

slownsteady said:


> If this is temporary, and a pro will be doing the area next year, don't even bother with laying gravel or trenching. Just enough sand to give you an even base for the pavers.



A ditch was left from the construction of the foundation. I filled it in with gravel, laid the pavers on top, and put some sand in the cracks. They slope away from the garage.


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