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

 

[msquared48]

A cross section would help... Immensely.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[JAE]

I don't think there is a code provision that requires a certain limit on floor slope. It is usually what the owner will put up with and also whether the slope is indicative of an on-going settlement or a settlement in the past that has now stopped.

You could monitor the elevations around the perimeter of the house over time to see if the settlements are still occurring.

Underpinning the house is an option - an expensive one. You can underpin to simply stabilize or you can also try to jack up the house to level - but that can be difficult depending on the house configuration.

 

[a2mfk]

Agree with Mike, I got lost in your narrative. A picture or sketch is worth a thousand words.

Where is the location? Is that area known for unstable soils such as plastic clays, organics, etc?

I deal with this type of stuff every day. What it boils down to is if there is no distress, especially structural, and the owners are OK with the slope, there is no problem. If the slopes are barely perceptible and have led to no decrease in function of the house, then what is the issue..?

How much of the floor slope is due to original construction and how much due to settlement? Nobody knows unless you have a floor elevation survey soon after construction.

For monitoring purposes you could have a floor elevation survey done for future comparison so that you have an established baseline.

 

[TheoreticalHope]

Call you local inspection agency. Often they have deflection and levelness criteria not specified by the code.

For Ontario, Tarion sets the gov't standards for final inspections and they have rise over run limits for walls, foundations, floors etc. (I can't remember them off the top of my head).

The number of houses with floors sloped or uneven is significant, most people either just don't notice or care to repair the floor.

If the settlement, progressing over 40 years, can only be noticed by an expert. I don't think there is much of an issue.

I would suggest go buy yourself a laser level from Home Depot ($120) and get an accurate measurement of key points on the floor joists and foundations. Record the relative settlement accross the structure and tell the homeowner to call you, or to hire someone who can measure and compare your data in a year's time. Ongoing or recent settlement is a problem. Existing settlement which is barely noticeable after 40 years, not so much.

 

[Den32]

Difficult to follow without some diagrams or photos. There could be numerous reasons.....?

Also, what is your scope? Are you hired by a current owner? Prospective buyers? Did they specifically ask you to review the sloped floors or did you notice?

Are all the floors sloped the same (first and second)? Are there interior bearing walls?

 

[structural3]

I went back did more measurement accurately and had some concern and questions.

The main concern is there is a 3 inche drop from grid line 2 to line 3 (13' distance) it seems too much. I included house layout in this post.

a)all floor joists run up and down assuming north is up
b) grid line 1 to 2 is upper side of sloped lot (flat)
c)grid line 2 to 10'down toward south direction is sloped down soil, (the crawl space can be accessible from back side of garage at grid line 3)
d)At grid line 2, there is 4' tall masonry stem wall supporting the 2nd floor joists.
e) At grid line 3, there are 8' tall stud wall supporting upper floor
f) all floor sloped down towards the front at a 2" drop over 20' distance, the worst one is 3" drop over 13' distance between grid line 2 and 3.
g) I don't understand why floor sloped down in E-W direction from A and C towards the grid line B, as I don't think grid line B has load bearing wall (since floor joists run N/S direction), grid B is the lowest point line in E/W direction.
h)I measured garage stem wall top elevation, it shows only 1" drop in N/S direction over 20' distance, it seems that soil has not settled too bad due to the help from concrete slab in garage. where is the 2" difference on 2nd floor come from? Maybe from wood construction.

Based on the above information. do you concern if this house is worthwhile to buy as I could not monitor its settlement change and have to make decision to proceed. Is this required to be retrofit or will you live with it. What do you feel the best way of solving the problem.

Thanks so much for your help!

Jan

Again the house is built in 1971, no crack on footing and interior wall of the house except hairline crack everywhere on exterior stucco, the doors and windows open smoothly.

aaaaaaaaaaaaaaaaaaaa grid 1
a a
a 2nd floor a
a a
a 51' a
aaaaaaaaaaaaaaaaaaaa grid 2
a a
a 2nd floor & a 13'
a crawl space a
aaaaaaaaaaaaaaaaaaaa grid 3
a a a
a a1st floora 13'
a garage a Liv rm a
a aaaaaaaaaaa grid 4
a a
aaaaaaaaaa 30'
21'

A B C

 

[a2mfk]

Seriously? Don't you own a scanner? They are like 50 bucks...

 

[structural3]

Sorry don't know how to delete the previous post, but this layout works. Garage size is 23'x21'.

51'
aaaaaaaaaaaaaaaaaaaaaaaaaaaa grid 1
a a
a 2nd floor a 18'
a a
a a
aaaaaaaaaaaaaaaaaaaaaaaaaaaa grid 2
a a
a 2nd floor & a 13'
a crawl space a
aaaaaaaaaaaaaaaaaaaaaaaaaaaa grid 3
a a a
a a 1st floor a 13'
a garage a Liv rm a
a aaaaaaaaaaaaaaa grid 4
a a
aaaaaaaaaaaaaa 30'
21'

A B C

 

[Den32]

Jan,
This seems pretty involved. (And the scanner comment is true - hard to decipher). Not sure if you are a structural engineer, but you should consult with someone in person regarding this because it seems too involved/complicated for this site.

Not trying to be rude, but this would either take a bit of time/energy to get into, or I would just be 'throwing guesses' out there, based on my understanding of the issue(s). Either way, seems beyond this forum.

Maybe someone else thinks differently.

 

[structural3]

ok. I thought it's easy to type a layout, but since you mentioned scanner I will attach the more professional one here. I have never load pictures here, so not sure how many pictures I can load up.

Yes, I am an engineer.

 

[structural3]

See section too.

I pretty much know the retrofit method, just wondering if this condition is a concern, it may not be a big deal and it is not necessary for retrofit, All I need is field person/contractor's opinion.

 

[cvg]

since this seems to be a settlement issue, I would expect to see some information regarding the foundation conditions, soil types,cut/fill/depth to bedrock, groundwater, drainage etc. which could be used to evaluate settlement. Kind of hard to render any opinion with nothing to go on but a "schematic floorplan". The problem can't be "solved" until the cause has been identified.

If I had to guess I would say there are multiple issues with this house, not the least being the fact that everything rolls towards the front door. This is a big red flag and personally I would look for something better to buy.

 

[structural3]

The soil in this area is typically good. (correct my previous post, there is no bedrock base under, it's only soil). No foundation cracks were observed as I mentioned, there is only less than 1" drop in both directions between 20' distance on top of garage stem walls.

For this kind of problem, they usually asked you to consult a structural engineer, which I already have the knowledge, I understand 90% of time, engineer will say, the house needs to be leveled, but I hope to talk to some engineer with construction experience or experience contractor, who can give me some valuable insight,personally, I think this may not be a problem but I need some backup/knowledgeable opinion. Where can I find this kind of service?

Thanks for reading such a long post.

Janet

 

[msquared48]

I would definitely investigate settlement of the footing line at the top of the slope. Don't know which gridline that is . Classic condition for a slip or rotational failure.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[structural3]

This line is the line of masonry stem wall I mentioned which is sitting near the top of high side of sloped grade, I agree with you that you think it may slide down as section shows too close to the sloped grade, but the top of floor joist does not drop down that much at all at higher grade elevation, about 5/8" drop over 12' distance at higher grade.

This wall is on the north side of 3" drop I have measured over 13' distance. I am more concerned why this 3" drop occurs.

I don't think this stem wall slides towards to the bottom of the sloped "hill", otherwise floor elevation on this line shall be lower instead of 3" higher. (my section may not be accurate since it drew stem wall too close to the sloped edge.)

Thanks.

Janet

 

[JStephen]

A number of years back, we lived in a house where one end was about 2" lower than the other. The only effect of this was that the gutters were sloped the wrong way and wouldn't drain.

 

[csd72]

Is there any possibility that the house could be sliding down the hill as well as settling?

I would be very wary of that house.

It could be symptoms of a larger ongoing problem.

It indicates that the current owners are not high into the maintenance.

If it was a simple fix then the current owners may have done it.

 

[a2mfk]

LOCATION?

I would have a company come in and do a floor elevation survey of both stories so you have the complete picture of what is going on with the floor slopes and elevations. Maybe you see the whole house is sloping one way, or maybe this is a localized settlement issue. This should be a pretty cheap test, at least it is when we do it. Also gives you a baseline for monitoring purposes.

Then you can investigate all the things the other engineers have mentioned above.

You said not foundation cracks that you could see so far, that is a good sign, but as others have said this may be a global movement issue.

 

[structural3]

Remember this is a upsloped house, not downsloped one. The lower level stud walls are sitting on street level, therefore, it can not persuade me that the house will slide down. Because the middle potion of the house is supported by concrete stem wall close to the sloped edge, so if the house slides down, the middle line shall be lower but the floor is tilted down from that line to the front 3" over 13' distance. My guess is differential rigidity of support walls (one side concrete and one side wood....not exactly sure??)

Anyway, I guess I have to find some retrofit expert for wood construction.

Do you know that if I am a potential buyer, should I write a report of this investigation and give it to the contractor for estimating the cost of repair? We will then submit it to the seller, is there any legal issue to cause problem of my license?
Should I hire other structural engineer since this may not convince seller what I did is based on professional's opinion.

Janet