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Community and Q&A

HardieBacker Cement Board for Closing Bottom of Porch

NICK KEENAN | Posted in General Questions on

I need to close off the bottom of a porch. Normally my go-to would be pressure-treated plywood, but it’s running about 75 bucks a sheet these days. My local big box has 4×8 sheets of 1/4″ Hardiebacker for $21.  I think it would be pretty good for this, it’s tough and impervious to the elements. Nothing is going to chew through it. My only concern is it might be a bit brittle.


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  1. Expert Member


    Don't see why not. It's just getting it in place in one piece that may be challenging.

  2. Expert Member
    BILL WICHERS | | #2

    Densglass may be a bit easier to work with here, it's not as brittle and it's easier to cut.

    If you do go with hardibacker, or any other fiber cement product, remember to take precautions when cutting it to avoid exposure to silica dust.


  3. user-5946022 | | #3

    If it is a wood frame porch, does it need ventilation underneath?

  4. user-2310254 | | #4

    I like the Densglass idea but would be concerned about the canary yellow with gaped decking. I'd probably want to paint it a dark color just to be safe (from an aesthetic standpoint only).

    1. Expert Member
      BILL WICHERS | | #5

      If you don't care about a sandpaper-like rough finish (densglass isn't as smooth as regular drywall), you can just paint it with a sprayer. The final texture will probably be something like the rough side of a sheet of hardboard, a bit like a combination of coarse sandpaper and window screen. A heavy coat of paint should hide things enough to be passable anywhere it's not a detailed finish piece.


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