Extending bath tiles for shower over it

[roundthebend]

Hi

Our bath has sufficient tiles around it for use as a bath, however we'd like to install a shower over it. We can get more of the same tiles easily.

My assumption is that the walls are currently constructed with standard plasterboard which the bath tiles are adhered to using a water resistant adhesive and grout.

My simple plan was to extend the height of the tiling to the ceiling, but on considering this I suspect that the plasterboard wouldn't be ideal so I'd be better tanking the area. However, I assume I couldn't tank the board behind the existing tiles.

So, really I'm looking for options (if any) to achieve a shower over the bath without having to remove the existing tiles to improve waterproofing.

My latest thought is that I'd probably need to use a plastic sheet material over the tiles to create the waterproof cubicle. Of course, that might look terrible hence why I'm asking for other ideas.

Kind Regards

 

[Karis]

Do you know for a fact its plasterboard or plastered block work? I wouldn’t bother tanking the new tiled area, no point as the tile base is only as good as the weakest link which will be the current tiled area. Just tile up for your bath/shower & enjoy. It should last at least 3 years if you use quality tiling materials but you may well get more. If it fails, strip it all back & do it properly but you will at least had some use from it!

 

[vv2806]

If it is a more permanent solution (not just for the next few years), I would knock down the existing tiles and would do a proper job. Tiling is messy anyway, so knocking down the old tiles wouldn't complicate the things too much.

 

[Karis]

A “more permanent solution” will involve removing the old tiles & treating/replacing your current tile base with a more suitable backer base, if required. From your initial post, you seem to want minimal work & retain your original tiles (not ideal). Stripping everything back & starting again could involve considerably more work & expense, depending on what you currently have under the tiles, if it’s just crap plasterboard then a more permanent & “shower proof” solution will involve considerably more work, materials & expense.

You need to decide if you want a “quick fix” on what you currently have (2-5 years) or if your going to start again from scratch & have something that will last 10+ years which is not really cost effective unless you doing a complete bathroom refurb & replacing everything.

 

[roundthebend]

Thanks, great replies.

Any thoughts on Mermaid boards or similar PVC over the existing tiles?

 

[Karis]

I’ve never used panels but it’s down to personal preference really. They advise they can be fitted over existing tiles & serve a purpose but I would go for a quality tile finish every time.

 

[vv2806]

A friend of mine used them around the bath/shower area because the tiles there were literally falling off. The whole bathroom needs to be refurbished but this is a cheap temporary solution. Easy to install and would serve its purpose until somebody decides to refurbish the house.

 

[roundthebend]

I asked the building company to find out what boards they had used in the bathroom. The message I got from the Site Manager says "Normal boards used because they were skimmed. No need to use moisture boards."

So, given that the plaster skim is now painted with magnolia emulsion, I figure that I need to use a decent primer at the very least - I have some Ultra branded stuff in an orange container from a previous job. Or, should I be scoring the surface with deep hatching to give a better key for the adhesive?

 

[Karis]

I asked the building company to find out what boards they had used in the bathroom. The message I got from the Site Manager says "Normal boards used because they were skimmed. No need to use moisture boards."

Unfortunately that’s what most site managers/builders will tell you but it’s not ideal, they are only interested in maximising profit. Moisture Resistant plasterboard is a far better bet in bath/shower rooms & kitchens & is the recomended product of board manufacturer's even if part plastering. Using plasterboard in a wet area is the cheap option & skimming it will make little difference & unless it’s tanked will have a limited life span, I’ve had to replace plasterboard in wet areas as little as 3 years old on some renovations as it’s completely disintegrated under the tiles. Much better option is to use a waterproof backer board in wet areas but, again, that’s rarely the cheap “Builder” option on estates & commercial builds.

So, given that the plaster skim is now painted with magnolia emulsion, I figure that I need to use a decent primer at the very least - I have some Ultra branded stuff in an orange container from a previous job. Or, should I be scoring the surface with deep hatching to give a better key for the adhesive?

What are you planning to fix, tiles or panels? If you’re still planning to use panels you need to know their weight & follow the manufacturer’s instructions fro prep & installation. The adhesion of tiles or panels will only ever be as good as how well the paint is stuck to the walls, if paint adhesion is suspect it will just pull the paint off the wall so you will to get underneath the paint. No idea what your left over stuff is or if it’s suitable.

 

[roundthebend]

OK, thanks.

If tiling.....
With the paint being emulsion, I imagined that the primer and adhesive would soak into it and through to the plaster skim giving reasonable adhesion. Of course, straight onto MR board would be preferable but isn't really an option - if that's what is required, then I'll cancel the whole project for the time being.

If using panels.....
I imagined that these would be fitted with screws into decent plasterboard plugs. In any case the panels are PVC so would be lighter than tiles.

I'll find the leftover primer I have and check the info. It was bought in a local tile retailer (Peterborough/Kettering Tile Centre) which has now been taken over by Topps. I think this is the stuff - http://www.ultratileadhesives.co.uk/product.jsp?productID=15

It's interesting how you say that "...skimming it will make little difference..." which implies it might slightly improve things. I thought skimming would make it worse.

I'll inquire about whether it is tanked. I suspect not.

 

[Karis]

If tiling.....
With the paint being emulsion, I imagined that the primer and adhesive would soak into it and through to the plaster skim giving reasonable adhesion.

Er no, it doesn’t work like that. As I said the tile adhesion will only ever be as good as the adhesion of the paint to the plaster. Even plaster has limitations & is not ideal as a tile base if you’re proposing large/heavy tiles. Basically tiles over 8mm thick are likely to be too heavy.

Of course, straight onto MR board would be preferable but isn't really an option - if that's what is required, then I'll cancel the whole project for the time being.

That would be ideal but MR board in wet areas should still be tanked if you want it to last. Tile backer boards are much more suitable.

If using panels.....
I imagined that these would be fitted with screws into decent plasterboard plugs. In any case the panels are PVC so would be lighter than tiles.

It depends on the panels, some are quiet thick & can be heavy.

I'll find the leftover primer I have and check the info. It was bought in a local tile retailer (Peterborough/Kettering Tile Centre) which has now been taken over by Topps. I think this is the stuff - http://www.ultratileadhesives.co.uk/product.jsp?productID=15[/QUOTE]
It’s an acrylic primer/sealer but can also be used as an additive to cheaper, non polymer modified adhesives to increase flexibility & bond strength. Again, adhesion will only ever be as good as the bond of whatever your sticking it on to whatever is underneath.

It's interesting how you say that "...skimming it will make little difference..." which implies it might slightly improve things. I thought skimming would make it worse.

Standard plasterboard turns to mush pretty quickly when exposed to water/moisture; a plaster skim will help with water penetration but will only delay the inevitable once water gets under the tiles.

I'll inquire about whether it is tanked. I suspect not.

So do I.