Tiling Issue - anyone tiled on skimmed plaster

bigpappa

In a small ensuite / bathroom I have had foam based tile backer board fitted where the wet area will be for the bath.

The other 2 walls are moisture board - but for some reason the plasterer skimmed over one wall.

Now from what I have read the max weight skimmed plaster can support is 20kg m/2 whilst plain plasterboard can support 32 kg m/2. Now my porcelain tiles are 600 x 300 and 9.5mm thick and weigh 4kg or 22.2 kg m/2 and grout and adhesive weighs about 4 kg m/2. So that is 25% over the recommended max.

This is a stud wall where the only fixture will be towel rad.

So what are my options? Crack on as I am overthinking this or just buy different tiles for that wall and make it a feature wall?

I bought my tiles last year and never got round to doing the job - though its been less than a year and I got them from Wickes.

Rosa_Damascena

Why don't you ask your plasterer? You might then learn why that given wall wasn't plasterboarded and tell the rest of us.

fenwick458

if it was me I'd want both bits of plasterboard skimmed. if you ever have to take the tiles off, or even if you decide to change the tiles in 20 years, you'll see why.

NSG666

Personally, in my home I'd risk installing the tiles you've bought making sure I used tiler's primer / SBR on the plaster. Whenever I've stripped tiles from bathrooms I've never had them pull the skim from the plasterboard. I have had the adhesive come away from the skim quite easily but that was where tubbed adhesive was used never with powder adhesive. You'll be using the latter as they are both porcelain and large format.

If the plasterer has left a highly polished finish you might want to score it with a stanley knife.

You've bought the tiles from a DIY shed who don't care about batch numbers (not blaming you). Do make sure that you check them as different batches can be a slightly different shade but also slightly different dimensions.

bigpappa

NSG666 said:

Personally, in my home I'd risk installing the tiles you've bought making sure I used tiler's primer / SBR on the plaster. Whenever I've stripped tiles from bathrooms I've never had them pull the skim from the plasterboard. I have had the adhesive come away from the skim quite easily but that was where tubbed adhesive was used never with powder adhesive. You'll be using the latter as they are both porcelain and large format.

If the plasterer has left a highly polished finish you might want to score it with a stanley knife.

You've bought the tiles from a DIY shed who don't care about batch numbers (not blaming you). Do make sure that you check them as different batches can be a slightly different shade but also slightly different dimensions.

https://www.tiles2go.net/weight-limits-wall-tiling/

Gypsum plaster walls are good quality. Walls with this well-adhered and dry plaster can support a maximum weight of 20kg/m². As a result, this wall could support ceramic tiles that are around 8mm in thickness, or stone tiles that are 7 mm in thickness.

Tiling direct onto plasterboard, without plaster skim is more stable. As a result, these walls can support a maximum weight of 32kg/m². This is suitable for ceramic tiles with a thickness of 12mm, or stone tiles with a thickness of 10mm.

I think this seems OTT.

I suppose it has more to do with standards for commercial operators who work off manufactuters recommendations who will always want as much leeway as possible?

NSG666

fenwick458 said:

if it was me I'd want both bits of plasterboard skimmed. if you ever have to take the tiles off, or even if you decide to change the tiles in 20 years, you'll see why.

As an installer on a future refurb I'd be expecting / quoting to strip the boards off the wall whether a stud wall or dot-dab then fit new boards. The powder adhesives bond to the skim far better than tubbed so it would probably pull chunks out anyway when you stripped the tiles. Only going on my experience, yours might be different.