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I'm going to start with a question from David by email. He writes, since I last purchased your
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Cozy Cabin course, that's one of a handful of online courses I make and sell and teach
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to get me started on building my own cabin. Progress has been slow but steady. I had the
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property cleared, a well drilled, graded the building area higher due to spring water issues
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and installed a manual well pump. Hope to start the foundation soon. Strongly considering screw
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piles. With that being said, I have another question for you. From talking to neighbours
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I found out that keeping warm during the winter months is a major concern, especially on a pier
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type foundation. So that would be a building raised above the ground with an open space
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underneath, not enclosed or heated in any way. I have talked to some professionals about this too
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and the solution seems to be that I need to have a continuous thermal barrier on top of the subfloor
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and I would strongly agree with that. And then David goes on to give me a link here with the
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kind of insulation he's thinking of. And then followed by another layer of subfloor on top of
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the insulation and then the finished floor. What are your thoughts? Well, what David is planning
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to do is actually what I teach in the course, and I like it a lot. I've never seen anyone else do
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this before, but I can assure you that it works very well. If you've got a raised floor and you
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want to have warm feet in the wintertime, the tendency is to stuff some fiber based bats under
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there and hope for the best. That's not going to do much good. First of all, it's not going to make
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much of a difference because there's all kinds of air movement through that insulation, so it's
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going to be highly ineffective. Having fiber bats underneath the floor is also going to attract
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mice. They love that stuff. They'll burrow in and make nests and make a terrible mess. I have seen
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in time these bats fall out too, because every time you walk on the floor there's a little bit
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of vibration and it shakes the bat down, and unless you have something physical to hold it in place
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it's just going to fall out. So I don't like that at all, but what I much prefer is to put extruded
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polystyrene foam sheets on top of the existing subfloor, and then another layer of plywood on
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top. I like 5-8 inch plywood for that, with screws driven right down through the top subfloor
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through the foam, through the underlying subfloor, and then about an inch and a half or so, at least
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an inch and a half, into the underlying joists. So this creates a continuous barrier. Mice, squirrels
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whatever, can't get into it because it's inside your house. It's not exposed underneath, and it
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just works really, really well. Now, two inches would be a minimum, I should say. That's not
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enough to meet code requirements for floor insulation where I live, but you can add more
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to get up to the specs you need. Now, the thing to understand is, if you want warm feet in wintertime
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then you're going to need more than just a well-insulated floor. In my experience, you can
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have as well an insulated floor as you want, but if it's cold underneath that floor, the floor will
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never be warm. Now, the floor will be a lot warmer with the foam in place, but it still wouldn't be
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what you call warm. So if you want a warm floor, then an excellent option is to put some kind of
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electric in-floor heating on top of everything, right underneath your finished floor. There are
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some great systems out there. DITRA-HEAT, made by a company called Schluter, works really well. It's
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easy to install, it's effective, it's efficient, and most of all, it's reliable. I have installed
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and seen installed other electric in-floor heating systems, and it's not uncommon for other brands
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to fail in time, and that's a real hassle because you have to pick up the whole finished floor to
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find out what the problem is, and then replace it and put your finished floor back. The Schluter
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system, never heard of anyone having any trouble with it, and it just works wonderfully well. Now
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as I read David's email, I was concerned as I started to work down it for the first time
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because many times, even with professionals, they'll say, oh well, you want a warm floor
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you got to put some kind of skirting around that opening so you're enclosing it, and I really
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disagree with that. Now, David's not going to do that, but if you're tempted to do that for yourself
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let me tell you why you shouldn't. First of all, not going to make much of a difference. You can
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put skirting around there, you can put insulation around the skirting to try and boost the R-value
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but the fact is, there's no heat source down there in your crawl space, so you can put all the
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insulation on you like, and it's only going to make marginal difference. So, first of all, it doesn't
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work. It doesn't actually deliver the goods, but more importantly than that, whenever you enclose
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a crawl space, especially one where there's just natural soil underneath, which is what David's
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facing, then you run the very real risk of allowing humidity at certain times of the year to come up
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really high, because the skirting doesn't allow ventilation, and that can lead to amazingly fast
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rotting of the floor frame. I have seen two cabins, for instance, identical side-by-side, one with an
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enclosed skirt around it, one without. When I looked in the enclosed skirt one, opened the door
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there wasn't even any floor frame there. It had all rotted away and people just discarded it away
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whereas the other one was as good as the day it was built. So, do not put on skirting. There's a
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third reason too, and that's animals love to get in there when it's enclosed, and they're gonna set
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up shop and give you all kinds of problems. So, David's on the right track, and so is anyone who
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wants to warm up a floor. David's situation, he's building a cabin, he's following my design and my
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course, that's one thing. But there are lots of homes across North America where you have a bedroom
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in a space above an unheated garage. I get emails from people all the time, what can I do to warm
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the floor? Well, it's the same process. Put some extruded polystyrene foam on top of whatever
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floor you've got, another layer of subfloor, and then your new finished floor. That will give you
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insulation, and then you add the in-floor heating, and you've got a great combination. It works very
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very well. And since you're only warming the floor, you're not actually heating the space with that
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in-floor electric business, then it's quite economical. If you just use it just enough to
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keep your feet warmish, you're probably not even going to notice it on your electricity bill
