Soil report & general notes 1

[DoubleStud]

So typically most counties I work with require soil report as part of their submittal package for a permit for residential construction. I often have to get my design/drawing done before I get the soil report. This is typically happen on small addition projects. I had a project where we did a garage expansion. I have done a project in the same subdivision and the soil report I got for that other project was 2000 psf bearing pressure with spread footing. On my general notes I say that I am using an assumed value because soil report was not available. Soil engineer needs to verify my assumptions.

For this project the building department never requested the soil report. I went to the jobsite to inspect the reinforcement for the foundation. Where the foundation ties to the existing house I noticed the existing house was on drilled piers. My design for the garage is spread footing. I talked to the owner and told him what was going on. He decided to just move forward and pour the foundation.

What do you think I should have done? I feel like the general notes on my drawing will protect me if in the future the garage moves up and down (because they did not verify my assumptions with a soil engineer). I also feel that the damage will not be dangerous to human if it does occur. So we went ahead and moved forward according to plan. Was that the right move?

 

[sponton]

Well legally speaking, you did have a note on it. Ethically speaking, once you've found out about faults in your design assumptions and if you feel that someone's life is being endangered, you're supposed to report it.

 

[phamENG]

I'd follow up with a letter and require a response from the owner. State the situation, reiterate the terms/conditions of your agreement as they apply to the situation, your opinion/recommendation as stated on site, the owner's decision, and the fact that they owner will hold you harmless and indemnify you from any and all future serviceability problems that come from this.

I agree, this isn't going to be destabilizing or endanger anyone. But somebody will be pissed if (when?) all the drywall in the vicinity of the connection starts cracking and nails start popping.

 

[EZBuilding]

For this project the building department never requested the soil report. I went to the jobsite to inspect the reinforcement for the foundation. Where the foundation ties to the existing house I noticed the existing house was on drilled piers. My design for the garage is spread footing. I talked to the owner and told him what was going on. He decided to just move forward and pour the foundation.

What do you think I should have done? I feel like the general notes on my drawing will protect me if in the future the garage moves up and down (because they did not verify my assumptions with a soil engineer). I also feel that the damage will not be dangerous to human if it does occur. So we went ahead and moved forward according to plan. Was that the right move?

Did the owner make a decision by themselves or were you a party to that decision? Were you hired directly by the owner or a third party? Did you advise them of this issue?

I would recommend having something in writing to the owner/your client advising them of what happened, how it does not meet the requirements of your structural drawings and advise them on some of the possible consequences.

You may be "legally covered" based on your note, but you would still likely spend several times your fee defending that your actions met the standard of care.

 

[Greenalleycat]

Using some recent lessons shared in our country, 100% you must document this in writing to protect yourself
State that the design has changed without consultation, your assumption was not verified as legally required on your drawings, that you recommend the project is halted until verification and any necessary fixes are completed, and that you will not issue any form of signoff or have further involvement in the project unless this is done.

If they don't get on board, contact the local authority and provide them with your letter

 

[Smoulder]

Why is house on piers a soil report problem? Do they dig up the footing when doing the report?

If going the down in writing route, i guess you need to say your design isn't adequate. How does that sit?

 

[Greenalleycat]

Bearing pressures tend to be a lot higher under piles than under spread footings so potentially this invalidates the design
This whole thing seems stupid though, you either decide it's ok and have the information to prove it, or you don't
As the engineer involved you have to be one the one to make those decisions or else walk away from the project and thoroughly document your concerns to the client and the authority
You can't have it both ways - be concerned and lacking information whilst continuing to be involved and reinforce poor behaviours from the client

 

[kipfoot]

To the letter that you are already drafting according to phamENG's post, I'd add a sentence or two about the possible consequence of proceeding:

"Foundations placed on unsuitable subgrade can result in differential settlement. This will manifest as masonry cracks, sloping floors, out of plumb walls, and the wailing cries of lamentation from women, children, and men (but not me, because I told you so)"

This is much cheaper to fix now than it will be to fix later.

 

[jerseyshore]

As soon as I saw the piers I would insist (demand) a soils report before proceeding further. We as engineers make assumptions all the time, but when we get evidence or proof that our assumptions need a further analysis or revisions, that's when we have to act.

A little general note is nice, but that is not going to stop a costly lawsuit when this thing starts sinking.

I'm not sure if I would even do this, but if you absolutely wanted to take that risk and build this thing on spread footings, you have to have the owner sign off on a very nicely worded document that you are not to be held liable if something happens in the future.

 

[dauwerda]

A little general note is nice, but that is not going to stop a costly lawsuit when this thing starts sinking.

OP is in Colorado, I think it is fairly safe to assume that the piers are there to mitigate movement due to swelling soils (CO is full of expansive clays). I don't think "sinking" is a risk for the spread footings, but differential movement between the two structures is almost guaranteed to happen with the two footing types.