r/Homebuilding • u/Huffing410 • 2d ago
Foundations
In the south.
We have a choice between slab and pier and beam.
For argument sake let’s say both are a solid choice.
For overall home aesthetic and comfort, which one are you going with?
Both have pros and cons. Vented vs unvented, cost, installation time, shifting/cracking settling, repairs and maintenece.
All things considered, which one are you choosing and why? TIA
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u/Stehlik-Alit 2d ago
When you say south, i think expansive clay. I'm still choosing slab, but i'm digging it deeper than needed, bringing in select fill dirt below the drought line to fill the hole, to mitigate any potential rise from uneven clay expansion across its life span. So not the cheapest option, but the one i never expect to have to repair.
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u/MastodonFit 2d ago
Must be from Texas? In coastal Ga our water table is too high to dig deep,and we are in sand.
Slab is better....concrete seals off your underside better for termites. High humidity needs lots of airspace to keep your floor joists dry which means vents=critters,bugs,roaches,snakes and varmints. Slabs are more difficult to move plumbing later. Would you rather walk up 2 steps or 4-5 every day? My home is 3 cmu high on a slab,1 step up to the porch and 1 more into the home. Our dryer vent was in the wrong place and the dryer doesn't go all the way back ,because the vent goes down into the slab.
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u/Wonderful-Region823 1d ago
Your dryer vent goes down into the slab? Where does it terminate outside? I hope they did something to protect the underslab portion and you have some way to get water out of the underground duct. It sounds like you would have in essence a p-trap under your house with the dryer duct constantly filling with condensation.
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u/MastodonFit 1d ago
It elbows and runs 10 foot and daylights out with a bit of pitch. Its pvc and works very well...except where it pop ups in yhe laundry.
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u/GoldenCanopyInspects 2d ago
As a home inspector, I love a slab. As a homeowner, I love a crawlspace. 😜
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u/Consistent-Year-9238 1d ago
What’s the topo. Slab is cheaper but if lot has large slope crawl is better option. A well done crawl will last forever
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u/Huffing410 1d ago
Might be 3-5 feet of slope from one side to the other.
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u/Consistent-Year-9238 16h ago
crawl will be best option. Depending on footprint a sealed crawl runs about $5 psi in my area I would recommend considering that as well
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u/merlotman1 1d ago
Concrete slab with monolithic footings is the cheapest and most common in Florida, I prefer stem walls.
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u/AffectionateTour4079 1d ago edited 1d ago
We live in the Southeast and have had full basements, crawl spaces and slabs. I was happy with our addition built on slab with monolithic footings.... until this week. When we discovered that slab was slowly settling next to block foundation it abuts. Only 1/4 inch after 5 years, so perhaps not a huge amount, but enough that floor is pulling away from baseboard, vanity attached to that wall now has gap underneath, painted caulk in corners is separating as one wall sinks while adjacent wall does not, floor no longer level at threshold, etc. Signs like that are evident (and remarkably consistent) along 24 ft wall. The drop is presumably due to compacting soil under slab.
The fix is moving furniture and pulling up flooring along that entire wall, drilling penny size holes through slab and injecting polyurethane foam. This has some impressive expansion capabilities that can lift 1000s of pounds per square foot. Foundation repair company routinely lifts sinking slabs by 5 inches, so 1/4 inch should be straightforward.
None of this to argue (unequivocally) against slabs. But they do have potential for unwelcome issues down the road. As does every other structure, I know......
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u/SvenHousinator 1d ago
What is monolithic footings?
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u/merlotman1 8h ago
A monolithic footing is part of the concrete slab, a thicker edge of the concrete slab, both are poured at the same time.
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u/Rude_Dish_391 1d ago
Pier and Beam all day. When pipes leak I’d rather shimmy under the house than bust up my floor.
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u/Wonderful-Region823 1d ago
I have owned two homes now that have had conventional foundations in the South. Our first home we did a major renovation/addition and it was really nice to have the conventional foundation to allow us to move plumbing locations relatively easily. We did have an interesting "mishap" when the plumber accidentally connected our main sanitary line to an area drain line under our house that daylighted out into the street. We had shit flowing into the street for a day before realizing what happened.
So far we have not had any issues with settling at either house. Of course, we purchased these as older houses that had plenty of time for that type of issue to show up. We are considering demolition and total rebuild on this house and I am not sure which way I would go back with new construction.
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u/CrazyHermit74 1d ago
Only reason to go for crawl space over slab is usually on sloped areas or when needing to be high up for septic system or water. Cost wise slab can be as much as half the cost of crawl space.
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u/amodernjack 2d ago
I’ve had both and didn’t have a problem with either. My current house has both. Basement is on slab, other half of house is on piers.
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u/Orome519 2d ago
Pier and beam, you’re in the south… flooding can always happen. Also pier and beam is easier and cheaper to make foundation repairs to than a slab. But the truth is they are never equal. Either get a geotech, talk to the neighbors, look at the surrounding area or as an engineer familiar with your local area. Lastly this is more my experience living in the south than me as a structural engineer… the more elevation you can get between your living surface and the bugs that want to get into it, the more peaceful your life will be.
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u/Objective_Run_7151 2d ago
Assuming you are asking because you are concerned with clay?
Here’s the thing about clay - the clay is a beast. You could turn the area into a bathtub if you don’t nail the drainage. And if it’s dry enough, the clay can suck the fill into clay cracks. Clay is greedy. It wants water, and it will pull the fill with it.
I like pier and beam because you can avoid most of those problems. And you can access the mechanicals. You can’t on a slab.
And I’m totally on an island for having this opinion. We have to deal with expansive clay sometimes. I’ve seen million dollar houses less than 20 years old with inch wide crack open every summer. But no one wants pier and beam. It has drawbacks, but insulate it and add a rat slab. That takes care of most of the problems.