Backing board compression

[Anna Rack]

Got some 6mm backing boards on which I hope to lay some 30mm or maybe smaller mosaic tiles.

The board feels fairly compressible (by hand at least) and was wondering if sinkage with very small tiles might be an issue.

I phoned the manufacturer (Prowarm) and they seemed to think it would be fine although weren't 100%.

Anybody had an issues?

Thanks in advance.

 

[Diamond Pool Finishers]

Be very careful if the board is to be on the floor, it should be screeded/self-leveling-compound should be laid over it to a depth as to offer some protection against point loading of the board.......

 

[Anna Rack]

Thanks. According the manufacturer the boards have a 30 t/m2 compression strength.

If my maths is correct this means a 30mm square tile would take 27kg. Does this sound adequate?

If I went to 50mm tiles that would increase to 75kg which sounds more than adequate bearing in mind (excuse the pun) I wouldn't be wearing high heels in the toilet?!

Found this description for a board which has the same specification:

PCS Wetfloors and Tile Backer Boards are made from extruded foam (agglomerated styrene particles). As a result the density weight loading is 30 tons per sq metre.

This may sound a lot, but gives us the confidence to permit use of tiny (25mm x 25mm) mosaic tiling. The maximum point load per tile is therefore 18.7kg per 25mm x 25mm tile and customers can have total peace of mind that the tile will not sink into the board.

 

[White Room]

50mm is the minimum with foam boards, as DPF said you will have point loading...

 

[Musivarius]

I did wonder, a while ago I contacted I think Wedi or Kerdi about setting a mosaic on one and they said it a minimum of 100 mm for them to still guarantee.

 

[Ceramico tiling]

Yeah i dont feel comfortable using foam/fibreglass boards for floors unless !