Water Proof between Cement board and Kerdi Niche

[thomps8383]

I have a Kerdi Niche with the remaining walls in the shower surround cement board. What would be the proper way to seal and water proof the seam between the cement board and Kerdi Niche?

I planned on putting TEC Hydraflex waterproofing on the cement board, can this also go on the Kerdi Niche?

Thanks for any help in advance

[CaliGrown]

After you tape and thinset the seams in the Durock, do the same at the kerdi board to cement board junctions. Once cured and dry run the Tec Waterproofing business as usual

[thomps8383]

Can the waterproofing go on the Kerdi Niche also? Or just waterproof the seam between the cement board and niche and leave the remaining portion of the niche without the waterproofing?

[Tiger Mountain Tile Inc]

You can overlap the seam with the waterproofing. Once you thinset the mesh tape on just cover the thinset with the waterproofing liquid.

[thomps8383]

Thanks for the help.

[thomps8383]

So after the thin set dries water proof everything but the inside of the niche?

[CaliGrown]

Yes sir, that’s the ticket

[smifwal]

is that drywall mud or white thinset? I ask because you have grey around the niche and white every where else

[thomps8383]

Shawn, No everything on the cement board and niche is thinset. White is just what they had for a modified thinset that's on the cement board. The gray thinset is a unmodified according to Kerdi spec's.

I'm going to use the unmodified thinset for the niche to set the tile to comply with kerdi instructions and modified on everything else to set the tiles.

[ss3964spd]

Troy, since your combination of materials and installations strays from Schulters recommendations for their products, thus precluding any possible warranty claim you might bring, you honestly have nothing to gain from using an unmodified thinset mortar.

The modified you have used on everything else will be absolutely fine for the niche.