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I’m laying hardibacker down in a bathroom. I’ve cut all the sheets to fit with a minimum of seams, but given the toe kick on the cabinets and the other things I have to maneuver around, I think it’ll be a terrible pain to lay
it down in the thinset without making a mess of things.
I could probably do a much better job laying the board down in the thinset if I cut each roughly in half and staggered the cuts. Am I better off with more seams and good laydown, or having fewer seams and potentially disturbing the thinset quite a bit when putting the hardibacker down?
Replies
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The additional seams should not pose a great problem. Ensure at least 1/16" spacing between sheets and tape and mud your seams. Sounds like an installation over plywood. What sort of membrane is protecting the plywood?
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I was going to put nobleseal or something similar down on top of the backerboard, as it says in the
Michael Byrne book, but now I'm seeing in the instructions that it should be put below. Wouldn't you mess up the membrane by putting a bunch
of screws through it to attach the board?
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I'm laying hardibacker down in a bathroom. I've cut all the sheets to fit with a minimum of seams, but given the toe kick on the cabinets and the other things I have to maneuver around, I think it'll be a terrible pain to lay
it down in the thinset without making a mess of things.
I could probably do a much better job laying the board down in the thinset if I cut each roughly in half and staggered the cuts. Am I better off with more seams and good laydown, or having fewer seams and potentially disturbing the thinset quite a bit when putting the hardibacker down?
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Andrew, there are several ways to ensure an absolutely watertight membrane. First, as Michael Byrne has suggested, you can comb out some asphalt gum before setting the felt. The gum helps to seal the srew holes in the membrane. Or, you could lay out a membrane of Ice & Rainshield underlayment, which is self-sealing. I would be concerned over a second-story bath floor if the possibility existed for a great deal of water penetration of the grout joints. However, on most bath floors you're trying to guard against having wet backerboard in contact with plywood subflooring. Water that passes through the joints will be absorbed by the backerboard. The backerboard will stay wet until the water evaporates. So, using felt only is generally sufficient to protect the plywood substrate against intermitent water contact.