tilted floor in hillside house

[structural3]

I am checking a house which is sitting on a sloped lot. Assuming you are facing the house, the front left side is two car garage and right side is downstair entry leading you to a living room. All the rest of the rooms are located upstair, one the back side of garage there is a door which leads you into crawl space underneath the partial 2nd floor, the grade sloped up to higher level where there is a 2' tall masonry stem wall supporting the upper floor joists. At back side of garage wall line, there are regular 9' tall wood stud walls in the crawl space you can see which is supporting the upper floor joists.

The house was built in 1971, the floor are tilted towards to the front side of building. I am not sure if this shall be a concern, it is not quite noticeable when people work in but it may be observed by some expert. the floor is not level but how bad will this cause normal people's concern? Let's say the elevation drop 2" over 25' distance on 2nd floor, is it too much or can it be more? Building code doesn't define the limit and there is no crack found in foundation or interior walls, there are hairline cracks everything on exterior stucco wall, that's about it. All doors and windows are easily opened without any problem.

What's the maximum acceptable slope on floor level in a residential house? is 1/8" to 1 feet slope a concern or 1/4" to 1 feet drop a concern?

I found that one side of floor joists sit on masonry stem wall (with rock base) and the other side of floor joists sit on wood stud wall (9'-0" tall at crawl space) with regular concrete stem wall on surface soil (I guess), I think this is the reason causing the differential settlement. it seems the foundation has evenly settled on a bearing line, therefore this is no crack found anywhere in the house except stucco hairline crack.

Please let me know what you think I need to do to make me comfortable with this issue. I can send some layout if it helps you understand what I asked.

Thanks

Janet

 

[BAretired]

A 3" drop in 13' from Gridline 2 down to Gridline 3 seems a little excessive but part of it may be due to shrinkage of the wood. I am attaching your sketches with gridlines shown for ease in discussing.

If the Living Room floor consists of wood joists platform framed as opposed to balloon framed, you could have substantial shrinkage relative to the masonry wall which has none. Your section does not indicate the First Floor structure, but I am guessing it is stick framed over a crawl space.

If the material was very wet during construction, each plate could shrink by 1/8" and the joists another 3/4". Assuming 3 plates below and 3 plates above the First Floor, this could account for 1.5" differential movement.

That still does not account for 3", but the remainder of the floors seem to have moved a similar amount when the shrinkage is discounted. Perhaps the contractor had a wonky level.

If were purchasing the home, I would want the Second Floor leveled or at least one constant slope. A buyer should be advised of the discrepancy in levels so that he may consider the potential for additional movement.

BA

 

[structural3]

Thanks for your valuable comments. Please explain why there are "3 plates below and 3 plates above the 1st floor". The total number of plate on stud wall line 3 below 2nd floor level is only 4, therefore the no. difference is only 4-1=3, with 3x3/8+3/4, I only get 1.125" please explain where you get 1.5", also my field measurement of top of stem wall elevation along line 3 from grid 3 to 4)gives 1" difference. Therefore I got 2.125" total difference here. Just .875" short from 3".

What do you think the best way to fix this kind of leveling problem? please note that I have not noticed any drywall crack at all inside the house, I assume drywall shall respond to this 2" shrinkage change with cracks.

Unfortunately, the floor elevation drops 2" from grid line 3 to grid line 4 on 2nd floor between line A and B too. How do we explain this, both floor joists were supported by sticked framing. (Yes the crawl space is supported by sticked frame per your assumption)

Janet

 

[structural3]

Assume the leveling problem is caused by wood shrinkage, I don't think it will be a cheap fix too. If we put 2-2x flat on lower side of 2nd floor level and install plywood above, the problem shall be solved. what do you think of this solution?

Janet

 

[BAretired]

Normally, there is a single bottom plate and a double top plate in every story. If your situation is different, then please advise. My assumption was that the stub wall below the First Floor would have a single bottom plate and a double top plate below First Floor.

Above the First Floor, I assumed a single bottom plate and a double top plate at the underside of Second Floor. I cannot confirm this in your case, but it is standard practice in my neighbourhood.

Leveling the Second Floor by adding another plate under the Second Floor joists seems like a reasonable solution to me, but if the problem is foundation settlement, it will not help if the foundation continues to settle differentially.

As for the 2" drop between Grids A & C down to Grid B, there is not enough information to make a reasonable guess. In northern Canada where I live, I would suspect frost heaving on the outer walls, but in California where you live, that is not likely to be the case.

BA

 

[structural3]

"Leveling the Second Floor by adding another plate under the Second Floor joists..." will be expensive fix. I was proposing a cheap fix (definitely not a perfect one) by adding 2x flat on top of floor joist as long as you don' have door/opening near these area....

There is no pony wall at crawl space therefore, only three plates shall be calculated, right? (one plate on top of stem wall at crawl space, two top plates under 2nd floor joist, that's about it)

Thanks.

Janet

 

[BAretired]

Janet,

Your solution seems okay to me. A doorway should not be a problem. Simply cut off the plate at the edges of the door.

BA