Moisture resistant plasterboard primer

[ross94]

Hi, i asked a question some time ago about overtiling, now finally having the time i have decided to just do it properly and strip off the originals and start again.

I plan to fix the tiles to green moisture resistant plasterboard and I am just wondering if the boards need to be primed with something like sbr bal bond before i start or will it take the Weight without a primer?
The new tiles will be 400x250 ceramic.
Thanks

 

[JaimieH]

I always prime everything before tiling. Acrylic tilers primer or SBR will be fine.

 

[ross94]

Thanks, i may get shot down for saying this but to keep the cost down could i get away with regular plasterboard and bond it with sbr bal bond or is it best to stick with moisture resistant?

This may be a short sighted view but providing i will be using good quality trade adhesive and grout (bal) which I have made sure is suitable for a power shower, providing the whole area is well grouted is there any reason why a normal plasterboard substrate wouldn't work?
Thanks

 

[dontbelieveawordofit]

normal and moisture resistant will work fine (at your own risk) and youll be wasting your money priming bare board.

 

[JaimieH]

Grout allows water to soak through to the substrate so you really need to tank the plasterboard after priming anyway, whether it's moisture resistant or normal so it won't make that much of a difference. Weight limits for all unskimmed plasterboards are 32kg sqm which is plenty more than the weight of your ceramic tiles and adhesive. The other option is to use construction boards like Marmox etc. These have much higher weight carrying capacities, are fully waterproof and just the joints and screw heads need taping. The cost may be slightly higher but it is a better option in my opinion especially with a smaller ceramic tile and a power shower.

 

[ross94]

Grout allows water to soak through to the substrate so you really need to tank the plasterboard after priming anyway, whether it's moisture resistant or normal so it won't make that much of a difference. Weight limits for all unskimmed plasterboards are 32kg sqm which is plenty more than the weight of your ceramic tiles and adhesive. The other option is to use construction boards like Marmox etc. These have much higher weight carrying capacities, are fully waterproof and just the joints and screw heads need taping. The cost may be slightly higher but it is a better option in my opinion especially with a smaller ceramic tile and a power shower.

Hi, sorry for the late reply, i have decided to go for regular plasterboard which i will bond and tank, looking around it seems moisture resistant plasterboard is not that much better than normal plasterboard besides costing more.

One question i take it i apply the sbr bal bond first before the tanking?
Thanks

 

[lostinthelight]

Some tanking kits come with primer so check first.

 

[dontbelieveawordofit]

Grout allows water to soak through to the substrate so you really need to tank the plasterboard after priming anyway, whether it's moisture resistant or normal so it won't make that much of a difference. Weight limits for all unskimmed plasterboards are 32kg sqm which is plenty more than the weight of your ceramic tiles and adhesive. The other option is to use construction boards like Marmox etc. These have much higher weight carrying capacities, are fully waterproof and just the joints and screw heads need taping. The cost may be slightly higher but it is a better option in my opinion especially with a smaller ceramic tile and a power shower.

‘grout allows water to soak through to the substrate’ ? really?
if that was the case every installation ive ever done including on solid plastered substrate would be rotten by now.
complete nonsense.

 

[dontbelieveawordofit]

this forum never ceases to amaze me . people obviously affiliated to marmox no more ply bla bla bla.
tiles and grout are waterproof . if you get water escaping behind your tiles or under your tray youv’e f&@ked it up and the damage is done regrdless what fancy brands youve got behind them.

 

[JaimieH]

Thanks bennymultifinish, that's helpful...... only epoxy grout is waterproof and impervious to water. All cement based grouts allow water to soak into them, why do you think the grout changes colour when it gets wet? How many swimming pools have you seen which have been lined with plasterboard before tiling and grouting with cement based products?......and in case you're sat there scratching your head the answer is none. I agree that most of the time a correctly tiled and grouted wall in an average bathroom might not necessarily damage the wall behind but why put all your eggs in one basket? If you can waterproof the substrate when you have the chance for very little extra cost and effort why wouldn't you? At least then if at some point in the future you notice that either your silicone has debonded, a tile has cracked or a couple of grout lines are cracked you would probably just be able to sort out the problem without having to replace all the wall underneath. I'm not affiliated to any products but I'm hardly going to recommend something that I either don't think is very good or I've not used before. And what amazes me about some forums is that there's always an ill informed gobshite who think they know it all and give out incorrect advice to people who simply need of a bit of help. I'm glad I'm not one of your customers. I'll await a weighted response or alternative argument from you about this.....but I doubt I'll get it.

 

[dontbelieveawordofit]

you lost your weighted response when you compared a bathroom installation with a plasterboard exterior pool.
“gobshite” with over 80 installations and one call back to a lady who bleached the life out of her silicone.
oh and thats 80 bathrooms 150 kitchens
hundreds of whole house skims ceilings
external renders etc etc.
ive used them all nmp marmox wedi .
correctly installed on pb tiles and grout will do the same job.

 

[dontbelieveawordofit]

I agree that most of the time a correctly tiled and grouted wall in an average bathroom might not necessarily damage the wall behind

see, you could have kept it civil.

 

[JaimieH]

Sorry bennymultifinish, I apologise.

 

[dontbelieveawordofit]

me too love u. x

 

[JaimieH]