Floating Basement Walls - Contractor Talk - Professional Construction and Remodeling Forum

McMasters · 08-22-2008, 02:39 PM

Has anyone ever used or heard of "floating walls" in a basement? No I am not talking about flood damage.

Really I just had a prospective client ask me if I thought that the stud walls in a basement remodel could cause damage to the home structure due to pushing up on the floor joists.

She had someone tell her that the walls should be constructed so they could float with the movement of the slab. She mentioned Home Depot as the source of the idea or at least some book she read there.

My thought is if the slab is moving that much the studded basement walls would be the last of her problems. Any professional framers ,carpenters or builders have any thoughts on this idea.

Michael

neolitic · 08-22-2008, 03:02 PM

Rising basement slabs?
Flexible walls?
If they say so at the Despot,
it must be so.

**framerman** · 08-22-2008, 03:46 PM

I think I saw this in JLC. It's code somewhere I believe. Not everywhere.

kevjob · 08-22-2008, 04:18 PM

code here in denver for basement walls is at least a 2 inch float for expansive soils

concretemasonry · 08-22-2008, 04:25 PM

If you have expansive soils that react to moisture changes you have to have basement wall the is guaranteed to "slip" and not cause any upward load on the floors above if the slab raises.

If the soil expands, you can get cracks in the concrete floors, heaving of upper floors or both.

This is a case where the codes can protect you from yourself.

neolitic · 08-22-2008, 04:48 PM

Michigan has voodoo soil too?
Thought that was in the Rockies?

neolitic · 08-22-2008, 04:57 PM

This doesn't appear to be such a
widespread problem that a Despot
clerk would have a handle on it?
http://www.surevoid.com/surevoid_web/soil_maps/mi.html
Am I missing something here?

neolitic · 08-22-2008, 07:26 PM

Come on, concretemasonry, someone?
Got a better soils map?
I don't believe expansive soils are
a big problem in Michigan.

kevjob · 08-22-2008, 07:33 PM

How about contacting local building dept? solves all the guesswork.

neolitic · 08-22-2008, 07:36 PM

I'll bet his would say, "What?"

concretemasonry · 08-22-2008, 07:39 PM

In the "flatland" of the southern half of Michigan (north of Ohio and Indiana) anything is possible.

Some of the local clay deposits in the area can do strange things.

neolitic · 08-22-2008, 07:45 PM

Wish the OP would be specific about
where he is.

cctyler · 08-25-2008, 12:17 AM

Its standard practice in my area (North of North Dakota). Code here requires at least 3/4" gap for movement.

What do you need to know specifically?

**AtlanticWBConst** · 08-25-2008, 06:04 AM

Yes, heard of them. Saw a show, where they were installing them/how they were doing it. Not alot of call up here in the Northeast for such.

Link on discussion (how to frame floating walls): http://www.betterbasementideas.com/i..._in_basements/

K2 · 08-25-2008, 07:15 AM

Floating walls are the standard along the front range of Colorado because of soil conditions. You'll also find some other types of construction practices that are probably different than other areas for example, foundations without footings to give a more concentrated load , and also voids under concrete forms, (placing cardboard boxes in the bottom of the form,), again for concentrated loads.

Floating walls have become the standard framing practice around here for slabs even when the soil condition does not reqire it.

I drew that floating wall detail in an engineers office in September of 1982 and it was on my engineering and everyone else's the next day. Before that we were floating 3/4 of an inch and just letting the concrete nails float the 3/4. I have not been able to find that detail anywhere before Sept 1982 so for now i take credit for it.

cmansmith · 08-26-2008, 10:43 PM

I live in kansas city and we float all our basement walls 3/4 inch. I don't think its code but our builder had problems in the past and requires us to do it.