Any Paint Experts?

[bobscarle]

I am just starting to decorate the bathroom and have a problem with the existing paint. The room was partially re-plastered about 8 years ago when we extended. I used, I think, Homebase Kitchen and Bathroom emulsion to paint the walls.

The problem I have is the paint has not stuck properly to the plaster. It peels off in great long strips. I do not see how it would be possible to paint over it and certainly not tile over it. I applied the paint directly to the new plaster originally and I think that was my mistake. Now I know that this sort of paint does form a skin but I would have thought it would have adhered to the wall a little better.

So, the question is, once the old paint has been removed, what do I put on the walls, a) behind the new tiles and b) under the new paint? I intend to use ordinary emulsion this time.

For the painted areas I thought of applying a coat of watered down cheap emulsion to seal the plaster. For the tiled area I thought about using PVA, again watered down. Any comments on this would be appreciated.

Bob

 

[TonyW]

So, the question is, once the old paint has been removed, what do I put on the walls, a) behind the new tiles and b) under the new paint? I intend to use ordinary emulsion this time.

For the painted areas I thought of applying a coat of watered down cheap emulsion to seal the plaster. For the tiled area I thought about using PVA, again watered down. Any comments on this would be appreciated.

While this is normally associated with new plaster I would suggest:

1. For the painted area. Paint over plaster first with a mist coat (diluted approx 30%) of good quality matt emulsion then follow up with another 2 coats diluting less each time- I believe Dulux Trade Matt emulsion regarded highly

2. For the tiled area I would not use PVA - may prevent tile adhesive adhering properly. In fact why paint there at all?

Cheers
Tony

 

[bobscarle]

Tony

I am not thinking of painting the area to be tiled, but I do need to ensure that the adhesive bonds to the wall properly. We have some existing tiles and these are coming away from the wall, maybe failing for the same reason as the paint. For this reason I assumed I would have to seal the plaster.

I agree with you about the painted areas and I think I will dilute some emulsion and paint that on. 3 coats?

Bob

 

[cornucopia]

hello i'm a dulux select deccy with a few awards etc

because you didnt mist coat originally the homebase paint hasnt adherd to the plaster, you have two choices- strip the old emulsion with a steamer or heavily abrade the walls,idealy with a power sander with 40 or 60 grit, this will remove any flaking areas and whats left will be good enough to paint over- then you will have to feather in the edges created using some fine surface filler, then apply a problem solving basecoat- zinnser bin for very small areas- zinnser all coat or 1-2-3 for larger areas. then i would apply dulux trade's diamond eggshell to ceiling and walls.
if you decide to steam it of- make good the walls, abrade with some 120 then apply zinnser 123 or allcoat or mist coat 10% with retail dulux brand or 15 to 20% with dulux trade vinyl matt or 10% with dulux trade supermatt. then apply dulux trade diamond eggshell as before.
if you need to tile over this homebase problem areas- i would scratch the surface up -2mm deep then apply a pva soloution of 1part pva to 3 parts water to gurantee a good bond.

hope this helps
george

 

[jasonB]

As Tony says for the painted areas, once all the old paint is removed apply a mist coat, this should have been done originally then you would not have the problem.

You should not really need to seal the plaster unless it was over polished or now has a dusty surface. To be on the safe side and to also get a longer working time apply an acrylic sealer such as BAl APD. Definately do not use PVA

Use separate adhesive (preferably powdered) and powdered grout, both should be flexible if its onto skimmed plasterboard.

Jason

 

[wizer]

I've had this problem before and did as advised. Stripped as much as I could and then mist coated. It worked well.

 

[Karl]

Definately do not use PVA

Jason

Hi Jason

I thought i'd resurrect this as I have a question which I hope you can answer.

As an alternative to the BAL sealent you refer to, I have used PVA solution (50/50 with water) to seal pretty much any surface prior to tiling (fresh plaster, concrete floors, ply-lined floors). It was recommended by the guy who runs my local tile supply shop. I haven't yet ( [-o< ) had a failure of the adhesive as a result of using the PVA mix, although I only set up on my own 3 1/2 years ago.

So the question - why not use watered down PVA? I do remember one plasterer telling me that the best way to remove old tile adhesive was to use a PVA solution mixed with hot water, but I assumed he was talking balls.

Cheers

Karl

 

[jasonB]

There is a risk of moisture either from the tile adhesive or later when all set water getting in through the grout and making the PVA live again with the risk of the bond failing. The PVA also tends to sit on the surface more than the ADP which soaks in.

BAL specifically don't reccomend it and it will void any gaurantee of their adhesives.

I'll post the full details later when I get back in.

Re removing adhesive, warm water is verygood for removing a lot of ready mixed adhesives, wallpaper steamers work well also but no need for the PVA.

Jason

 

[andrewm]

At the risk of hijacking this thread but since we are discussing bathroom paints I have similar, but different problem with emulsion on bathroom walls. The house was built in 1948 and the original bathroom was painted in an oil based paint in a rather fetching deep cream to the top of the walls and green to the bottom with a darker green ‘dado rail’. It stayed like that until about ten years ago when I replaced the original green suite[1].

The walls were then painted with Dulux kitchen & Bathroom vinyl. Fairly soon afterwards this started cracking and kept cracking until the whole wall was covered by a web of fine cracks. I contacted Dulux and they recommended using their eggshell paint. This was duly done but the same problem occurred. The Crown Decorator Centre recommended sealing with Zinsser 1-2-3 and then applying a vinyl matt but this has cracked as well.

I have variously tried stripping with Nitromors, a wire brush and a hot air gun; the latter doing a great job but for the fact that it lifted the topcoat of plaster as well.

I am about to have another go so any suggestions short of getting the whole bathroom replastered?

Andrew


[1] Actually only the bath and toilet were green by then, the washbasin having been broken sometime in the ‘70s and replaced by a ‘matching’ chocolate brown. But you get the idea.