Crawlspace into living space?

Started by Schifference, July 26, 2017, 07:25:28 AM

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Schifference

It seems that crawlspaces have moisture issues and many people suggest encapsulation.

I have a home I purchased that needs new floor joists, beams, and piers on the first floor. The home sits on top of a concrete block perimeter vented crawlspace in South Carolina.

I have been entertaining a few thoughts.

Suppose I eliminate the entire first floor framing and pour footings and foundation where I want carrying walls. Then lay vapor barrier and pour a concrete floor and have my new concrete floor become my first floor floor. Wouldn't that turn my crawlspace into living space that is conditioned allowing to naturally have the cooler area help keep my home cooler? This would probably be more work than I would want to do but I was curious about the feasibility of the concept. Basically the first floor gets lowered about 18 inches and the crawlspace gets eliminated. I understand I would have to deal with sewer lines and water lines. Electric can easily be routed.

A simpler idea that I would like feedback on would be to dig a trench burry some type of sealed vent pipe below the grade of the crawlspace. I was thinking if I circulated air in a sealed vent pipe below the crawlspace, I could cool my home and warm the crawlspace, eliminating condensation and mold issues. I was thinking that would be like a conditioned crawlspace without the need for vapor barriers and whatever else goes into encapsulating.

What do you think? I would love to know.
Thanks

NathanS

The problem with the trench is that air is not a great conductor, it would probably take a ton of pipe to drop the temperature sufficiently - especially in South Carolina. Also without dehumidifying the air, if you are introducing some of that SC 100% humidity 100F air into a 60 or 70F pipe, you may have some serious condensation issues inside those pipes, probably wouldn't smell too good. I'm not sure about SC, but I would be thinking about radon gas if I was doing something like that around here.

In the north they actually do drill horizontal lines through the ground, maybe 5-6 feet below the surface, and pipe water through them. They use a compressor to both heat and cool buildings this way.


GaryT

IMHO, this is the route to go.  I'd just re-do the crawlspace to these specs.  I think you'll just have the same problems if you try to make the crawl into living space without this sort of remediation.
http://www.finehomebuilding.com/2015/05/13/creating-a-sealed-crawlspace

Gary

Don_P

You won't have the same problem if you go your route of pouring a slab and including that space in the conditioned envelope, that is what a sealed crawl is doing. Insulate the walls and underfloor. There is a hinge created there that isn't great but probably not horrible either. You can also fill the crawlspace with gravel, screed it level, cover with foam sheets and poly, and pour the slab on top at present floor level. Half of my ~30 year old house is on a raised slab like that, the other half is over a sealed crawl with a thin slab poured over gravel and poly.