Waterproofing under screed? - Tile Advice

[Ozzy]

Ok, I'm a bit confused. I've been talking to my customer about her bathrooms as she is having mostly wet rooms. She has said the waterproofing is being done under the screed. Is this normal practice abroad?

 

[Dumbo]

When you say screed are you talking screed or a levelling product .

 

[Italy]

Ok, I'm a bit confused. I've been talking to my customer about her bathrooms as she is having mostly wet rooms. She has said the waterproofing is being done under the screed. Is this normal practice abroad?

in Italy, is as in uk

 

[Italy]

sometimes, it is waterproofed before the screed, but it's just an extra precaution. then proceed as usual. waterproofed before the tiles.

 

[Ajax123]

from a purely technical point of view a screed should always be divorced from the substrate by means of an operational DPM. This is usually a simple 1200 gague polythene membrane and sometimes a more complex drainage membrane or liquid DPM. if there is insulation also under the screed i.e. floating construction then a second "slip" membrane, typically a thinner 500gague membrane should be placed over the insulation before any underfloor heating pipes or screed. so waterproofing under the screed is perfectly normal. However this will NOT protect from the effects of water from above so in the case of wetrooms and showers and of course if possible bathrooms then a separate tanking system is ideally used prior to tiling.

 

[Ozzy]

That's great, I now have all the info I need to insist on tanking the wet rooms myself, I'm rubbish at explaining things so thanks. I always tank shower areas and wouldn't have been happy leaving this out. Probably off to Qatar on the 10th March, I can't wait to get started, she has some amazing Tiles! Looking forward to some sunshine too

 

[Ozzy]

When you say screed are you talking screed or a levelling product .

She said screed. It's so hard to get things clear talking to her through email. I just want everything right before I go over.

 

[Dan]

Call her.

 

[Ozzy]

Spoke to her last night, I'm supervising the screeding when I get there and she's agreed for me to do the tanking.

 

[Dumbo]

Spoke to her last night, I'm supervising the screeding when I get there and she's agreed for me to do the tanking.

What about screed drying times . Isn't that going to hold you up .

 

[White Room]

To be honest I feel your getting a lot put on you, do you have any experience with screeds.

 

[Drainage by Design]

Probably off to Qatar on the 10th March

The pactice there is normally to use bitumen-based LAW (sometimes torch on, like rooing felt) and the screed is then laid to cover it up neatly before tiling. Sometime insulation is used under the screed. UFH not normal
Under-tile waterprofing is not always accepted as necessary.

 

[Kevbos]

In Sweden they use plaster board on the wet room floors then tank room all into one drain. All pipework is surface mounted mostly .so only weak point in wet room is the 1 drain. Yes plaster board. It breaks and flexes with there floors. It was a shock but it worked

 

[Drainage by Design]

Plasterboard - it breaks and flexes with their floors.

But is the substrate concrete slab or timber ?

 

[Kevbos]

There usual building is made mostly out of wood etc .