Tiling onto plasterboard

[Coogie]

Hello,

I am building a shower into an enclosure in my bathroom -

Can I tile straight onto the grey plasterboard, or do I need to prep it in any way first?

Thanks,

Nick.

 

[Nestor_Kelebay]

You CAN tile onto non-waterproof plasterboard, but I wouldn't recommend you use a non-waterproof plasterboard in a wet area like a shower. That's cuz if it gets wet for any reason (like a single cracked grout line letting water in), it looses it's rigidity, and then the tiled board won't have the rigidity to prevent other grout lines from cracking, and you end up with a snowball rolling down hill; the more water that gets in, the more grout lines that crack and the more grout lines that crack the more water that gets in.

Pop down to any of the plasterboard wholesalers in your area and see what they recommend for wet areas like showers. You should be able to find cement based boards and gypsum based boards with treated cores that strongly repel water (not just resistant to it).

If you're dead set on using a non-waterproof plasterboard in a shower, at least do this: Use a V notched trowel to spread a waterproof mastic all over the area that will be exposed to moisture and allow that mastic to dry. Now, use the non-notched edge of the trowel to fill in those trowel ridges with more mastic and allow that to dry, thereby effectively putting a layer of waterproof mastic up over that non-waterproof plasterboard. Then, tile over that.

But, if you ask me, you're much better off using a cement based thin set mortar to set your tile over a waterproof board than using either regular plasterboard or any mastic.