durorock membrane instead of backerboard for tile

[bob]

preparing to install flooring tile in the bathroom; need to remove old tile. never done it before so i'm new at the game

folks who know better tell me that once old tile is gone i'll need backerboard for floor before tile

when i was lowe's today, i saw a new product called 'durorock floor membrane'. talking with the flooring guy at lowes (yes, i KNOW that's always a mistake), he said this is designed to replace backerboard

it's a thin epoxy that's placed on the floor. a membrane is then embedded in the epoxy and this is left to cure. when done, it protects against cracks caused by up to 1/8" movement in subfloor. it's stiff and is also waterproof, so good for bathrooms. membrane can be cut with a razor instead of a sawblade like that needed for backerboard

anyone have experience with this? any recommendations yea or nay?

thanks much

[bob haller]

He is WRONG, start fresh for the best job, if cold floors are a issue they have a electric grid that goes on between the concrete board and tile

the membrame is good and will minize cracks but first start over.

you wouldnt want to build a new home on the cracked broken footer from the previous home in that location?

[chaniarts]

you haven't defined what is under the the existing tile. what you need to do to prep the floor is different and dependant upon your situation.

for example, if you have a slab floor and it's been there for years, and there are no existing cracks, then you don't need either a membrane or backerboard. if it's a new slab, i'd use the membrane. you don't need backerboard on any slab.

[bob]

this is on an interior bathroom with a wooden floor

[bob haller]

take EVERYTHING OFF to the sub floor, make certain its secure and in good shape, replace any rotted wood check carefully , use concrete board, seal seams, then use that membrame, then tile

[bob]

makes sense to me...thanks much

[chaniarts]

agreed.

but you'd also want to make sure the subfloor doesn't have any low spots or that it's thick enough not to deflect.

[RicodJour]

There are two primary means of tile failure besides impact - flexing and tensile force. Crack isolation membranes can handle tensile force (like when bridging a crack in a concrete floor), but will not necessarily be able to handle flexing, like when a subfloor is not stiff enough and it deflects between floor joists.

Ask this question over at the John Bridge tile forums. They're primarily tile pros and have more tile experience than the rank and file in a home repair forum. I have not used the Durock membrane, but I imagine that it is their answer to Schlutter's stuff. Schlutter basically being the gold standard.

R

[HerHusband]

Bob,

First, strip the old flooring, backerboard, etc. down to the subfloor.

Next, determine if your floor structure is stiff enough to support tile. If I think there is a calculator over at the John Bridge tiling web site that you can enter your joist size, spans, etc. and it tells you if the structure is adequate for tile. If the floor flexes too much, you will end up with cracks in the grout lines, and potentially cracked tiles.

Assuming the floor structure can support tile, I used 1/4" hardibacker board. You basically embed it in thinset mortar as you do tile, then screw it to the subfloor every 6" or so. Then embed mesh tape on the seams before starting to lay your tile. Be sure to stagger your backer board so you don't end up with the corners of four sheets meeting in the same place.

In my case, the 1/4" backerboard, 1/4" thick tile, and thinset layers added up to just about 3/4" total thickness. This matched up perfectly with our

3/4" hardwood flooring for a perfect transition.

Anthony

[bob]

perfect! thanks anthony....looks like that's the way to do the job