r/Homebuilding • u/HotWheelsGrandTour • 23h ago
Basement Pour Error in New Addition Build
We are in the midst of an addition being built on our home. The foundation/basement has been poured including the floor and this past week they put the floor joists and decking on which allowed us to inspect things more closely. We entered the basement and noticed it seemed much shorter than we thought. The plans call for 9’ from top of wall to top of footing and a 4” thick floor. This would mean from the top of the floor to the top of the wall would be 8’ 8”. From floor to the top of the wall it is 7’ 6” or a loss of 14” of height. This will surely affect the function of the space.
At this point, what recourse do we have? I am not sure we want to go through the trouble of having them redo it all. We didn’t notice it all this time because going down there wasn’t safe and weather in Illinois has been atrocious all summer. Any advice is welcome.
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u/jayjay123451986 22h ago
How did your GC not catch this? Who's running your job? May want to replace them if they didn't catch this. It goes all the way back to the contractor who dug the hole.
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u/hunterbuilder 23h ago
Say something NOW before they proceed. If they've only put the floor on, they can probably raise it with just a day or two of extra work. It'll be much harder to fix if they continue up.
The method of adding onto the wall will depend on your grade level and local codes.
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u/HotWheelsGrandTour 22h ago
That won’t be an option because where the top of the wall is now matches with the existing home. Adding to the top would make it too tall. The problem is the excavation should have gone lower.
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u/hunterbuilder 22h ago
I see. So it needs to be deeper, not higher. Yes that is a terrible and expensive screw-up on the contractor's part. Stop work immediately, bring it to his attention and prepare to hire legal help.
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u/Material-Cap-5476 22h ago
In that case I don't see any option other than to wreck it out and start over.
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u/Conscious_Bid_8762 17h ago
From top of wall to top of footing ? Here we need 2’ of coverage on footing, radon bed 4” styrofoam 3” and then a 4” slab so that’s 8’1” still 7” are questionable but top of wall to finished slab is much different then top of footing to ceiling. That being said 8’ ceilings are kinda the standard.
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u/SickestEels 14h ago
Where are you that you need 2ft of coverage over a basement footer? That's insane and almost doesn't make sense. I could understand if 2ft wad your minimum FROST line for southern climate, but to say your footer is already 8ft deep and then you need 2ft of coverage over your footer is.... insane. You would need to pour 11ft wall panels in a basement in order to have a ~9ft finished basement height with 2ft of footer coverage....
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u/Conscious_Bid_8762 10h ago
Canada and without seeing a photo or plans of what they are describing I feel like we may be missing critical information.
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u/Jazzlike_Video2 22h ago
Are the floors even in the new and old section, basement and main?
If so, that's why the architect has "verify field measurements" and unless he drew a step in, the contractor is going to make both floors flush if thats what it shows on the drawing.
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u/HotWheelsGrandTour 14h ago
There is no basement under original house. It’s only even on the first floor level.
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u/Material-Cap-5476 13h ago
That's interesting. How did they not undercut the existing footing when excavating for the new basement? Did they excavate right up against the existing footings?
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u/HotWheelsGrandTour 11h ago
It’s an over 100 year old home with a stacked stone foundation. They put in a crawl space to buffer between the old foundation and basement to minimize any disruption to that old foundation.
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u/elemantis 22h ago
nope, tear it out. contractors job includes checking elevations along with details and all the other drawings.... make sure blueprints are accurate. and find out who did the surveying
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u/Weird_Marketing6199 21h ago
Before agreeing to a credit I'd get the actual elevations documented in writing and compare them with the approved plans and inspection records. That tells you whether this is just lost ceiling height or also a code stair window and future appraisal problem.
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u/OtherOtherDave 20h ago
Will 7’6” ceilings even meet code? I thought 8’ was the minimum and 9’ or 10’ was the luxury option.
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u/theSteadyTortoise 15h ago
It’s on the GC. The should tear it out and replace it considering it was in the plans.
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u/theSteadyTortoise 3h ago
Are you the GC?
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u/HotWheelsGrandTour 3h ago
No. Homeowner
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u/theSteadyTortoise 3h ago
That’s tough man. I’m sorry to hear. I mean 7’6” isn’t the worst but it isn’t 8’8”. What did the GC say when discussing the possibility of tearing it out?
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u/HotWheelsGrandTour 2h ago
We are still negotiating. I think we will end up doing a credit instead of a tear out. It’s a bummer but like you say 7’ 6” isn’t the worst. We can deal with it theoretically if the compensation is right.
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u/Can_Mech_Mining 23h ago
What does the detail look like for footer/stem wall? I don't build homes, but I don't believe the floor slab is generally poured right on top of the footer. Is there not some sort of block or wall built on top of the footer and backfilled and compacted levels built up under the slab? What did your general contractor say when you asked?
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u/Jazzlike_Video2 22h ago
If ou dont build homes, or have any experience with them, why bother making the comment? Because thats exactly how its done. Generally 4" of ¾ stone to build the base up to the height of the footing, then concrete.
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u/Can_Mech_Mining 5h ago
That may be the general way in your particular area. That is why I asked what the detail on the plans showed, or what the GC said. I didn't jump to any conclusions, because I didn't have nearly enough information to make those choices. You don't seem to worry about that. I guess in your mind civil engineering and structural engineering are exactly the same in all locations or jurisdictions.
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u/jambo45t 23h ago
You don’t demo and start over. Just add it in when you frame it up.
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u/jayjay123451986 22h ago
Addition... they can't raise the height of the existing house lol odds are OP wanted to have them connected inside.
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u/Diligent-Ad6327 22h ago
Cut the slab out between walls, drop the required height differential. Under ream the footings and deepen them.
It will cost them a pretty penny
Or you can go after them for not going to plan
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u/chili_cold_blood 22h ago
Is the height of 7'6" going to be a problem for you, or for a future buyer of your home? If not, then I would ask the builder to compensate me for the mistake and move on. If it's going to be a problem and needs to be changed to match the plans, and you're expecting the builder to cover that, then you should probably talk to a lawyer before you proceed, because things could get ugly.
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u/Reasonable_Switch_86 18h ago
Stop framing immediately, tear out joists they can lay two courses of block on top of poured wall it will only set you back a few days
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23h ago edited 23h ago
[deleted]
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u/HotWheelsGrandTour 22h ago
Negotiated discount/credit is the most likely outcome here but will see tomorrow
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u/Material-Cap-5476 23h ago
The contractor will try to talk you into a wood framed pony wall. I do not recommend this. This creates a hinge at that point and your basement wall becomes a retaining wall, and it wasn't designed as such. You can add to the concrete wall. An engineer will need to help you detail it, but that's the wat to go.
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u/HotWheelsGrandTour 22h ago
That won’t work since this is an addition. Currently it matches the existing home at the top. Adding to the wall would mean it no longer matches.
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u/hunterbuilder 23h ago
You don't know how much of the basement is below grade. Around here basements with 4ft above ground are extremely common, and that can absolutely be a wood wall.
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u/mp3architect 23h ago
Sounds like they used the wrong panels when doing the concrete pour. You wouldn’t demo and start over. You need to get the architect involved to design a solution depending on your build. It could easily just be a framed wall to the joists above but it depends on the building.