Tile weight limits on walls

[Raccus]

ok so i read a post from Paul C on weight limits, that went:

Wall Substrate Maximum Weight of tiling per m2
Gypsum Plaster 20Kg/m2
Gypsum Plasterboard Direct (without a plaster skim) 32Kg/m2
Plywood (WBP) Up to 30Kg/m2
Lightweight Tilebacking Boards Up to 40Kg/m2. Dependant on the type and thickness of the board.
Glass reinforced Cement Sheets Up to 50Kg/m2. Dependant on the type and thickness of the board.
Gypsum Fibre Boards Approximately 35-40Kg/m2

So, quesiton is..... I have fixed marmox backer boards to plaster skimmed walls. Marmox say their boards can hold 100kg/m2 if mechanically fixed, or 60kg/m2 if fixed using adhesive. So if you have large marmox boards (120x60cm) adhesived to plaster skimmed walls, what is the weight limit? Do the boards increase the weight limit? I cant see the whole board peeling or falling off the wall beyond the 20kg/m2 weight limit of plaster.

Is there any guidance on this, or is it down to logic, eg plaster holds 20kg/ms and thats it, no matter what you put on it. And are not a majority of tiles over 20kg/m2 anyway?

 

[Andy Allen]

I would always machanially fix marmox boards using the proper washers even if using adhesive.......belt and braces as they say.
Most 600x300 and above porcelain and natural stone are pushing the weight limits on to plaster, but most ceramics should be ok.

 

[hmtiling]

ok so i read a post from Paul C on weight limits, that went:

Wall Substrate Maximum Weight of tiling per m2
Gypsum Plaster 20Kg/m2
Gypsum Plasterboard Direct (without a plaster skim) 32Kg/m2
Plywood (WBP) Up to 30Kg/m2
Lightweight Tilebacking Boards Up to 40Kg/m2. Dependant on the type and thickness of the board.
Glass reinforced Cement Sheets Up to 50Kg/m2. Dependant on the type and thickness of the board.
Gypsum Fibre Boards Approximately 35-40Kg/m2

So, quesiton is..... I have fixed marmox backer boards to plaster skimmed walls. Marmox say their boards can hold 100kg/m2 if mechanically fixed, or 60kg/m2 if fixed using adhesive. So if you have large marmox boards (120x60cm) adhesived to plaster skimmed walls, what is the weight limit? Do the boards increase the weight limit? I cant see the whole board peeling or falling off the wall beyond the 20kg/m2 weight limit of plaster.

Is there any guidance on this, or is it down to logic, eg plaster holds 20kg/ms and thats it, no matter what you put on it. And are not a majority of tiles over 20kg/m2 anyway?

Without the mechanical fixing you've reduced the hanging weight by the weight of the board and adhesive. Fix the boards with washers and scrim the joints

 

[Tile Shop]

As andy says. Weight of marmox is 3.6kgs per sqm. Plus the adhesive to stick it around 3kg. The skim still has to support the weight of everything fixed on top. Without mechanical fixings into the stud or block behind, you have a tile weight limit of only around 10 kgs plus more adhesive/grout. But put the correct fixings in, and you can use the marmox to its full potential.

 

[Raccus]

Ministry quote Paul , nice

I fixed one with the washers, but really didnt like it, they stick out too far to get a nice surface to tile over, so i ended up adhesiving the others. Ceramics going on. But concerned about weight now /

 

[hmtiling]

As andy says. Weight of marmox is 3.6kgs per sqm. Plus the adhesive to stick it around 3kg. The skim still has to support the weight of everything fixed on top. Without mechanical fixings into the stud or block behind, you have a tile weight limit of only around 10 kgs plus more adhesive/grout. But put the correct fixings in, and you can use the marmox to its full potential.

It's Harry btw

 

[Flintstone]

The washers stick out too far if there not tapped in correctly. If you used ‘spankers’ where you hammer a pin in then you need to tap the fixing in so it’s flush with the board before putting the pin in, if using plug and screw with metal washer then just screw it in tight so it’s flush. I haven’t heard of overboarding plaster solely relying on adhesive to stick a marmox board, no reason not to add fixings is there? Unless there’s complicated wires and pipes etc in the wall perhaps.

 

[Raccus]

I added some fixings today in the areas that i hadnt yet tiled, and as Local tiler suggested, i hammered them in a bit more forcefully so they stuck out less. Better. Should have just gone with that first up, its takes an age to adhesive the board on. Those spanker fixing are super fast!!! But part of the reason i adhesived was because i had a long shower tray (1.7m) and the two adjacent walls ran out, so tried to thicken adhesive as i went, to reduce this. Anyway, done now! Hope its ok!

Thank you all for the helful replies.

 

[Tile Shop]

It's Harry btw

Indeed it is. But started typing before you posted. Although you could change it to andy, one, because it makes me look less of an idiot, and two, i don't think the world can have enough andy's