I’m face nailing my new hardwood flooring (Tasmanian Blackwood 19mm x 130mm) then puttying the knot holes and nail holes. This will be done through the whole house. The subfloor is Particle Board (Brand name: Yellow Tongue) that has been glued and screwed down.

My question:

In the bathrooms I want to do a boat deck look. To accomplish this I’m going to waterproof the subfloor (there is also a floor drain in the event of flooding) then use strips of Dupont Flexwrap under the hardwood, between it and the waterproofing in the nail areas only so when nailing it will seal the nail holes. Finally I will use black Sycaflex or a comparable product to seal the spacing lines (I will be leaving equal spacing between each board) after I have applied a water resistant finish. SO, is the Dupont Flexwrap needed to seal the nail holes or is this just overkill?

  • Wherever water infiltration is concerned, there is no such thing as overkill.
    – Tester101
    Nov 1, 2012 at 11:16
  • Why are you face nailing? Hardwood is usually nailed through the tongue. Nov 1, 2012 at 12:56

1 Answer 1


Without the ability to dry on both sides, your hardwood flooring will eventually warp and crack unless you completely seal the surface.

You can use woods like Ipe and Teak in wet situations (and indeed, those are the woods traditionally used for ship decks) but I don't think Tasmanian Blackwood has the same resistance. There's at least one amazing bathroom designer here in Houston that built an Ipe shower floor...

Cabot & Rowe Ipe Shower

... but that's got the drain below a 'tray' made out of ipe that can be removed so that it can be cleaned, refinished and/or repaired easily. It's strips of Ipe with gaps between them that are then nailed to cross-pieces that sit in the sloped pan of the shower. I'm not totally clear from your posting, but from what I think you're looking for something like that for your entire bathroom?

The only other alternative that I can think of for you is face-nailing the wood, and then sealing it completely with an epoxy polyurethane. However, this floor will be extremely slippery when wet.

But, in general, wood floors in bathrooms are a bad idea and are something that you should rethink.

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