Hello Everyone,. I'm in need of how-to to build a knee wall around my attic. When the house was built in the 30's, they used only 2x4's for rafters and some of those are actually failing. And, needless to say, there is a definite bow in all sides of my roof. I was told a knee wall would be the best fix.

Thanks for any help anyone may have. :)

If you put in a knee wall you'd need support from below,where it would then support the roofline.

I am not sure how to re-support the rafters,especially after they are warped.

Maybe another will have an idea for you.

Ken

Ken, thank you for your response. Not sure, though, what you mean about needing support from below... of course there are the cross supports spanning the attic floor, is that what you mean? Not sure of all the "technical" terms, lol.

Support from below would be what we call a load bearing wall.

The floor joists are only supported at the walls, if you put a knee wall in, there has to be a load bearing wall beneath to allow the new weight it is supposed to be carrying.

Think of a clear span, 12 feet across,these are your floor joists.

Now putting a knee wall in the middle.

Where does the weight settle? Right in the weakest point, where the most 'deflection' will occur.

Without a load bearing wall below to make the ceiling stout enough, a snow load... etc, would make the ceiling bow just as much as the roof is.

Hope this clears it up a bit,

Ken

It does clear it up for me. Thank you very much! You explained it very well. Is there any way to shore up the existing rafters? Maybe short support pieces from rafter to floor?

That I am not going to be able to describe,since I can't see your project.

Try a local carpenter/general contractor, they can look closely at your requirements and advise you as to alternatives.

Ken

Putting in those "short pieces" is the same as putting in a knee wall and the has the same problems. The best fix here would be to sister in some 2x6's beside the 2x4's.