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Recommendations for Temporary Basement Covering

| Posted in General Questions on

OK, our Cabin foundation is in (please see attached photo).  But we probably won’t start construction ‘til the Spring of 2022.  Meanwhile, another one of my goofy ideas; If we put a roof on this basement/crawlspace, we could have a) dry, lockable storage, b) a temporary bathroom in the basement, hooked up to septic, and c) a patio deck of sorts.  For b), our excavator is looking out for us; he’s hesitant to install the septic tank until we have something to hook up to it, so that frost doesn’t pop it out of the ground.  For c), patio deck . . . right . . .  as if we would ever sit down.    😉

Anyway, my plan is to use the I-Joists and rim joists that I spec’d for the Cabin floor.  And then add some tapered sleepers to the top.  Probably ½” per foot of slope.   And then ¾” CDX plywood on top of that.  For keeping it waterproof (including the LSL Rim Joists), I could apply a torch-down roll roofing.  But that seems like it would end up in the landfill.

-What alternative roofing products could I use?

-I thought about metal roofing, but we’ll be walking on it.  Maybe I could have my local vendor provide just flats sheets?

-Or maybe paint on a waterproof deck coating?  (In grey, to avoid excessive heat gain.)  I suppose I could reuse the coated plywood elsewhere.  And I could cover the LSL’s with coated plywood, too.  Perhaps flash the outside edges with metal corner flashing.

-Other thoughts?

Thanks in advance,


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  1. Miles007 | | #1

    Here is the photo. Not sure why it wasn't attached above.

  2. Miles007 | | #2

    The footprint is 16' x 24', and the project is located in Skamania County, Washington.

  3. brian_wiley | | #3

    You might consider a billboard tarp. They can be purchased in a number of sizes and weights, are typically waterproof (most are, but some are not; double check with the vendor), and because they're already on their 'second life' are probably more green than selecting a new product.

    Additionally, you can trim them down after the initial use (two 16'x12' tarps in your case; just a little Bron Tape and some grommets and you're set) to get even more life out of them.

    Here's a link to one such company to give you an idea, but you may have luck locally reaching out to an outdoor media company. I used to work in environmental graphics, and depending on the time of year many vendors couldn't give them away.

    1. Miles007 | | #4

      Hey, that's a great idea. Thanks Brian!

      1. Expert Member
        MALCOLM TAYLOR | | #5


        The big box stores sell pond liners remarkably cheaply. You could re-use it as an under slab vapour-barrier.

        Whatever you choose, take the time to get it waterproof. I've seen several local homeowners do the same thing during their builds and end up with framing damage and mold after a winter (or in one case several) of small leaks in our PNW weather.

        1. Miles007 | | #6

          Thanks Malcolm, that’s good advice.

    2. Miles007 | | #7

      BTW, do think that 1/2" per foot of slope is enough?

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