Advantec x-factor?
stephenr
| Posted in General Questions on
Hi,
I am doing a concrete free slab in coastal Maine. When I lay my subfloor, it will be over compacted sand, 4 inches of EPS, a vapor barrier and sleepers. It will be exposed to the elements for about 2 months before I can get it dried in. I dont want rain to penetrate the subfloor, get trapped by the vapor barrier and be a problem. How shall I subfloor?
Advantec?
Advantec with seams taped with zip tape?
Advantec x-factor?
Advantec x-facor with seams taped with zip tape?
Thanks,
Stephen
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Replies
Stephen, Advantech X-factor is a great product but it won't keep rain from penetrating to your vapor retarder. If you can't get the roof on quickly, I recommend using a system that allows for rain. That's what Josh Salinger did here: https://www.greenbuildingadvisor.com/article/the-concrete-free-floating-plywood-slab-assembly.
Alternatively, you can install the whole shebang and then cover it with EPDM, with seams sealed as if it were a roof. I've had that done on a few renovations and it works well, but it's somewhat expensive. I just picked up a 10'x25' roll of EPDM at Beacon Sales in Auburn for $300.
Hi Michael,
Thanks for this video and the advice. Very helpful and timely. I just poured my grade beams. I will change the design to frame the walls and roof before the subfloor assembly. It will allow for an earlier dry-in (and keep the assembly dry), which is attractive to me.
While I have you, I need some advice on my infill. My grade beams wound up being a bit higher than anticipated (4 feet tapered down to 2 feet) mostly on account of the slope of the site and the need for soil over wing insulation. As a result, I need to bring in about 90 yards of infill. Josh had native soil, 6 inches of 3/4 gravel as a gas layer and 3/8 gravel on top of that. I plan on bringing in bank run sand, which I can get for cheap, and compacting it in 5 inch lifts with a medium -duty plate compactor. I am not concerned with the drainage needs of the infill, since I have double footing drains, a French drain at the edge of my wing insulation, and a site that falls away. I am simply hoping that it compacts well. I imagine I could also do a 4-6 inch layer of 3/4 inch gravel on top of the bank run sand as a gas layer, and 3/8 on top of that as scree. What do you think?
I did a slab less slab on my personal home, in Maine, and built it before putting up walls and a roof. I used standard advanced subfloor and taped the seams with Vana tape. I also taped the seams to the vapor barrier that went up and over the ICCF foundation wall. I just used some leftover duplex nails to hold the vapor barrier edge down on the outside of the wall.
The tape worked well, not perfect and took a serious beating. I did the framing on weekends so it was pretty slow.
It got totally dumped on by rain all fall and winter and it was a pain to keep it sqeegied off. That being said it is dry now and seems totally fine. I’ve drilled a few holes and haven’t found anything too concerning.
Grading out and compacting a large area to tight tolerances for a slab less slab is tough if you don’t have access for heavy equipment. It’s also nice to be able to snap lines and frame walls on a nice flat work surface.
If I had to do it again I think id just be a little more careful with the tape job and buy a bigger sqeegie.