monolitic slab

[yanmars]

I have a two story building sitting on a 26x36 monolitic slab built this way. All top soil removed, maybe 14 to 16 inches. Then compacted the soil. They about 9 inches of clean gravel added and compacted. Then moisture barrier of plastic. Then rebar and mesh and 7 inches of good grade concrete added. Then sealed with Thourglaze after cutting the concrete to avoid cracking.
Then three high split face blocks and 2x6 construction on the first floor. 2x10 on the second floor in a mansard style. Have a lean to in additon on one end and a raised two story deck on the other. The floor joist on the first floor are 2x10 and on the rafters on the second 2x8. All on 16 inch centers. On the first floor three 2x10s as a beam supporting the second floor on the length, two cross beams under that and those supported by steel posts.
It has been there 23 years and concrete and blocks are good, one hairline crack of about two feet. No heaving, spalling etc. Live in Ohio.
I would like now to turn it into a hunting/vacation cabin for the kids. Add water, electric, heat etc. Bedrooms on second floor for kids. Used occasionally.
Now need zoning permits. It appears they are concerned about frost heave. Never had any so far. Initially they say I will have to excavate the entire perimeter 32 inches deep and put foam insulation up against the same. I should have mentioned that the concrete is 7 inches everywhere except for deeper areas under where the steel supporting posts are.

I have concerns if I excavate to 32 inches the gravel will to some degree come out and leave the concrete to some degree unsupported at that point. It also will be considerable expense and difficult at the deck and somewhat at the lean to. Was wondering if horizontal foam of 6 inches thick might work and even that poses some problems if it has to be covered by 10 inches of dirt.
I would have thought once heat was added to the building there would be less chance of heaving but perhaps not and more.
I am not opposed to the thought of perimeter insulation being good but it will be a difficult procedure at best. Would prefer to use EPS (Exterior Poly Shield) vs. XPS if that is acceptable.
Just hoping there is some way to do this that will work and still meet code. It is an ag storage building now and needed no permits but does if there will be any human overnight use.
Thoughts or guidance are appreciated. Thanks

 

[Snobdds]

Foam at a depth deeper than the concrete is doing nothing. Any competent inspector should know this. I question their requirement in the first place, foam on the outside of the slab doesn't do much. Foam is for under the slab as a thermal break between the ground temperature and the slab. On a basement it makes sense, but not on a monolithic pour.

I wouldn't dig deeper than the bottom of the concrete and just put foam on concrete only. Then hope you get a competent inspector.

 

[robstaples]

I would suggest their thought was the surface foam would keep the cold from penetrating to heave the footing. The building being heated would pass warm to below and not allow frost below. Why after 23 years of not heaving, but there are code rules. I would try to get an exemption. Approach from a type of soil that apparently does not hold much water, or you would have had damage.

 

[EddieWalker]

Mostly I'm commenting to follow the thread and see what you end up doing, but I am also surprised that you need a permit to remodel an existing building. Every state is different, and I'm fortunate to live in a state that lets you do what you want with your land and buildings without dealing with permits. I realize that it's too late now, but what would have happened if you had just done the work to the building without telling anybody?

When I lived in CA, they where crazy about permits. Anything over $100 required a permit. This led to very few people getting permits, and a lot of work being done under the table. When you sold a house, you just declared that no permit was obtained for the work on the house, and it was up to the buyer to walk away or accept that. It might be different now, but building inspectors where overwhelmed with new construction work to bother with remodels and additions. If a contractor went through the permit process, he had to add all those fees to the cost of the job, along with downtime waiting for the inspection. Everyone that I knew just hired whoever was able to get the job done, and nobody had a Contractors License, or bothered with permits. The cost difference between doing it legal and how most of it gets done was double!!!

 

[yanmars]

For ag buildings almost no regs or permits needed. For people buildings many, many needed. The Amish live near me and they did a number of building, remodels etc. and got in hot water over the same. Red flagged and cease and desist orders.
I am afraid if I did anything like that I would have had to tear everything out or uncover, redig everything to show compliance. I think it could get complicated if not expensive. We shall see.

 

[EddieWalker]

Since you already spoke to the government, you dont have any choice but.to do it their way.

 

[Chewwy]

For ag buildings almost no regs or permits needed. For people buildings many, many needed. . .

Not true in a lot, if not most, places. One reason for requiring permits is to facilitate taxing its value, even if its only an ag building.

 

[/pine]

In many states the real estate laws require a residential seller to disclose any improvements and that work was none by licensed mechanics etc...some states/municipalities will give waivers for qualified homeowners to pull their own permits for some of the work but some trades like plumbing, elec, AC/heat etc...often require licensed companies...
Another factor in some places is insurance requirements...if a homeowner puts an addition on their house and does all the work them self...including plumbing, elec etc...they may or may not be able to get insurance on the improvement without affidavits from licensed tradesmen saying the work is up to code etc...

 

[crashz]

Horizontal foam will protect the soils beneath it. It helps hold the heat in and will help to protect from frost penetrating beneath the edges of the slab. I have done it and it works well.

You are also right that if you excavate along the edge of the slab, you may loose a bit of soil and gravel. Depending on the soil type this could be very minor or cause a cantilever situation in which your slab is not designed to handle.

 

[Handloader109]

asinine concept to put insulation in a perimeter location either way. If not up against a solid surface like a basement, it is both worthless and I wouldn't do in this situation. It will be what is heaved.