[Lovey1103]

I had a 14'X14' four season porch built on to hour home 15 years ago.
Around year 7 I noticed some difficulty opening the door and windows, nothing concerning but noticeable. Fast forward to year 10 and the porch was tipping, walls cracking, bookcases pulling away from walls and so on.
Since we were still under the 10 year warranty the builder came out and jacked up the porch and placed wooden shims under the posts. (a very weak fix for sure). Fast forward 5 years, the porch is tilting walls cracking and so on. The builder wants nothing to do with it and told me so.:vs_mad:
I am now in the quandary to figure out what to. We are on clay soil and realize now we have a soil compaction and sinking footing issue.
I will get a structural engineer involved and am asking you what the fix is for this mess? We live in Minnesota and the footing are 6" down which is a couple of feet more than code. Will they have to be removed:surprise: and replaced? I'm sure this will be expensive. Any idea how much? This is a 2nd story porch as we have a walkout.
Thanks much in advance.

 

[Daniel Holzman]

I don't really understand your post. You say you are getting a structural engineer involved, but you want the advice of an internet chat forum? You should have a contract with your structural engineer that specifies what you want them to do. Options include:

1. Perform a visual investigation to evaluate the cause of the problem.
2. Perform tests, either soil borings or test pits, to confirm the cause.
3. Recommend alternative solutions to the problem.
4. Prepare a cost estimate to have the problem fixed.
5. Assist you in selecting a contractor to perform the work, prepare drawings and specifications as needed, and file for a permit (if necessary).
6. Observe contractor work to make sure they perform the work correctly.

You can tailor your contract with your structural engineer any way you like. Or you can hire another contractor to fix the problem. The difficulty with hiring a contractor directly is that you may end up with the same problem all over again. At least with an independent structural engineer, you get someone who has no financial interest in a particular solution.

 

[SPS-1]

Your footings are 6 inches down or six feet?

Could be they are deep enough, but not big enough in diameter, so that the weight is too much for the amount of soil they are sitting on. Are they sinking?

Consulting a structural engineer sounds like a good idea.

 

[Thunder Chicken]

If they just dropped sonotube down a 6 ft hole without any flare or footing at the bottom, they probably don't have near enough bearing area to support the load in clay. To get decent bearing area they would have had to trench out and put elephants feet on those tubes.

You might be able to install more footings to support the load, but if they're sinking they are significantly undersized and you might have to add a lot of them, which may be difficult depending on access. Getting enough bearing area down below frost line will require a lot of digging.

Definitely need an engineer to get loads and dimensions. Hopefully they can come up with some way of getting support under this that doesn't involve tearing the whole thing down and redoing it.

 

[Tom738]

I had a 14'X14' four season porch built on to hour home 15 years ago.
Around year 7 I noticed some difficulty opening the door and windows, nothing concerning but noticeable. Fast forward to year 10 and the porch was tipping, walls cracking, bookcases pulling away from walls and so on.
Since we were still under the 10 year warranty the builder came out and jacked up the porch and placed wooden shims under the posts. (a very weak fix for sure). Fast forward 5 years, the porch is tilting walls cracking and so on. The builder wants nothing to do with it and told me so.:vs_mad:
I am now in the quandary to figure out what to. We are on clay soil and realize now we have a soil compaction and sinking footing issue.
I will get a structural engineer involved and am asking you what the fix is for this mess? We live in Minnesota and the footing are 6" down which is a couple of feet more than code. Will they have to be removed:surprise: and replaced? I'm sure this will be expensive. Any idea how much? This is a 2nd story porch as we have a walkout.
Thanks much in advance.

Listen to the structural engineer. Also consult an an experienced construction lawyer in your state quickly, like this week, about whether you have any way to hold the builder accountable for his seemingly negligent or fraudulent repairs, etc...--if this goes to court there will be a fight about what statute of limitations applies, so best not to miss any deadlines.

 

[craig11152]

Was there ever a permit/inspection process?

Here in Michigan before footings are ever poured an inspector has to approve the dig..... assuming anyone actually pulled a permit.

 

[SPS-1]

All the inspector is going to do is check that footings are to required depth and to plan. He is not going to do the calculations to check the weight on each footing is suitable for the soil type.

 

[Thunder Chicken]

All the inspector is going to do is check that footings are to required depth and to plan. He is not going to do the calculations to check the weight on each footing is suitable for the soil type.

True, but they know what a pier should look like for a 1 or 2 story structure, with a proper flared bearing surface at the bottom, vs something that might only be sufficient for a deck. They can also require stamped drawings which ensures an engineer has done the calculations AND that the construction matches the calculations.

It sounds like the crew that did the footings for the OP dropped 6' sonotubes down holes with hardly any bearing surface. That might pass for a lightweight deck (maybe), but no way could it be adequate for a framed structure. I'd be curious to know what diameter the sonotubes were.

 

[craig11152]

All the inspector is going to do is check that footings are to required depth and to plan. He is not going to do the calculations to check the weight on each footing is suitable for the soil type.

Fair point but if it all passed inspections by a Government entity every step of the way then I might ask what level of culpability do you think the builder should have? What should he have been expected to do over and above what building codes and practices require? What should he have been expected to foresee beyond the "norm".

 

[SPS-1]

The diameter of a footing is unlikely to be found in any building code. It depends on too many things and thus must be calculated by a competent person.

 

[Thunder Chicken]

The diameter of a footing is unlikely to be found in any building code. It depends on too many things and thus must be calculated by a competent person.

I know that. I was asking about the diameter of the sonotube.

 

[MI-Roger]

I had a 14'X14' four season porch built on to hour home 15 years ago.
Around year 7 I noticed some difficulty opening the door and windows, nothing concerning but noticeable. Fast forward to year 10 and the porch was tipping, walls cracking, bookcases pulling away from walls and so on.
Since we were still under the 10 year warranty the builder came out and jacked up the porch and placed wooden shims under the posts. (a very weak fix for sure). Fast forward 5 years, the porch is tilting walls cracking and so on. The builder wants nothing to do with it and told me so.:vs_mad:
I am now in the quandary to figure out what to. We are on clay soil and realize now we have a soil compaction and sinking footing issue.
I will get a structural engineer involved and am asking you what the fix is for this mess? We live in Minnesota and the footing are 6" down which is a couple of feet more than code. Will they have to be removed:surprise: and replaced? I'm sure this will be expensive. Any idea how much? This is a 2nd story porch as we have a walkout.
Thanks much in advance.

The weight of the added 2nd floor 4-season porch obviously exceeded the bearing capacity of the original first floor porch footings, or the bearing capacity of the soils.

New larger diameter concrete piers or retrofit helical piers to add support to your existing piers without removing them. Here in S-E Michigan, I have received helical pier quotes of ~$1500 each. Multiply this by the number of existing pier footings. Contractor should be able to install 5 of these in under 4 hours, so your yard is not destroyed for weeks as with some other solutions.

Just adding additional piers may be a good solution too, depending on your egress needs from the house area beneath the porch.

It is possible the existing posts go all the way to the bottom of the holes augered by the original builder. This is very poor design/construction because even with the hole filled with concrete the post can separate from its concrete envelope and the full bearing pressure is concentrated on just the end of the typically 4x4 wood post.