Strange Texture - New Plaster - Any Ideas??

[nick1903]

Hi. I've had a lathe & plaster wall skimmed. The plasterer did a great job, it felt really smooth. The plasterer recommended a coat of B&Q plaster sealer then on with the paint, which I did. I put on 2 coats of Leyland white contract matt paint. The paint looked really blotchy and had areas where is almost looked like it has run (which it hadn't).

I then gave it a sand, wiped down the dust with a damp sponge, then put on 3 coats of Dulux timeless Classic Antique map matt paint. The result is terrible! It has a raised texture in places that resembles fibreglass (see photos). The texture is very hard and difficult to sand down. I thought it might be a reaction of the paint with the plaster?? It's not over the whole wall but appears in patches.

The plasterer is going to re-skim the worst wall which gets direct sunlight (the sun really highlights the problem) but I just can't understand what went wrong. Has anyone seen this type of texture before with new plaster?

Thanks
Nick

Untitled

• nick1903
• 29 May 2014
• 2

Untitled

• nick1903
• 29 May 2014
• 2

Untitled

• nick1903
• 29 May 2014
• 2

 

[blightymam]

My guess is that it's down to the plaster sealer - I think that you've used watered down PVA (the B&Q stuff) and that should never be used on new plaster. Your plasterer should be sacked to recommend this, the only thing on new plaster should be a mist coat - watered down matt emulsion.

Sorry!

 

[nick1903]

I have a feeling it's the sealer too. This is the B&Q stuff http://www.diy.com/nav/build/buildi...aster-Sealer-Clear-2-5L-9252884?skuId=9260583

 

[blightymam]

I've been thinking about this a bit today while out gardening (yes, I need a life, ha). We've just had plasterer number 4 finish a room and he used a large brush as part of his plastering technique. Not a technique I've seen before, but I remembered today and went and read about it. Apparently it can be used before the final smooth bit, to knock off any loose bits of plaster (I think I read that right? Am sure someone will correct me!)
..... I wonder if your plasterer basically just hasn't finished the job? Did you apply the PVA with a brush yourself? It does look like random brush marks all over.
I would ask him to do the lot again, not just the one that has the most light on..

 

[sparkwright]

How long was the new plaster left for before the sealer was put on? And how long between the sealer and the first coat of emulsion?

Did you use brush or roller?

Certainly a very interesting pattern, a pattern you couldn't achieve if you wanted to.

You say the worst wall gets re-plastered, if it's that bad everywhere you should get him to do the lot. It would seem that sealer is to blame.

 

[ran1]

Interesting.
I don't see any advantage of using a plaster sealer under paint. I do use a special one which acts as a vapour barrier from time to time tho'.

A thinned coat of an emulsion containing no vinyl should be applied to new plaster then followed with 2 top coats of choice.

I doubt the B&Q sealer contains PVA and is probably a formaldehyde base solution to allow for easy penetration.

It sounds like the sealer had done its job. The marks could be where your sandpaper cut through the sealer and left tiny channels & pockets of plaster dust, which went on to bind with the topcoat

The grooves of dust would cause the paint to dry at differrent rates and the problem may have been made worse by using a roller. I'm unsure if this classic range is similar to the endurance range but endurance can be a pain when rolling (1st coat)when the acrylics start to cure.

Good luck

 

[nick1903]

The plan was to use a thinned coat of emulsion until the plasterer insisted that I use this sealer. I think you could be onto something ran1 as the shape and direction of the lines/texture could be explained by a circular sanding motion.

The plaster was left to dry for 2 weeks I think (it had completely discoloured by that time and it was just a thin skim remember). Sealer put on with a brush as directed by instructions (in up and down strokes - not all over the place like the texture appears) and the paint put on with a roller, cut in with a brush. A couple of days between applying the plaster sealer and the paint - the instructions said 4 hours if I recall.

 

[MidsTW]

I'm more inclined to say sandpaper too.... What grade was it?

 

[oldschoolmechanic]

I doubt that is due to sanding (look closely at your first pic).

Try reposting the question into the Plastering and Rendering forum ?

//www.diynot.com/forums/viewforum.php?f=32

 

[joe-90]

It's been overbrushed as it was drying. Simples. If you keep on brushing when you should walk away and leave it it will look just like that.

 

[nick1903]

Joe-90: Do you mean when I was brushing on the plaster sealer? The stuff is like water and goes on in seconds with one brush stroke. I did up and down strokes - not left to right which some of the marks are. I used a roller for the paint application.

I used Oakey Liberty Green Extreme Sandpaper Fine Pack of 8 - says 120 coarse.