Tiling inside shower cubical ? Help

[Softus]

OK; let's get to grips with this tanking thing.

1. Grout is porous, but a good grouting job will withstand more than average showering use.

2. Thin tiles have less grout to act as a barrier.

3. Poor grouting has minute gaps in it.

4. You can't stop the wall getting wet with ordinary grout.

5. If you don't tank marine ply, it won't degrade when wet.

6. If you don't tank cement board, it won't degrade when wet.

7. If you don't tank plasterboard, it will degrade when wet.

Ergo, tanking isn't the road to tiling Damascus, because it won't stop water getting behind the tiles - the water has to go somewhere.

 

[fender]

Thanks Softus,

Believe me, I'm NOT trying to argue here. So can you explain to me why a plasterboard wall I tiled 16 years ago with no tanking, showed zero signs of water damage when the tiles were removed for a refurb?

The tiles were about 6 x 9, made in Italy (quite expensive at the time) and I used a very good quality powdered "waterproof" grout.

Thanks......

 

[Softus]

Thanks Softus,

Believe me, I'm NOT trying to argue here.

No problaymo; nor am I.

So can you explain to me why a plasterboard wall I tiled 16 years ago with no tanking, showed zero signs of water damage when the tiles were removed for a refurb?

Surely that's because no water had propagated through/past the grout.

I didn't say that water always reaches the wall, merely that when it does the wall will get wet, unless it's tanked, and that the water will then have to go somewhere else.

The tiles were about 6 x 9, made in Italy (quite expensive at the time) and I used a very good quality powdered "waterproof" grout.

Larger tiles tend to be thicker, thus the grout will be thicker.

For a job to be a good one, every aspect has to be looked after. I'm perpetually replacing installations where the preparation is poor, also the adhesive quality, the adhesive coverage, the grout quality, the wall robustness, and, in fact, the entire building. The cheapo end of new builds suffer a lot from most/all of these.

You can't make a shower installation too rigid, as any vibration and wall movement will stress even the best grout/grouting and lead to cracks, which is when the soft underbelly of untanked plasterboard becomes exposed to its prey.

 

[fender]

Thanks Softus,

Good reply....

As the OP is unlikely to be a seasoned tiler, then I would go along with the others here and either tank the plasterboard, or use marine ply / aquaboard.

Being of strong character though, I thought it right to say what I've found over the years, rather than just blindly agree with everyone.....

 

[Softus]

...I would go along with the others here and either tank the plasterboard, or use marine ply / aquaboard.

I'd use Hardiebacker board, mainly to be contraversial.

(Actually it's more widely available than Aquapanel.)

Being of strong character though, I thought it right to say what I've found over the years, rather than just blindly agree with everyone.....

I completely agree. What did you say?

 

[fender]

...I would go along with the others here and either tank the plasterboard, or use marine ply / aquaboard.

I'd use Hardiebacker board, mainly to be contraversial.

(Actually it's more widely available than Aquapanel.)

Being of strong character though, I thought it right to say what I've found over the years, rather than just blindly agree with everyone.....

I completely agree. What did you say?

...Dunno, what did I say? - can't remember! Maybe I need help??

I'm off for some beers and to get off my face....

Later......

 

[gcol]

OK; let's get to grips with this tanking thing.

Yes let's.

1. Grout is porous, but a good grouting job will withstand more than average showering use.

If by this you mean that a good grouting job will prevent moisture from reaching the wall then I'm afraid this is not the case.

2. Thin tiles have less grout to act as a barrier.

Agreed.

3. Poor grouting has minute gaps in it.

All grout (apart from epoxy) has minute gaps in it. Grout is porous. (Porous = Admitting the passage of gas or liquid through pores or interstices.)

4. You can't stop the wall getting wet with ordinary grout.

Moisture will eventually pass through grout, yes.

5. If you don't tank marine ply, it won't degrade when wet.

To a certain extent this is correct. However, the wood will swell slightly when wet and if subjected to moisture for a long enough period, it will eventually rot. Marine and WBP ply sheets use a higher grade of adhesive to bond the layers together - this adhesive needs to resist moisture for a certain period of time. For marine ply this is set out in BS1088. And no, I don't have a copy.

6. If you don't tank cement board, it won't degrade when wet.

Yup. However, if wetted, it will absorb moisture. This is why I prefer the tanking solution, it's a 100% waterproof barrier.

7. If you don't tank plasterboard, it will degrade when wet.

Yup, if it gets wet it'll turn to mush quicker than you can say "Oh booger!" well maybe not that quick, but pretty quick.

Ergo, tanking isn't the road to tiling Damascus, because it won't stop water getting behind the tiles - the water has to go somewhere.

Correctamundo. If you use marine ply or cement board it'll be absorbed into that. If you tank plasterboard, it'll stop at the tanking.
This aside though, whether you tile onto tanked plasterboard, tanked plaster, marine ply or cement board, all the installations have a much better chance of success than plasterboard alone - I just happen to prefer tanking plasterboard.

 

[Softus]

1. Grout is porous, but a good grouting job will withstand more than average showering use.

If by this you mean that a good grouting job will prevent moisture from reaching the wall then I'm afraid this is not the case.

No, I didn't mean that. I meant that grout is porous, and that good quality grout applied correctly is less 'porous'.

3. Poor grouting has minute gaps in it.

All grout (apart from epoxy) has minute gaps in it.

I disagree. Being porous is not the same as having gaps of the size I'm talking about. A rush job with cheap grout has yer actual gaps in it, and/or pockets of air.

(Porous = Admitting the passage of gas or liquid through pores or interstices.)

Yes - not gaps.

6. If you don't tank cement board, it won't degrade when wet.

Yup. However, if wetted, it will absorb moisture. This is why I prefer the tanking solution, it's a 100% waterproof barrier.

Yebbut the water still has to go somewhere.

Ergo, tanking isn't the road to tiling Damascus, because it won't stop water getting behind the tiles - the water has to go somewhere.

Correctamundo. If you use marine ply or cement board it'll be absorbed into that. If you tank plasterboard, it'll stop at the tanking.

...and have to go somewhere else.

This aside though, whether you tile onto tanked plasterboard, tanked plaster, marine ply or cement board, all the installations have a much better chance of success than plasterboard alone - I just happen to prefer tanking plasterboard.

I know it. But I'm shifting allegiance from WBP ply to cement board.

 

[gcol]

 

[unibuild]

would it better to use a water proof adhesive on the plaster board before tiling, Anybody?

 

[Softus]

Eh? Before tiling?

You should certainly use a waterproof adhesive when tiling, but if your aim is to tank the plasterboard then plastering on a layer adhesive won't achieve that.

 

[JohnD]

prey

[pedant] Predator [/pedant]

 

[Softus]

Oh b*ll*cks. I stared at that for literally moments without understanding what I intuitively knew to be wrong. Ar*se.

PS Thank you.