mrsccincy

Hi there! I was hoping someone could help me with a problem we are having with a wall in our new home (less than 3 years old). (I would go back to the builder, but they went belly-up...so I digress.)

So here's the situation...the wall is an exterior wall. It extends the height of our 2-story entry/staircase. It is not load bearing. We started noticing that it was "bowing" in the middle of the staircase last winter. At it's widest point you could see a 3/4 inch gap along the baseboard. The baseboard and drywall bowed away from the stringer. (I hope I'm making sense here...I posted photos below). We called out a structural engineer to see if it was built incorrectly and he confirmed that it was indeed built correctly. Once spring came around the wall moved back into place. We decided not to caulk or trim it because we wanted to see what happened when it got cold again. Low and behold, it got cold this week and it is starting to move again. Argh...I'm so frustrated!

We don't know what to do. The structural engineer assured us that it is safe, but it looks hideous. Any ideas how to fix this? Would insulation help? Can we trim it in a manner that allows for fluctuations? Thoughts?

(Also, if you think I should be posting to a different board please let me know.)

Thank you!!!!

Wuzzat?

How did these experts account for your house's symptoms? If they "don't know", what are reasonable steps to find out?
My guess is that this non-load-bearing surface is bearing some load.

The amount the wall is compressed in a vertical direction such as to cause a 3/4" deflection in 16'
can be calculated if the shape of the wall is known.
This curve could be a catenary but the engineering toolbox section on load bearing vertical beams may have the equation for this type of curve.

If you think of the wall as a column with an unusual cross section, then, maybe. . .
http://www.cs.wright.edu/~jslater/SDTCOutreachWebsite/column_buckle.htm

Or, while the wall is curved, stretch a vertical line and measure the deflection from the vertical at several different points.
Then the compressive distance can be figured graphically. We could be looking for 1/8" or less, vertically, but we need to know the shape of this surface.
If something is pushing out the wall horizontally at the 8' height the curve of the wall will be different than if the wall is being compressed vertically.

Good problem.
I'm wondering if it more depends on the humidity of the inside or outside air, rather than the temperature.
Does the ground freeze in winter at your location?
Do the other walls do it?

nealtw

Is this the baseboard at the landing at the bottom or at the expansion joint level with the upper floor? If this is a raised landing, how high is it from the base of the outside wall? And welcome to the site.

mrsccincy

Yep...they "don't know." They cut a huge hole in our drywall to see if the wall was built correctly and they said it was. But, they suspected temperature fluctuations...so that's why we waited it out. The engineer said the only way to fix it was tear it down and rebuild it with steel.

mrsccincy

nealtw - Just saw your reply. It's not at the landing. I just remembered I took photos last year. I've attached them. I hope this helps. Sorry, I'm no expert here. :-/

mrsccincy

Wuzzat - We are in Cincinnati so we do get a little bit of ground freeze. And, no, this is the only wall that does it...thank goodness.

Wuzzat?

How do you know it's not the staircase stringer that's bowing? Stretch a line to check. At this point don't assume anything.

If this is the only visible symptom you may be able to fix this by modifying the staircase trim to allow a gap without it being visible from the staircase. The stringer top surface at the center would slide under the horizontal trim piece.

The question is then, "Will the eye be drawn to this uneven width spread over the staircase length"?

nealtw

When the framers built the house they crowned all the studs to the outside. They do that so that the wall dosn't have waves in it. The crown is changing with changing moisture content. The engineer probably didn't see that it went back by it self but he should have suggested tieing to the staircase. The stair case is extremely strong sideways and is nailed to the studs for support and the nails have pulled out or they were left out. I would open under stairs and lag bolt the stair stringer to the studs. It may not be able to pull them into place so maybe living thru the season and doing it when the wall comes back in place. After the studs are back in place and tight to string a 2x10 can be added on flat to the bottom of the stringer for more strength.

mrsccincy

wuzzat - The stairwell itself is straight, square, etc. Good idea on the trimming...might help it not look as obvious.

nealtw - I actually asked about tying it back to the staircase and the engineer said he was worried about it pulling on the stringer. Going in from underneath and tying it in makes a lot of sense to me too, but he made me worry that it would ruin our stairwell. Any thoughts?

nealtw

I hate to say it, because I allways tell people to talk to engineers but your guy is on drugs. Wood bends and twists all the time. When houses are built walls bend all over the place and are pulled straight and held in place with braces until the next floor or rafters are nailed in place which then holds them straight.