How Flat Does A Wall Need To Be For Tiling

[ck1]

I've just had some new plasterboard put up on my bathroom walls ready for tiling, there seems to be a lot of lipping between the sheets though which I wasn't expecting to see. Before I complain, is this normal, and is there an allowable amount of lippage in order to be able to tile over?

[The Builder]

Plasterboard should always be as "flush" as possible Ck.
Was it nailed onto timber studwork, or glued on?

[Old_Geezer]

As flat as possible. Otherwise you need skill to judge the adhesive needed to even the fronts of the tiles out. How much is "a lot" of lipping" ?

[ck1]

It was nailed on, I asked the guy and he said there's about 5mm of adhesive to go on so it's not a problem...

[ck1]

But 5mm of adhesive sounds like a hell of a lot!

[AuntPollyGrey]

Sounds dodgy to me - plasterboard should be flush and yes I'm not an expert on tiling but 5mm adhesive for WALL tiles sounds a bit generous. Seems to me like your tiler is tiling over bad workmanship - never a good idea.

[The Builder]

I don't see how it can be so far out on studwork.
Are we sure he hasn't used different thickness plasterboard? ;o)

Depends on the size of tiles. Modern preference is for those dirty great big 300mm x 600mm ones.
Now, they often need even more than 5mm to stop them rocking.

[ck1]

The explanation was that the edges of the plasterboard are bevelled, so if you put a bevelled edge against a cut board there will be a lip. Kinda makes sense, it's hard to argue when you have no idea about the intricacies of plasterboard!

[The Builder]

Oh.......... is that all it is Ck ;o))))

Not good practice usually (when plastering), but I can assure you it will make no difference at all for tiling.