Tiling on Universal Shower Bases

[Melbourne Builder]

Hi there - I’m hoping to get some advice.

I’m a builder, based in Melbourne, Australia. I’ve recently done a few bathroom renovations, using a Universal Shower Base, where a fibreglass shower base is installed and then tiled over.

These jobs were all completed in the last few months, using the same tiler, but I’ve had call backs on two of them, where the grout has cracked/fallen out. One of these jobs, I’ve been back to twice with the tiler, who has scratched out the grout lines and re-grouted - the first time adding a plasticiser to the grout and the second time using epoxy grout. I did notice that there were ‘pockets’ in the grout lines that seemed to be like air bubbles? The cracking is still occurring and when I went round again, I noticed that a couple of the tiles were bouncing at the point where they meet the tile insert shower waste and I could hear water underneath.

It looks as if I will now need to pull the shower base tiles up (ugh!) to see what the problem is. The tiler is claiming that it’s the shower base moving, but I know that the plumber fully supported it before installation and set it with polyurethane/sikaflex as per instructions.

Can any of you tilers suggest an answer to what has happened? I obviously need to rectify the problem, but I’m equally concerned that this problem doesn’t happen in the future.

Thanks in advance for your help.

 

[Tile Marble Granite]

You can send us some good pictures. That would help!

 

[Dylan G]

We have had a similar issue. We found that the waterproofing that was being used was letting go. When the tiles were pulled up the waterproofing was peeling straight off the base.

 

[Dylan G]

We have had the same issue with these bases. We did a test with a fresh base and tried some different waterproofing products and the one that the tiler had been using was bubbling like a reaction to the fibreglass.
When the tiles have been pulled up on these bases the waterproofing just peels off with the tile. We have now changed waterproofing product to hopefully be the difference.

 

[Dylbag23]

We have had this issue just recently with multiple bases also. We did a test of the membrane we have been using and used others to compare on a new base. The waterproofing we had been using bubbled up and peeled straight off the base. The other products didn’t.

The bases we have removed tiles from all peeled the membrane up with ease. That’s what we have put the issue down to!

 

[Melbourne Builder]

Thanks guys. I’ve had someone else come out and look at the tiling: I think that these specific bases must have a bit of flex in them (despite being fully supported) much like a poly marble base does and that’s why the grout is cracking. I am going to get the grout taken out and epoxy grout put back in. Will let you know how it goes.

 

[Tile Marble Granite]

When the grout is cracking at the base of the shower tray that alone tells you a lot about the job. You are pointing the finger to the wrong guy and an epoxy grout job will not cure the error. You will still get the cracks down the road. Good luck!

 

[Floyd*]

Thanks guys. I’ve had someone else come out and look at the tiling: I think that these specific bases must have a bit of flex in them (despite being fully supported) much like a poly marble base does and that’s why the grout is cracking. I am going to get the grout taken out and epoxy grout put back in. Will let you know how it goes.

How did you go with the epoxy grout? I have had similar problems with universal shower trays and the tiler has recommended using epoxy grout as well. He also suggested screwing down the base during installation, because he believes their is micro movement in the base causing the cementious grout to crack and allowing water to get under the tile causing the squishy problem. I have followed the specs from Universal about using Sikaflex to glue down and putting weights on the base. I'm not sure about screwing it down?? Have you had any luck working out the cause of this problem? Cheers

 

[Melbourne Builder]

How did you go with the epoxy grout? I have had similar problems with universal shower trays and the tiler has recommended using epoxy grout as well. He also suggested screwing down the base during installation, because he believes their is micro movement in the base causing the cementious grout to crack and allowing water to get under the tile causing the squishy problem. I have followed the specs from Universal about using Sikaflex to glue down and putting weights on the base. I'm not sure about screwing it down?? Have you had any luck working out the cause of this problem? Cheers

Hi Floyd - so, in the end, I got a re-grouting company (Save & Seal)to remove all the grout and re-do with epoxy. On one of the jobs, where one of the tiles had reasonably significant squishy movement, they injected an epoxy (?) glue underneath. It seems to have done the trick: I’ve had no further call backs to either job (touch wood!) so it seems as though epoxy grout could be the viable solution when using these shower bases.

I’m still unsure as to exactly what causes the movement. Most of the grout cracking seems to happen around the floor waste, so maybe there is a weakness at this point? We followed the install instructions to the letter and infact ended up fully supporting one of the bases, so there must just be a natural flex within the base. Screwing it down might help, (as it does when screwing Scyon Secura flooring down) as it ensures the polyurethane/Sikaflex adheres fully. Thinking on it - from memory, the installation instructions calls up putting weight on all four corners of the base, while the adhesive goes off. Maybe it’s best to ensure that the centre of the base is also fully weighted during the curing time.

I’m not sure if I’ll use these shower bases again. They’re a useful product when installing a walk in shower on top of existing posi-joists, where the joist cannot be cut down or altered. I guess the only option in this case, is to have a small hob or step up - unless anyone has another suggestion?

Good luck Floyd

 

[Tile Marble Granite]

Hi Floyd - so, in the end, I got a re-grouting company (Save & Seal)to remove all the grout and re-do with epoxy. On one of the jobs, where one of the tiles had reasonably significant squishy movement, they injected an epoxy (?) glue underneath. It seems to have done the trick: I’ve had no further call backs to either job (touch wood!) so it seems as though epoxy grout could be the viable solution when using these shower bases.

I’m still unsure as to exactly what causes the movement. Most of the grout cracking seems to happen around the floor waste, so maybe there is a weakness at this point? We followed the install instructions to the letter and infact ended up fully supporting one of the bases, so there must just be a natural flex within the base. Screwing it down might help, (as it does when screwing Scyon Secura flooring down) as it ensures the polyurethane/Sikaflex adheres fully. Thinking on it - from memory, the installation instructions calls up putting weight on all four corners of the base, while the adhesive goes off. Maybe it’s best to ensure that the centre of the base is also fully weighted during the curing time.

I’m not sure if I’ll use these shower bases again. They’re a useful product when installing a walk in shower on top of existing posi-joists, where the joist cannot be cut down or altered. I guess the only option in this case, is to have a small hob or step up - unless anyone has another suggestion?

Good luck Floyd

Time will tell. Good luck!

 

[Floyd*]

Hi Floyd - so, in the end, I got a re-grouting company (Save & Seal)to remove all the grout and re-do with epoxy. On one of the jobs, where one of the tiles had reasonably significant squishy movement, they injected an epoxy (?) glue underneath. It seems to have done the trick: I’ve had no further call backs to either job (touch wood!) so it seems as though epoxy grout could be the viable solution when using these shower bases.

I’m still unsure as to exactly what causes the movement. Most of the grout cracking seems to happen around the floor waste, so maybe there is a weakness at this point? We followed the install instructions to the letter and infact ended up fully supporting one of the bases, so there must just be a natural flex within the base. Screwing it down might help, (as it does when screwing Scyon Secura flooring down) as it ensures the polyurethane/Sikaflex adheres fully. Thinking on it - from memory, the installation instructions calls up putting weight on all four corners of the base, while the adhesive goes off. Maybe it’s best to ensure that the centre of the base is also fully weighted during the curing time.

I’m not sure if I’ll use these shower bases again. They’re a useful product when installing a walk in shower on top of existing posi-joists, where the joist cannot be cut down or altered. I guess the only option in this case, is to have a small hob or step up - unless anyone has another suggestion?

Good luck Floyd

Thanks heaps for your response. I will go the epoxy solution, but the client wants to make sure there will be no squishy movement, so I will remove a couple tiles to investigate.
I always remind the tiler to trowel his glue in the direction of the puddle flange but he says sometimes he has to put blobs of glue near the waste to achieve the height he needs. I think once to grout cracks and water gets under the tile its hard for the water to get to the puddle flange which causes this squishy effect.
I'm still puzzled about the movement as I also fully support and glue down per instructions. I have had this problem with the centre waste and linear channel bases. I am also wondering if its the glue the tiler uses??
I agree, they are very convenient but I might need to go back to screeding.
Thanks, much appreciated.

 

[Melbourne Builder]

Thanks heaps for your response. I will go the epoxy solution, but the client wants to make sure there will be no squishy movement, so I will remove a couple tiles to investigate.
I always remind the tiler to trowel his glue in the direction of the puddle flange but he says sometimes he has to put blobs of glue near the waste to achieve the height he needs. I think once to grout cracks and water gets under the tile its hard for the water to get to the puddle flange which causes this squishy effect.
I'm still puzzled about the movement as I also fully support and glue down per instructions. I have had this problem with the centre waste and linear channel bases. I am also wondering if its the glue the tiler uses??
I agree, they are very convenient but I might need to go back to screeding.
Thanks, much appreciated.

You could be right regarding the retention of water at the puddle flange - this seemed to be the case on one of my problem shower bases - there was water underneath a couple of days after use. I wonder if it's worth putting the glue injection under the moving tiles rather than having to remove them - it certainly seemed to stiffen things up on mine?

I suppose the upshot is that it could be caused by many different things, but I'm not sure if the headaches are worth the convenience!

 

[Matthew7]

Hi Floyd - so, in the end, I got a re-grouting company (Save & Seal)to remove all the grout and re-do with epoxy. On one of the jobs, where one of the tiles had reasonably significant squishy movement, they injected an epoxy (?) glue underneath. It seems to have done the trick: I’ve had no further call backs to either job (touch wood!) so it seems as though epoxy grout could be the viable solution when using these shower bases.

I’m still unsure as to exactly what causes the movement. Most of the grout cracking seems to happen around the floor waste, so maybe there is a weakness at this point? We followed the install instructions to the letter and infact ended up fully supporting one of the bases, so there must just be a natural flex within the base. Screwing it down might help, (as it does when screwing Scyon Secura flooring down) as it ensures the polyurethane/Sikaflex adheres fully. Thinking on it - from memory, the installation instructions calls up putting weight on all four corners of the base, while the adhesive goes off. Maybe it’s best to ensure that the centre of the base is also fully weighted during the curing time.

I’m not sure if I’ll use these shower bases again. They’re a useful product when installing a walk in shower on top of existing posi-joists, where the joist cannot be cut down or altered. I guess the only option in this case, is to have a small hob or step up - unless anyone has another suggestion?

Good luck Floyd

you should try Multipanel pre formed shower bases. I get mine through Bowens and are really easy to work with. They are 25mm so you don’t need to touch the joists. They are glued and screwed down to stop movement. And the tile adhesive manufacturers have all done testing and provided specs so there is good adhesion. Plus they do custom sizing and are approx $100 cheaper!