Tiling onto new plaster

[John the tile]

Hello,

Just wondered how long after new finish plaster has set can you tile onto it.

ta

 

[david campbell]

usually give it 4-6 weeks depending if it is a skim or a new coat!

 

[enduro]

And it will need priming, not with pva use Bal SBR or similar

 

[doug boardley]

is it onto plasterboard or plaster basecoat?

 

[bitter&twisted]

When u need too as long as its dry lol :smilewinkgrin:

 

[John the tile]

either plasterboard OR backing coat,.

6 weeks, why? I thought skim plasters dried out within a week. On domestic properties I cant see customers beeing to happy if you said it cant be done for 4/6 weeks. Thay will be wanting to get their kitchen or bathroom back to normal??

any comments

 

[doug boardley]

either plasterboard OR backing coat,.

6 weeks, why? I thought skim plasters dried out within a week. On domestic properties I cant see customers beeing to happy if you said it cant be done for 4/6 weeks. Thay will be wanting to get their kitchen or bathroom back to normal??

any comments

a gypsum base coat will retain its moisture far longer than a plasterboard,it breathes moisture!, as a rule of thumb I'd tile skimmed plasterboard after 2 weeks, basecoat and skim probably about 5 weeks before tiling. Ideally tho' I wouldn't plaster onto skim because of the weight bearing (20kgm2) issues.:dizzy2:

 

[John the tile]

sorry doug, i didnt understand wat you meant when you said you wudnt plaster onto skim? did you mean tile onto skim?

so can you explain why a backing coat that still has a bit of moisture in it will effect a tile being stuck onto its top coat?

just trying to get me head round the reasons!

 

[david campbell]

either plasterboard OR backing coat,.

6 weeks, why? I thought skim plasters dried out within a week. On domestic properties I cant see customers beeing to happy if you said it cant be done for 4/6 weeks. Thay will be wanting to get their kitchen or bathroom back to normal??

any comments

would you rather wait or do it twice?

 

[doug boardley]

sorry doug, i didnt understand wat you meant when you said you wudnt plaster onto skim? did you mean tile onto skim?

so can you explain why a backing coat that still has a bit of moisture in it will effect a tile being stuck onto its top coat?

just trying to get me head round the reasons!

yes, that is what I meant!!

 

[doug boardley]

all sorts of reasons golddigger, latent residual moisture being one of them, which will unbond your adhesive, to be honest there's lot's of reasons why not to tile onto fresh skimed plaster..................

 

[mikethetile]

When u need too as long as its dry lol :smilewinkgrin:

no no no

leave a minimum of 4 weeks

 

[John the tile]

ok so basically moisture in the backing coat will make the adhesive unbond. fair enough. but


plasters only 3mm ish thick on boards and old walls e.g unibond and skim - there no moisture left in skim after 3 or 4 days. the old walls and boards suck the water out of the skim. ???


:mad2:

 

[mikethetile]

bb

ok so basically moisture in the backing coat will make the adhesive unbond. fair enough. but


plasters only 3mm ish thick on boards and old walls e.g unibond and skim - there no moisture left in skim after 3 or 4 days. the old walls and boards suck the water out of the skim. ???


:mad2:

if you unibond and then skim the skim can only dry forward

if you tile and grout then the molsture is trapped behind your tiling which can only mean one outcome

4 weeks minimum is reccomended for a reason and thats good enuogh for me and most other people

others try reinventing the wheel at their own peril

its your behind that it will bite if the jobb fails

 

[grumpygrouter]

Though not a plasterer, I also understand that it can take several weeks for the plaster to gain sufficient strength to cope with the loading of tiles, not just being "dry"!