# help i want to finish my attic



## beastmode986 (Oct 2, 2011)

i want to finish my attic with my dad the only opening to get in there is like 4 ft long and 2 or 3 ft wide it has alot of potential i know id have to open up the opening more i would also need to reinforce it and put up dry wall and insulate it but what else and what could this cost i can get pics sorry if this is the wrong section im new my dad says it will be like 6 grand but he dosent know much about home improvement i know i would also need to run electricity up to the attic also


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## nealtw (Oct 2, 2011)

If the roof has been built with manufactured trusses the answer is "no not wirth the expence" If the roof was hand framed with rafters and ceiling joists you may be able to do it but it is still expencive. The house would have to be checked from the foundation all the way up to figure out how to carry the extra weight and how to bring that weight to the foundation. The furnace may not be big enough for the extra rooms and the electical panel will want to be checked. You will have to find ways to get hot air ducts and return air thru the house. Inlarging the stair case adding floor joists and re-designing roof structure should be done by an engineer.


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## BigChuck (Oct 2, 2011)

Sounds like a major project, I'm moving into a home with a full attic and might need to upgrade the carpet.  As we all know, more space is so valuable!


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## BridgeMan (Oct 12, 2011)

Sorry, but I have to disagree with nealtw on his requiring a check of the foundation to see if it is adequate.  First of all, the nominal increase in load caused by finishing an attic is miniscule compared to the overall load placed on a structure's footings.  Attic insulation, sheetrock and flooring weight would make up only a very small fraction of the total load (dead and live) that all residential footings are designed by code to support.

Furthermore, it's simply not practical to dig down to each and every footing on any given structure, and then make an accurate determination as to its strength and internal reinforcement (unless a person has LOTS of money to spend on the effort, or knows a licensed engineer and/or testing lab willing to work for free.  Where I come from, they all want to charge for their services).


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## nealtw (Oct 12, 2011)

I don't know Bridgeman: The structure would be changed with new bearing poinst for stairs, dormers and whatever, I would want to know where that weight is going, what type of foundation I have and the condition it is in. The biggest problem is the center bearing wall which is often a curb on a min. footing or worse, a string of double 2x8s sitting on posts and 12x12 footings. We have drilled lots of holes in basement floors to determan the size of footing. 
Ok so lets say the foundation looks good, How do we get the new weight from the attic to the foundation? As you know the easiest way to add stairs to the inside and still support the floor would be to use double floor joists. Those doubles need to be supported with double studs and blocking all the way to the foundation. 
How about a dormer that finds it's self right above a window, don't we want to look at the size of the header over that window?
Maybe it would be better to build and just to see what cracks appear!


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## BridgeMan (Oct 16, 2011)

nealtw said:


> I don't know Bridgeman: The structure would be changed with new bearing poinst for stairs, dormers and whatever, I would want to know where that weight is going, what type of foundation I have and the condition it is in. . . . . . .We have drilled lots of holes in basement floors to determan the size of footing.



OK, nealtw, I'll play along.  So you've "drilled lots of holes in basement floors," in order to accomplish exactly what?  In case you didn't know, most residential foundation footings extend outside of basement walls as well as inside of them (or do you also drill holes, typically 10' deep, through the walls' backfill to get down to and verify the presence of external footings?).  And the practice of drilling random holes in basement floors does little, if anything, to determine the actual load-bearing capability of footings beneath those floors.  An accurate determination of concrete strength is required, along with knowing the amount and size of any steel reinforcement present.  As a minimum, concrete core samples need to be taken and broken by a testing lab to determine compressive strength, and the entire footing needs to be exposed to enable using a Pachometer or other means to determine the size and location of rebar.  

So perhaps you could explain exactly what your basement floor hole-drilling accomplishes, other than considerably weakening those floors while verifying that footings are present.

To explain my earlier comments regarding the small amount of increased loads placed on a typical residential building undergoing an attic remodel, I've crunched some numbers:

For the sake of argument, let's say a typical, yet simple remodel will include a walled area approximately 20' by 20', with 8' ceilings, no internal walls.  The total dead load weight of drywall (including fasteners, texturing and paint) and wall studs/top and bottom plates and fasteners for such a room comes out to 3000 pounds (rounded up from an actual number of 2932 lb.), based on 1/2" drywall at 2 lb./s.f., and seasoned Doug fir density of 32 lb./c.f.   Dividing that total by the total number of studs for such a room (I used 70, based on 16" spacing and triple-stud corners, doubler at a door), results in slightly less than 43 pounds additional compressive load on each stud.  And this amount, less any distribution factors for more wall members below, could be expected to carry on down through the lower level walls and into the foundation.  Using the Doug fir, No. 1 stud-grade are good for 1250 psi, resulting in (total of 1250 x 5.25 sq. in.) each stud being capable of resisting a total load of 6563 pounds.  The 43 pounds we're adding to each stud having a total working capacity of more than 3 tons of resisting force, doesn't really amount to much.  Doing the arithmetic, actually just a bit more than 6/10 of 1% of total stud capacity.

Feel free to correct me if you think I'm wrong, but I think the foregoing numbers are good.  And I agree with you that anyone attempting to do a major remodel of any kind, needs to verify what's there as best he/she can, making every effort possible to make sure the existing structure isn't being compromised.  Please keep in mind that I am not a design engineer, so I suspect astute designers may question some of my reasoning, having more experience with load-distribution theory.


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## MMM (Oct 16, 2011)

I agree with Bridgeman. Going through and calculating all loads and verifying footings is the text book correct way of doing it but for what he is trying to accomplish here, it certainly is not requited.

Having done this on many projects with engineers, 9 out of 10 times we come to the same conclusion that no extra reinforcement is necessary unless there is something seriously wrong.

Good luck!


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## nealtw (Oct 16, 2011)

I like what MMM said " unless there is something seriously wrong". Questions do have to be asked before we can assume a good foundation and footings. If the exterior foundation is 8" concrete sitting on a good footing I wouldn't have a concern, but if there is a center curb on footing bearing wall that will be asked to carry 1/2 the added weight. The extra weight does not get distributed evenly on that wall as loads are moved with staircases and such. If you drill a hole near that center wall you can determin how deep that wall is, the deeper the better as it would be able to disperce the weight to footing for greater distance. If the footing is just under the floor, then it is required to find how big it is to see if it can take the load. I don't know if it is just 10% that would be a problem but the one we fixed was 100% screwed.


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## markleena (Jan 11, 2012)

I agree with Bridgeman


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## Jdmrenovations (Jan 11, 2012)

How about a pic or two of said attic?  Could tell alot


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