# Drywall in attic with knee wall



## bparise (Oct 8, 2009)

We are converting a 3rd floor to finished space and I am trying to calculate the amount drywall needed for this space. I want to do it correctly with the least amount of material loss, but I am unsure how to hang the drywall to where it's both efficient and sturdy...

The pic is a "cross section" of the room.

What way do you suggest to get the most out of material?


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## CustomBuild (Oct 20, 2009)

Ask your local supplier for drywall that is 54" wide rather than the usual 48" for the angle walls. They call it "stretch board". It is intended for use horizontally, in houses that have 9' ceilings. Just buy it in lengths that you need that will fit the lengths of the rooms. Then get standard width drywall in 12' lengths for the top and sides, and use the excess for window and door returns, and inside closets. Here is another option. Rip 1/2" plywood into 4-1/2" widths and install them on the lowest part of the walls. Then you can get by with 4x10 drywall , and just butt the bottom of the drywall to the top of the plywood rips. Then cover the seams with 5-1/2" base molding. Just make sure the drywall is going to make it up the stairwell, particularly if there is an intermediate landing. On a third floor, I find it much less labor intensive to uninstall a window, and pay a boom truck to deliver it through the window. The $150 is money WELL spent. Oh, as a side note, make sure you have installed Proper Vent on the underside of the roof deck before you insulate. Hope this helps.


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## bparise (Oct 8, 2009)

CustomBuild said:


> Ask your local supplier for drywall that is 54" wide rather than the usual 48" for the angle walls. They call it "stretch board". It is intended for use horizontally, in houses that have 9' ceilings. Just buy it in lengths that you need that will fit the lengths of the rooms. Then get standard width drywall in 12' lengths for the top and sides, and use the excess for window and door returns, and inside closets. Here is another option. Rip 1/2" plywood into 4-1/2" widths and install them on the lowest part of the walls. Then you can get by with 4x10 drywall , and just butt the bottom of the drywall to the top of the plywood rips. Then cover the seams with 5-1/2" base molding. Just make sure the drywall is going to make it up the stairwell, particularly if there is an intermediate landing. On a third floor, I find it much less labor intensive to uninstall a window, and pay a boom truck to deliver it through the window. The $150 is money WELL spent. Oh, as a side note, make sure you have installed Proper Vent on the underside of the roof deck before you insulate. Hope this helps.


Thanks for your input!
First, the knee wall is 61-1/4" high ... Drywall 48" + 4-1/2" plywood would still leave 8-3/4" inches. Perhaps you misread the measurements on the picture?

My initial thoughts were...
- Angle parts of the ceiling use 54" (Piece: 54#1)
- Ceiling 48" then rip 14" from 2nd piece. (Pieces: 48#1, 48#2)
- Walls use 48" then rip 13" from the one i ripped for the ceiling (Piece: 48#3 and rip of 48#2)
- Total: (2) 54", (3) 48" per length.

If I do go this route, for the knee wall, should the 13" piece be at the top of the wall or the bottom? I figured the top because then the full-size panel would be much easier to install, but not sure if having that seem close to the angled corner could cause some visual problems.

This leaves me with roughly 8" of waste per length (from piece 48#2). I don't think I could do better than that!

Also, should I stagger the joints? For instance, starting from a corner... the knee wall a full 8' length, the angle wall 4' and then the ceiling 8'. Kind of like a brick layering?

Onto the lengths... There is no way that I'm going to get a 12' board up to the 3rd floor. I have moved subfloor up there and it was a tight fit. Getting a boom lift is *probably* out of the question. It's a 3rd story window and they are on the sides of the house. The driveway is in the front and grass on both sides of the yard.

But, the room is only 32' in length. So with 8' lengths I have just 5 more joints to mud than if I were to use 12'. So, IMO, I don't think its that big of a deal.


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## CustomBuild (Oct 20, 2009)

oops!


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## CustomBuild (Oct 20, 2009)

You can install drywall vertically as well as horizontally. My suggestion was to go horizontally with the stretch board on the angle walls and vertically on the knee walls and with the collar ties on the ceiling. This configuration eliminates having to use a ripped piece of drywall anywhere(they are prone to break if they get bumped). 
You can cut the 10' pieces before you bring them upstairs if the whole sheet doesnt fit. That makes it alot easier to carry them also.
There is a typo on the drawing. There will be a small amount of waste on the angle walls. Hope this helps.






This also eliminates most butt joints. Butt joints are much harder to tape than tapered edges.


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## bparise (Oct 8, 2009)

CustomBuild said:


> You can install drywall vertically as well as horizontally. My suggestion was to go horizontally with the stretch board on the angle walls and vertically on the knee walls and with the collar ties on the ceiling. This configuration eliminates having to use a ripped piece of drywall anywhere(they are prone to break if they get bumped).
> You can cut the 10' pieces before you bring them upstairs if the whole sheet doesnt fit. That makes it alot easier to carry them also.
> There is a typo on the drawing. There will be a small amount of waste on the angle walls. Hope this helps.
> View attachment 14876
> This also eliminates most butt joints. Butt joints are much harder to tape than tapered edges.


Thank you so much for taking the time to help me out! This is exactly what I was looking for.


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## Allison1888 (Mar 16, 2008)

*drywall*

I agree with the boom truck. We did that on our third floor--mainly because our contractor said he wasn't climbing up 44 stairs with a few sheets of drywall at a time. Money well spent!

Also, we built storage into the knee walls and added doors (the contractor used standard doors from Home Depot and cut them in half, I believe). It has worked out great. We added a light inside one of the doors, but otherwise just use it for seasonal items so didn't want to pay for lighting everywhere in there.


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## Gary in WA (Mar 11, 2009)

It appears you are using all 1/2" board. USG recommends 5/8" drywall on ceilings IF 24" on center running perpendicular or parallel. If your rafters are 24"o.c. and you want to use 1/2" on ceilings, you may have to strip (furr) it to 16" o.c. so the drywall hangs perpendicular to the framing. Only if you will be hand or spray texturing it: Page 3, Table 1: http://www.gypsum.org/pdf/GA-216-07.pdf

Be safe, Gary


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## bparise (Oct 8, 2009)

GBR in WA said:


> It appears you are using all 1/2" board. USG recommends 5/8" drywall on ceilings IF 24" on center running perpendicular or parallel. If your rafters are 24"o.c. and you want to use 1/2" on ceilings, you may have to strip (furr) it to 16" o.c. so the drywall hangs perpendicular to the framing. Only if you will be hand or spray texturing it: Page 3, Table 1: http://www.gypsum.org/pdf/GA-216-07.pdf
> 
> Be safe, Gary


Both framing and rafters are 16" OC plus I don't plan on texturing it so 1/2" should be fine all around, right?!

I would love to get a boom truck but I don't know if my house could accommodate that. I attached an aerial photo of the house. It seems to me they would have to go on the grass to get the boom to the 3rd story.

Does anyone have experience with this? Maybe I should just contact my local supplier to see if they are able to deliver.


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## bjbatlanta (Jul 16, 2008)

Window looks kind of small from the pic, but if you let them on your driveway, they can hit it. No more board than you need, the weight shouldn't be an issue. Call the local supply, they'll come out and tell you for sure. 54" may not even be an option for the window size and much harder to deal with for a DIY'er (in my opinion). You can use regular 1/2" unless there's some specific code in your area why you can't. Hang the center (top) of the ceiling first. Work down with a 48" on the angled part of the ceiling with your "rip" at the bottom. Start the knee wall with the rip at the top and a 48" up under. Offset all butt joints including the rips. A 4' butt joint is hard enough to deal with, you don't want a 5'+ joint to deal with. Cut your wall rip 1/2" short and "jack" the 48" up to it with a "roll lifter" to compensate for floor unevenness. All of your joints are at the most comfortable level. Never put a rip at the bottom unless you enjoy finishing on your knees.......


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