Isoquick or other ideas for slab on grade insulation in SoCal?
m4tr1x|发布Passivhaus上
Hi Guys,
Have a question, and this is my first rodeo.
Building a new home in SoCal, and I wanted to insulate the slab on grade. Talked to most contractors and they look at me like Im crazy…
During the winter months, concrete floor gets really cold, and besides putting on socks, I have been looking at radiant heating designs and Passivhaus designs with building a ‘concrete raft’ using rigid foam boards, like those from Isoquick.
那么，有什么意见？预算紧张，不想在这里赚钱，但我将做大部分的劳动。Isoquick看起来真的很酷，但他们不在美国卖出。我喜欢他们对产品的想法和易用性。有人可以帮助我弄清楚这个困境吗？提前致谢。
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Replies
Mrtr1x, you aren't crazy for wanting warmer concrete floors. Due to concrete's high thermal conductivity and high heat capacity, it will feel cool until close to body temperature. It's still a good idea to insulate, and self-forming raft slabs make it easy. This is the system I'm most familiar with:https://www.ecocor.us/foundations. (I used to work there and wrote the copy on that page, and helped assemble one raft slab foundation, among other things.) It relies on fairly thick components--good if you're building a Passive House in a cold climate, but probably overkill for your situation. Thinner parts just don't have the ability to self-brace against the large force of freshly poured concrete.
The more traditional method isn't that hard to do--just stake out a form board around the perimeter, brace it well, line it and the ground with rigid foam (borate-treated EPS or Neopor are best), cover it with a vapor retarder and reinforcing steel, and pour.
Or do an insulated grade beam foundation; I've used that system several times with mostly good luck (the bad luck being concrete contractors who understandably don't like new systems). It's probably more convoluted than you need in SoCal, but can be a good solution in cold climates.
Typically, if you heat the floor past the temp that is comfortable with shoes on, the air will get too hot. It will help if you put radiant floor heat only in critical areas.
I considered radiant for my current home, but ultimately abandoned the idea because high-mass systems were simply too inflexible for Zone 3. I looked at low-mass as well but could not justify the expense. Instead, I focused on building a tight house with a well engineered HVAC system.
If you are doing the work your self - leave the slab uninsulated or insulate just the edges as code required and add 1/2" pex tubing in the floor. Heat the pex with swimming pool hot water solar panels. You will still need to install some other heating system to meet code.