New bathroom project - help needed!

[wrighty208]

Hi all,

I have taken out my existing bathroom suite and ripped off the old tiles (and plaster as it fell off!).

I was going to dot-dab 9.5mm plasterboard onto the brick and breeze block walls ten re-tile the plasterboard.

I'm now worrying the plasterboard adhesive will not be strong enough to hold the plasterboard and tiles once fitted. Also I now know I should use moisture resistant plasterboard in the shower area.

Unfortunetly I have already purchased 9.5mm plasterboard and adhesive.

Will it be ok to use dot-dab normal plasterboard and tile on top? - will the adheasive hold the weight? I will PVA the plasterboard a couple times to waterproof it. Or...should I battern the walls and screw the plasterboard in place - 2" x 1" timber for example?

Thanks for any advise.

 

[User]

I had the same concern so decided on sand cement render in the bathroom

But that was more due to the water issue sand cement render is best for any watery area like bathroom tiles straight on top of that

I would wouldn't PVA the shower area I bought a tub o shower waterproofing kit £43 the PVA apparently becomes "live" when exposed to water like may be in shower area

I'm using normal plasterboard in other shower area with above waterproofer on

My instinct would be that dot and dab is okay cus the weight is pushing downward right but others will know better

 

[Richard C]

I was going to dot-dab 9.5mm plasterboard onto the brick and breeze block walls ten re-tile the plasterboard.

I would never use 9.5mm PB for D&D onto walls even if I wasn’t tiling onto it, it isn’t thick/rigid enough.

Also I now know I should use moisture resistant plasterboard in the shower area.

You should use moisture resistant PB throughout the bathroom & either tank the wet area areas;
http://www.bal-adhesives.co.uk/products/wp1-coating
or use a waterproof tile backer board which is always my preferred option.

Unfortunetly I have already purchased 9.5mm plasterboard and adhesive.

I wouldn’t use 9.5mm board; exchange it for 12.5mm if you can; the adhesive you can keep & use.

Will it be ok to use dot-dab normal plasterboard and tile on top? - will the adheasive hold the weight?

The adhesive is not a problem. Tiling direct onto PB is 32kg sq/m plaster finish is 20kg sq/m. In reality, this can probably be exceeded a little; generally you will be OK unless your tiles are thick & heavy, check the weights.

I will PVA the plasterboard a couple times to waterproof it. Or...should I battern the walls and screw the plasterboard in place - 2" x 1" timber for example?

Do not use PVA in an attempt to waterproof PB, it won’t; its water soluble not water proof & is basically glue! You don’t need to batten unless using tile backer boards & even then, there are ways around this.

You seem to have made several fundamental mistakes already. If you want your new bathroom to last any length of time, my advice would be to read the tile sticky, do some more research in the archive posts, buy the correct materials & use only trade quality flexible adhesive & grout not the cheapo DIY stuff.

 

[wrighty208]

Thanks for all the info!

I've taken some of the advise and purchased aquaboard from Wickes to use all around the bath area.

Should I PVA the Aquaboard before tiling or just tile directly on top?

Also for the remaining plasterboard - same question - should I PVA before tiling?

Thanks

 

[Richard C]

Make sure you brush off any excess dust &, if necessary, give the surface a wipe over with a damp (not wet) sponge. You do not need PVA on either Aquapanel or plasterboard before tiling but tape & seal the joints using a little tile adhesive immediately before tiling; make sure the tile joints don't coincide with any of the board joints.

What tile adhesive & grout are you using

How are you fixing the Aquapanel to the block walls

 

[wrighty208]

Make sure you brush off any excess dust &, if necessary, give the surface a wipe over with a damp (not wet) sponge. You do not need PVA on either Aquapanel or plasterboard before tiling but tape & seal the joints using a little tile adhesive immediately before tiling; make sure the tile joints don't coincide with any of the board joints.

What tile adhesive & grout are you using

How are you fixing the Aquapanel to the block walls

Does it do any harm to PVA plasterboard before tiling?

I have 2 tubs of Mapei MapeGrip Plus Fully Water resistant and showerproof tile adhesive and Wickes Waterproof Tile Grout.

I fixed up the Aquapanel last night using 2x1" Studs screwed into the wall.

I've now hit a turning point where the bathroom is beginning to look like a room again!

 

[Richard C]

Does it do any harm to PVA plasterboard before tiling?

The board manufacturers don’t recommend it & unless the tile adhesive manufacturer does you should not use it; but don’t take my word for it;
http://www.ultimatehandyman.co.uk/tiling/diy_Tiling_Why_not_to_use_pva.htm

I will admit that I have never tested the theory but why waste PVA if you don’t need it!

I have 2 tubs of Mapei MapeGrip Plus Fully Water resistant and showerproof tile adhesive and Wickes Waterproof Tile Grout.

I always use BAL products & personally have not used Mapei although I have heard good reports about it; perhaps others can advise. I have in the past used Wickes tile adhesive for small general tiling jobs on splash backs etc. but I’ve never used it in a bathroom. I have no personal experience of their grout but I think the price might be a clue;
Except for large/heavy wall tiles, I use this;
http://www.bal-adhesives.co.uk/products/white-star
& this for grouting;
http://www.bal-adhesives.co.uk/products/microflex

Decent gear doesn’t come cheap; I wouldn’t want the tiles on one of my jobs coming adrift after 6 months so I don’t experiment & only ever use products & methods I know will work.

 

[wrighty208]

Just seen this stuff :-
http://www.screwfix.com/prods/79333...chen-Bathroom/Dunlop-Shower-Waterproofing-Kit

I've already used aquaboard around the bath but could I have used this stuff on standard plasterboard instead? Or is it worth using it on other areas like around the sink or even rest of bathroom as it gets very humid?

Thanks for all of your advise, it's much appreciated.

 

[Richard C]

Just seen this stuff :-
http://www.screwfix.com/prods/79333...chen-Bathroom/Dunlop-Shower-Waterproofing-Kit
I've already used aquaboard around the bath but could I have used this stuff on standard plasterboard instead?

Yes you could have done & I did say that in my first post. I believe BAL & Dunlop are now one & the same so in all probability, it’s the same product as the link I posted above;
This is the BAL equivalent waterproof kit;
http://www.bal-adhesives.co.uk/products/waterproofing-kit
& the link above;
http://www.bal-adhesives.co.uk/products/wp1-coating
is the same stuff but without the tape.

The problem is that standard wallboard will grow huge amounts of musty smelling mould & eventually disintegrate when affected by moisture. This becomes all too obvious when you strip out a plaster boarded bathroom for refurbishment; the slightest flaw in the tanking will still eventually cause problems. Although some do use standard wallboard & tank, as I said, I will only use moisture resistant as a minimum in bathrooms & tank the wet areas but always prefer to use a waterproof tile backer board on wet areas as it’s guaranteed 100% & the cost difference is negligible when you factor in the waterproofing agent; some will even tank tile boards!

Or is it worth using it on other areas like around the sink or even rest of bathroom as it gets very humid?

It’s not usual or necessary to tank/waterproof other than wet areas in the bathroom but if you use Moisture Resistant plasterboard it’s not necessary. What size is your bathroom? Given that you’ve bought only 9.5mm wall boards, which in my view aren’t suitable for walls let alone tiling onto, I would seriously consider accepting the mistake & go to 12.5mm MR plasterboard. Waterproofing agents are not exactly cheap & using them on standard wall board in the rest of the bathroom may turn out to be more expensive than switching to MR plasterboard!