Hi folks
I have just primed a freshly plaster skimmed wall(done 2 wks ago) with mapei PRIMER G left it a few hours it has formed a skin over wall but when skin is broken it peels off really easily would not fancy tiling on it.I put it on neat as instructions where a bit vague.Any ideas where i am going wrong?

The plaster may have still been damp after two weeks, the instructions tell you to dilute the product, why did you use it neat?

It read to me like it was only to be diluted for use on dusty floor.do you think thats the cause, plaster looks pretty dry.do you know what the correct ratio is?

If the plaster was polished to much then the primer cannot penetrate properly , so it should have been lightly sanded or a brush over with a stiff brush.

Also applying it too thick can result in it skinning as well... but i will bet on the plaster being over polished or moisture still present.

As Dave said over polished plaster skim. sometimes emulsion paint evens peels off. lightly sand it and dilute primer.

http://www.mapei.it/Referenze/Multim...mer%20G_gb.pdf

Will give it a sanding first.Just checked instructions and it says USE NEAT ON GYPSUM BASED SUBSTRATE??

Originally Posted by Tiling Anorak

Will give it a sanding first.Just checked instructions and it says USE NEAT ON GYPSUM BASED SUBSTRATE??

It don't work neat on anhydrite screed - need diluting about 3:1 or maybe even 4:1 on occasions. Neat it does exactly what you have described.

I always thin out and have never had any problems

Id 4:1 then leave it for 24 hours and use a stronger coat

Just realised it's bal apd I use and they say thin out