What is the cause of this settling?

4 years ago

I'm in a new build and we have been living here for just over a year. We're going through the 1 year warranty fix cycle. I've brought these issues up with the home builder and they are trying to blame this on landscaping to avoid responsibility. I'm in the process of having the landscape company do their analysis. I'm also planning to reach out to the ROC assuming landscaping denies responsibility (I really doubt this is landscaping's fault). We had an inspector come by just before a year of living here and he was dumbfounded, unable to provide an explanation.

We live in Phoenix, AZ and had a very wet summer which is unusual and experienced much higher humidity than normal. My theory is that the trusses have begun to warp pulling up on many sections of the ceiling. The builder is saying landscape watering has caused the foundation to curl. The foundation is post tension slab and has been laid for almost a year before landscaping was complete and watering.

There are many similar issues around the house but these are the worst of each type (grout separation, 45deg cracks at door frame, ceiling drywall pulling up).

The grout separation is the only issue noticeable on the ground. From my understanding caulk is generally preferred to grout at floor/wall edges. What is more surprising to me is that the floor seems to have dropped 1/4in relative to the baseboard. I don't understand how this is possible. The wall and flooring sit right on top of a concrete slab. If the slab was to lower I'd expect both to, not just the floor.

Anyway, I'm doing my best to get the correct individuals involved to determine the root cause and solution. In the meantime I'd really appreciate some speculation to help me understand this better and be more informed when discussing with professionals.

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Comments (5)

PRO
Patricia Colwell Consulting
4 years ago
Post tension construction in my experience in Galgary was ahuge issue that had many repercussions in condo bldgs . I am not familiar with it in your area but new homes do settle and usually it is part of the reason for the 1 yr warranty check to address these issues . I think you need to see about the slab and how it was done I am not sure who you call for that in your area but pretty sure the town office can tell you. Did you do a good check on the bulder before building to see about the workmanship in other homes. This is why you have new homeowner insurance but it is pretty useless if the builder is out of business and can't be found to rectify the issues. IMO watering the yard should not have any huge effect on the slab at this stage.
PRO
PPF.
4 years ago
last modified: 4 years ago
I'm not suggesting this is the problem, but it may be good to know about.

Search the web for phoenix subsidence.

I've been in houses there that were vacant because of foundation damage caused by subsidence.
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PRO
Joseph Corlett, LLC
4 years ago
"My theory is that the trusses have begun to warp pulling up on many sections of the ceiling."

Your theory is much more plausible than your builder's. I'd find a consultant in your area that has solved this previosly.
PRO
Patricia Colwell Consulting
4 years ago
I have never heard of the the issue PPF posted but it seems like it could be the issue so make sure you find out about that for sure.
toxcrusadr
4 years ago
It's from heavy withdrawal of groundwater from aquifers, which allows the material to compact since it is not being held open with water as much. Once again, we've seen the enemy, and it's us.

State Water Resources site with maps:

https://new.azwater.gov/hydrology/field-services/groundwater-and-land-subsidence-info

Article from AZ State Univ. with photos:

https://news.asu.edu/20210603-arizona-impact-asu-researchers-land-subsidence-local-abroad

Parts of the area are sinking as much as .5 or even 1 cm per year. Which is fine if the whole surface does it uniformly, but it doesn't. Add in some artificial fill under a house that wasn't compacted completely, plus differential settling of materials underneath, and your house starts shifting and cracking.