I installed a new tub which does not have a flange.

Before I put up Duraboard what product, if any, should be used to seal the space outside of the tub's edge (garden/jacuzzi type of bathtub edge). The tub is set on the floor and has 2X4's used for leveling under its edges (alcove type of install).

Once Duraboard is put up there will be open space past the tub's edge.

After tile is put up then only the line of caulk would be preventing water from getting inside the wall. Is caulk enough, or what other sealant should I apply to close that gap?

  • of what material is the tub?
    – mike
    Nov 4, 2013 at 4:23
  • Stack exchange loves pictures.
    – Bryce
    Nov 4, 2013 at 6:06

1 Answer 1


No, that's not sufficient.

I would epoxy a flange to the tub. And then for good measure use some roofing tape (which is flexible) to backstop the flange. And maybe for really good measure install a pan under the tub, or a the very least some building paper leading to a visible spot below (so you quickly detect any leak).

Remember that most building materials can survive getting wet periodically. No building material can survive staying wet. Trapped water means mold, rust and worse.

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