Maximum tile weight on sand/cement render backing

[sajid78]

Hello - I'm a homeowner in the process of choosing tiles for a bathroom in a newly built extension. The inner leaf walls are Thermalite 3.6N blocks with a sand and cement render inside.

What's the maximum weight of tile that backing could take? I could find lots of information on the maximum weight supported by plaster, plasterboard, backing boards etc but not sand/cement render. I was also not sure if the Thermalite blocks behind the render are a limiting factor in any way.

Most of the tiles we are looking at are porcelain tiles, sizes around 600x300, around 25kg/m2.

Any advice would be much appreciated!

 

[Dave]

There is no stated weight limit on sand/cement backing. But it definitely exceeds what you require with those tiles.

 

[sajid78]

There is no stated weight limit on sand/cement backing. But it definitely exceeds what you require with those tiles.

Many thanks Dave. In the shower area, would you recommend the use of a tanking / waterproofing kit on the wall before tiling? If so, would this reduce the weight of tile the wall could support? (I'm not planning on doing it myself, but just looking to inform myself ahead of talking to the tiler)

 

[Dave]

Many thanks Dave. In the shower area, would you recommend the use of a tanking / waterproofing kit on the wall before tiling? If so, would this reduce the weight of tile the wall could support? (I'm not planning on doing it myself, but just looking to inform myself ahead of talking to the tiler)

All porous substrates will benefit from bring waterproofed. As there is no suggestion it alters weight limits from info provided a few manufacturers

 

[sajid78]

Many thanks Dave. In the shower area, would you recommend the use of a tanking / waterproofing kit on the wall before tiling? If so, would this reduce the weight of tile the wall could support? (I'm not planning on doing it myself, but just looking to inform myself ahead of talking to the tiler)

Thanks, good to know that. A few years ago I helped a friend out tiling his bathroom (DIY job) and we applied a Mapei waterproofing kit onto a fairly uneven rough wall surface where tiles had been removed and taken bits of render with them. Next day, if you got hold of it in a corner, you could peel it off like a layer of skin so we ended up taking it all off as we were worried the tiles would just pull it off. Maybe we didn't apply it right, or should just not have started peeling it off... This was why I was unsure about whether it should be used on my job but if it's normal to do so on porous substrates then will check to make sure that's the plan.

 

[Russell]

whats the weight limit for a block rendered wall that has been skimmed for porcelain tiles.
Thanks

 

[Dave]

whats the weight limit for a block rendered wall that has been skimmed for porcelain tiles.
Thanks

Skimmed with what.