trying to estimate the combined thickness of tiles and adhesive once on wall and set.

Are we talking 2 or 3 mm, or more for the adhesive? Guess it depends on trowel used.

Thanks
Alex

You've answered your own question, the trowel notch size, level of wall etc will determine the thickness of addy once the tiles are fixed, if you use an 8mm for arguments sake, the addy will probably end up at about 3 - 4mm thick.

thanks.

reason I ask is because I'm trying to work out first fit of plumbing in my bathroom, and need to determine where the pipes should rise from under the floor. So was going to add the depth of the tiles and adhesive to the fixtures measurements to work this out.

Is this how to do it i.e. to estimate adhesive thickness?

What pipework are you talking about ? radiator, bath, basin ? Within a couple of mm you will have play I would have thought.

for WC and basin you will have loads of play, offer the sanitary ware in place and draw around the pedestal and WC pan, bring the pipes up behind pedestal and for the WC just try to hide behind the pan and use a flexi for the connection, for a radiator you will have 3-4mm play and a towel rail will normally have adjustable wall brackets so over compensate by 10mm then just adjust at the brackets when fitting

excellent, thanks gents.

Coming across the same issue with my shower.

The recessed shower valve has been fitted to the back wall. Need to now box out around the pipework and valve. The final tiled surface of the boxing out needs to be 75mm from the back wall to line up with the on/off and temperature dials of the valve. Side on view below:

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75mm
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I'll use 12.5mm hardiebacker to box in. The tiles are 9mm.

But what should I estimate for the adhesive and also the water proof membrane? The membrane has one layer of adhesive behind it, then another on top to fix the tiles. See http://www.homelux.co.uk/downloads/W...structions.pdf

I'll be using a 6mm trowel. Should I estimate 3mm for each layer of adhesive and maybe 1mm for the membrane?

How do you guys work this out?

What make of shower valve are you using?
Most types allow for some variation of the finished wall surface by adjustment of the shrouds/coverplates that slide over the controls.
Usually a rough estimate of finished wall thickness is all you need.

Thanks, there is some play, about 10mm, but just wanted to make sure I get in the right ballpark.