foundation for cold weather

[flyfisherx]

Re: foundation for cold weather

John, you have done very well. Things are looking great. I think we tend to worry too much and over analyze everything we do. BTW Mike at Southbury Stone and Supply hooked me up. I made the mistake in bringing my wife....now I'm doing 8'x 9' cultured stone veneer on my living room fireplace. This will hopefully help my mortar skills when I get to my dome.

I too was worrying about frost, but as Mingy said, you don't see foundations on sidewalks. I think at best they dig down 8 or 10 inches, put down a gravel base and pour concrete.

I am going the sidewalk approach. I live on serious ledge. I can't put a shovel anywhere in my yard without hitting rock

Original poster JGV109: I live in New England and see no issue with a floating slab as long as your not attaching it to any other fixed structure.

[Mingy]

Re: foundation for cold weather

Aegis,

That looks great. I am lovin' your roof lines.

I will have to ask my building inspector about the footing for my oven. He said, "footings below frost line." I will ask to see if there is an alternative.

Mingy,

I read an article a while ago that said something along the lines of if you make a pier foundation the piers should not be "attached" to the slab. It, meaning the slab, should almost ride on the piers. The gentleman in the article placed something between his piers and the slab. Like a felt or tar paper. Does that sound correct?

David

Most cities don't look at code for buildings below a certain size, usually about 100 square feet. Also, code is primarily associated with the safety of habitable buildings, which is obviously not the case with respect to overns. In the case of an oven, you want to pay attention to fire codes are another matter. I would ask any inspector to show me where code calls for a 36 square foot structure which is non-habitable (basically along the lines of a dog house) has any code requirements whatsoever. You don't want to make war with an inspector, but he's not the guy excavating and pouring and extra yard of concrete for nothing.

I'd ask a structural engineer if I had any doubts, but I don't have any doubts because I have one 24x40 foot building sitting on a slab on grade for 12 years and will have a 40x100 foot one built this summer. The existing building and the planned building slabs were both designed by structural engineers. This is required by code more to make sure the total load (building, contents, snow) will be adequately supported by the slab, especially around the periphery which bears the majority of the weight of the structure. Long story short, in a slab on grade building, the peripheral concrete is about 12" thick (I don't have the plans with me) and has a fair bit of rebar in it. This is just because of the weight of the building, contents (the new structure is 4000 square ft and has a second floor) and snow, not because of frost heave. Of course, if I had a soft soil like sand or something it might be different.

In any event, Usually they put tarpaper (or kinda like a cardboard tarpaper) so one concrete thing doesn't bond to another. Nonetheless, if your slab is sitting on the ground and it is on piers below the frost line, frost heave will cause the ground to force up on the concrete. If, for example, you have rebar between the piers and the slab, this will produce tremendous forces on the slab and piers. Perhaps the piers will be lifted, perhaps the slab will crack, maybe you'll be lucky and nothing will happen. If the slab is not fixed in any way to the piers, than it'll go up and down with no stress, which is exactly the same thing as if there were no piers there.

[Dino69]

Re: foundation for cold weather

Thanks, Mingy.

I will have to go down there and have a non-confrontational meeting with him. He actually seemed like a nice guy. Admitted he had no idea what I was doing. Maybe he just threw out the "footing below frost line" thing because he didn't know what else to say.

Thanks again.

David

[Mingy]

Re: foundation for cold weather

Its good your inspector is nice, most of them are but they have to put up with a lot of BS and irate people sometimes. I try to use a sort of collaborative approach. You might be able to find the local codes on line and now where you stand. Do some research on 'slab on grade' construction and bring it with you.