# Slab vs. block foundation



## ELM (Jan 10, 2005)

I am not in the trades but I need some advice for building in Southern Ohio. I see a lot of homes going up on slabs here. What are the issues. Do you have to have a footer below the slab for outside walls, I see some buildings going up without.
I am looking at building some duplexes on some of my property. Simple, one story, ranch. I grew up building houses with my dad and we always had a foundation and crawl space.

Thanks!


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## Bob Kovacs (May 4, 2005)

Even with a slab on grade, you need footings at the perimeter to below the frostline (which I don't know the depth of in Ohio, but I'd guess it's in the neighborhood of 2 1/2 to 3'). There are what's called "Frost-proof Shallow Foundations", which rely on layers of insulation to isolate the building from frost heave, but they haven't caught on much yet. That may be what you saw when you said there were slabs with no footings.

Not to be harsh, but I'd seriously think hard before diving in to "building some duplexes" if you're having to ask basic questions like this, though. On top of all the other complexities of homebuilding, attached housing adds a host of fire-rating issues to the construction process.

Bob


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## ELM (Jan 10, 2005)

Bob I see your point, now what is the big advantage of slab other than speed and maybe some plumbing issues?

Thanks again.


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## TimNJ (Sep 7, 2005)

Slab=cheaper and slab=colder (unless radiant is installed, but then it is not cheaper)


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## JustaFramer (Jan 21, 2005)

Fire rating shmire rating. The best fire rated wall(s) I ever seen were some party walls with 1/2 osb, 2 layers of a 5/8 gypcrete fire rated wallboard, 1/2 sheet rock. On both sides of the party wall. 

Me's no expert but me's thinks that is a 2 hour fire wall maybe a little longer.


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## 747 (Jan 21, 2005)

www.superiorwalls.com 5000psi and ready for drywall. Foundation put in under one day.


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## Glasshousebltr (Feb 9, 2004)

Elm, in southern Ohio your frontlines probably at 24" like ours, but I'd check with the local building dept. and go a little deeper.

That's good advice from Bob. Multiple dwellings will run into a lot more than single family, all the way around. If you really are serious about it, factor in a contractor or find a good honest fella with the knowledge to back you up. This is not an area gun-ho will pay.

Bob


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