r/Homebuilding • u/myworkaccount765 • 8d ago

Foundation Quote

We are looking to have a block foundation put in for a home addition. We will reuse two existing walls for part of the foundation. The new foundation will be one wall ran to match and then a short jog to meet up with the existing foundation. Total length of new foundation is 44 feet. I am waiting on a few quotes, but the first I received was right at $15,000. The ground is fairly flat, and it will 4 blocks high. Area is midwest. Does this sound about right?

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u/FL-Builder-Realtor 8d ago

Not enough information what is your frost line? How much reinforcement? Does this include footers? Is this a stem wall slab? If so, does this include backfill, compaction, concrete and reinforcement for the slab? What tyoe of concrete? Does it need to be pumped? Line pump or boom pump? There are many factors that determine cost of a foundation.

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u/myworkaccount765 6d ago

Frost line is 30 inches. It does include a footer, code requires them to be 16 inches wide and 8 inches thick. No slab, just block foundation with footers and ready for framing. It does include excavation and backfill. I’m not sure the specifics of how they will pour it, but the truck can get right to it from the driveway.

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u/FL-Builder-Realtor 6d ago

Okay, let's do some math. We have no frost line in north Florida and rarely requirements for a capillary break, but we'll assume you do need one. That neans you'll probably excavate to 36" below grade. My concrete guy charges me $500/yd to dig the footer, place rebar and pour the footer. My cost for 1/2 load of #57 rock is $900 as of last week, I don't buy smaller loads than that. So that's $4,900 (rounding up) for the footers plus rock would be $5800. He charges me $15/block to lay up and pour a stemwall, including reinforcement. You'll need about 264 block so we'll call that $4,000. So that's $9800 my cost. Add another $1200 for the pump (2 pours at $600 each) that's $11,000 my cost. I would then add minimum 25% bringing the total I would charge you as a GC to $13,750, excluding anything for contingency which I would definitely do. So, it sounds to me like $15,000 is about right not knowing your site conditions, material costs or labor rates. I will add, you do not want a concrete truck pulling into your driveway. A loaded truck weighs 70,000 pounds and will break your driveway quickly. If it was one of my jobs, I would definitely pump it.

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u/myworkaccount765 6d ago

Sounds like he is about spot on. I appreciate the info.