paint problem on newly skimmed walls

[andymarshal]

Hi, we just had the downstairs of our house boarded and skimmed. We were doing the kind of sealer coat (watered down emulsion) and we noticed there are runs in the plaster ie like something is spilt on it. It looks like coving glue or something like pva. Anyway the emulsion wont cover it - it keeps showing through. Is the anything i can do or do i have to scrape it of ?

I dont want to scrape it beacuse i may damage the plaster.

Cheers
Andy

 

[Zampa]

It could be slurry from the plastering too

Whether you scrape it off or sand it you will end up marking the wall somehow...buts its better to do it now then when the wall has a couple of coats on it.

Try scraping it off and the lightly sanding it

If it damages the wall then give it a light fill

 

[Third_Eye]

What type and make was the emulsion ? How much did you thin it down by ? How many coats have you given it ? Has coving been applied ?

 

[andymarshal]

What type and make was the emulsion ? How much did you thin it down by ? How many coats have you given it ? Has coving been applied ?

I was using dulux trade matte, thinned about 35%, gave it 2 coats (it covered fine everywhere else) and yeas there is coving up.

Andy

 

[Third_Eye]

You have overthinned your Dulux Trade Matt for first coat and second coat. This is probably the problem in terms of the the bits showing through (lost its hiding power). What you need to do is coat all your surfaces again but only thin down by 10% (at the most) with new emulsion. The most Dulux Trade Matt is to be thinned down is 25% (for porous surfaces) and if thinned down more than that, then you are creating short term & long term problems for your surfaces.

 

[andymarshal]

You have overthinned your Dulux Trade Matt for first coat and second coat. This is probably the problem in terms of the the bits showing through (lost its hiding power). What you need to do is coat all your surfaces again but only thin down by 10% (at the most) with new emulsion. The most Dulux Trade Matt is to be thinned down is 25% (for porous surfaces) and if thinned down more than that, then you are creating short term & long term problems for your surfaces.

Hi, thanks for the reply. The second coat was only slightly thinned down and most of the wall id covered its just these runs which wont take the paint. Its kind of like trying to paint a plastic bag it just doesnt work on these runs.

Andy

 

[ABN]

Had my wall/ceiling plastered recently and had a similar problem. Seemed that the plasterer applied what seemed like PVA glue all around the join between the ceiling and the walls.

Sure enough the first thinned coat did not take at all well on the PVAed areas. Applying a second and third coat carefully just to those areas did stick well enough for the final coats to fully cover.

 

[andymarshal]

Had my wall/ceiling plastered recently and had a similar problem. Seemed that the plasterer applied what seemed like PVA glue all around the join between the ceiling and the walls.

Sure enough the first thinned coat did not take at all well on the PVAed areas. Applying a second and third coat carefully just to those areas did stick well enough for the final coats to fully cover.

Ok mate i will give that a try. to be honest i think it is pva glue. I was going to scrap it all off but i wil try that first.

Andy

 

[Growler]

Had my wall/ceiling plastered recently and had a similar problem. Seemed that the plasterer applied what seemed like PVA glue all around the join between the ceiling and the walls.

Sure enough the first thinned coat did not take at all well on the PVAed areas. Applying a second and third coat carefully just to those areas did stick well enough for the final coats to fully cover.

Ok mate i will give that a try. to be honest i think it is pva glue. I was going to scrap it all off but i wil try that first.

Andy

I've had this problem.
It is possible to wash it out of the affected areas but you've got to keep at it.
Time, patience and elbow grease did it for me.

 

[Third_Eye]

Yes, it is more than likely that PVA has made contact with new plaster. However, your first coat "andymarshal" has been overthinned, therefore creating a loss of hiding/covering power. The reason the emulsion is not covering the PVA areas as good, is cause they are less porous. Also, the minute anyone overthins emulsion, then they lose any rights over the paint makers, should anything go wrong. As for PVA makers they do not recomend to be used in a painting process. The thing about PVA is knowing where and when it can be used.