light weight substitute for cement backer board?

[Kevin Warnock]

I recall reading somewhere on here some time ago that there is a light weight substitute for cement backer board for laying tile. Does anyone know what material I am thinking of and how to get it? I like the idea of tiling the bath area, but I am trying to keep weight to a minimum to preserve my current fuel economy of an empty shell.

Thanks

[skihor]

Home Depot carries an "underlayment" material. I can't recall what it's called. It's orange, comes in a roll and takes the place of backer board. It's used in places like cracked concrete because it isolates the tile from the substrate, as well as forms it's own backer board, so to speak. It seems like a good fit for a bus application. I haven't used the product and I don't know anybody who has tried it in a bus. Go look at it, it might be just what your looking for.
major drawback.....$1.55 a square foot.

Don & Sheila

[JackConrad]

I have not used the orange stuff, but I stripped a tile floor that was installed on top of that stuff.  It was probably the most difficult tile removal I ever did.  Jack

[luvrbus]

Read the info on the orange stuff it has no strength and is made for use on concrete to stop cracks in the tile    good luck

[gumpy]

Hardiboard comes in 1/4" and 1/2" thickness. 1/4" would work fine and not add a lot of weight.

You could also use a paint on rubber membrane on top of your plywood and tile right to that. However, I would be more concerned about tiling over plywood rather than installing backer board.

In my shower, I built the walls of 3/4" birch veneer plywood. They were somewhat flexible, being attached only to the floor and ceiling. I then mortared and screwed 1/2" Hardiboard to the plywood. When the mortar dried, the walls are as stiff as steel. I've
had no issue with cracking in my tile work for 4 years and around 30K miles.

If all you are doing is the bathroom, I would recommend using the Hardiboard. 1/4" is rated at 1.9 lbs per sq. ft. Weight will not be a significant issue, compared to the tile and mortar.