slanted living room floor

I placed a bid on a garden style condominium that is 2 floors. My unit would be on the second floor. The living room floor is a little slanted. There is of course a unit below me. Does anyone know what could possibly have happened. The condo was built in 1984. Is there something I should do? thankyou for any info.

Reply to
rogv24
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Either it was built incorrectly or it has settled. Hard to say without seeing it.

Retract your bid and run. Since this may be a structural problem and its a condo, its unlikely that you could or should make any repairs.

Reply to
hawgeye

Reply to
PaulS

Modern kiln-dried dimensional lumber should not shrink to any noticeable degree. Now if you are talking rough-cut green lumber, then, yes, shrinkage tangential to the grain is significant as, to a lesser degree, is radial shrinkage.

Matt

Reply to
Matt Whiting

My comments were based on pg 102-103 of Journal of Light Construction. "Kiln-dried lumber is stamped K-D (kiln-dried) or S-Dry (surface dry), and is shipped with a moisture content of about 19%... In a completed building, framing eventually dries to an average of 6% to 11% moisture content.." An example is given of two 2x12 girders supporting a second floor. It states: "The two 2x12 girders in this building will shrink enough to cause a 1/2-in. drop in the second-floor level- enough to cause nail pops and cracks in the finishes."

Maybe shrinkage is negligible in your region, so it is not an issue for you? Probably the first response - poor work or settling- is what happened. Paul

Reply to
PaulS

I don't know where they got their numbers, but 1/2" of change over

11.25" of a 2x12 seems extremely high. For example, let's take pretty much a worst case scenario using the figures above. I'm using as my reference the "Wood Handbook : wood as an engineering material" as published by the Forest Products Laboratory of the USDA Forest Service in 1999. This is considered by many to be the "bible" with respect to wood.

On pages 277 - 279 are the formula for wood shrinkage and a table with shrinkage coefficients for most commonly used wood species. Douglas-fir is commonly used for structural members and has one of the highest shrinkage coefficients so I'll use that as nearly a worst case specie. Its coefficients in the radial and tangential directions are 0.00165 and

0.00263, respectively. Let us again take the worst case and assume the 2x12 was cut from the outer part of a very large log and thus has the grain oriented such that the tangential direction is along the 12" dimension of the 2x12. Now, let us take the worst case and assume the moisture content changes from 19% to the bottom of the range above.

The equation for relative shrinkage on page 277 is:

Delta_D = D1 * [Ct * (Mf - Mi)]

Substituting the above numbers yields:

Delta_D = 11.25" * [0.00263 * (6 - 19)]

Delta_D = -0.38" ~ -3/8"

3/8" is a fair bit less than the 1/2" stated and this is pretty much a worst case situation which is fairly unlikely to occur. I'd say something on the order of 1/4" or less would be much more typical. If you can see a slant in the floor due to a 1/4" (or even 3/8") drop across a span of 12-15' or so for a typical living room, then you have better eyes than me! :-)

Matt

Reply to
Matt Whiting

Don't forget, Matt, that if the whole building is made of wood, you shouldn't get localized floor sloping because of shrinkage. The whole thing shrinks similarly. The difference comes when you mix bearing types, and go several storeys. IIRC, a flat 2-by plate can shrink up to 1/8". Count them up in the wall section, and multiply by that number. Joists shrink by about the same amount. Add those on too. The difference grows as you go up. (Good argument for waiting before bricking.)

If a floor is sloping there is either a problem like settling or deflection, or he's on a higher floor that is bearing on something non-shrinking on one side only (which is legal, but sort of a problem if you like level floors.)

I remember a buddy fighting with a developer who wanted to mix bearing in his project. (Sorry Pat). The client was selling the units from plans, so he could care less. My buddy lost that one. The building ended up having the predicted humps in the floors over the steel. When this happened in the middle of a room, it was quite noticeable.

This gets me thinking... if the shrinkage was predictable, couldn't we have engineered the steel so that it would be close to level when the shrinking stopped? Sorta like the camber in a pre-stressed T flattening out after it's loaded....Ping, Bob Morrison!

Reply to
Michael Bulatovich

I though that it was little high as well. I'd recommend talking to the downstairs tenet and see if he's also having problems. If so I would suspect the foundation may have sunk too much on one side. Perhaps the exterior walls are settling but not the interior piers. Do the doors and windows work OK? (That's a telltale sign of uneven settlement.) If the foundation's OK, I would suspect a beam that's sagging.

Reply to
Dennis

There has always been a problem in mixing steel and wood in a single building. Care must be paid to the detailing to allow the wood to shrink (howbeit ever so small). For floor joists supported by steel beams, one possible method is to raise the top of the joists above the top of the steel beams using a shorter than normal joist hanger.

Steel columns present more of a problem than joists. This is especially true if the columns are built into a wall. Not to much if the columns are out in the middle of a room. Again, careful attention to details can reduce the problems.

Reply to
Bob Morrison

Especially if the steel is exposed to wide temperature variations since steel expands about 3X more than wood with temperature changes. Wood moves with humidity and steel moves with temperature.

Matt

Reply to
Matt Whiting

I was thinking more about compensating for the cumulative shrinking you get in multi-storey wood buildings where one end of a set of joists might bear on a line of bearing is non-shrinking. Presumably it could be anticipated to some degree of accuracy...As you go up the difference can be 3/4" (not negligible.)

Reply to
Michael Bulatovich

Quite true. A proper design will anticipate the shrinkage in the wood and attempt to compensate for it. I find it generally is not a good idea to mix wood and steel unless the steel can be isolated out in the middle of a space. Example: steel columns in a partial underground parking space supporting wood floors above. The wood may be supported on a perimeter wood framed wall with beams spanning over the parking spaces and steel pipe columns. There will be uneven shrinkage, but the slopes will be so small as to be unnoticeable.

Reply to
Bob Morrison

So in a mixed structural system you would ordinarily compensate for wood shrinkage by shortening your columns a bit?

Reply to
Michael Bulatovich

Not my usual choice since the framers will will add shims or other devices to make the beams level.

I usually just try to avoid mixing steel and wood in the same wall. Any required columns in a wall are made up of built-up studs or use one piece posts if that works better. Even better is to avoid using steel at any level that has wood walls, I.e. use it only at the basement level.

I realize that with steel moment resisting frames this is a bit more of problem. In the case of a multi-story building I try to interrupt my frames with a bit of wood floor framing. This at least limits the problem to a single floor.

If you like I could send you a detail (off list) of how this works.

Reply to
Bob Morrison

That's my general approach too, but sometimes you've got no choice...

Reply to
Michael Bulatovich

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