Paint peeling off walls...

[grubar30]

Hi all,

Can anyone recommend a good paint stripper - one that is preferably non-toxic.

I am in a bit of a renovation crisis at the moment - I have noticed flaking of paint off walls after having completely painted one bedroom. After much investigation, I have come to the conclusion that the previous owner had done a dodgy renovation, in that they didn’t apply any undercoat when painting the unit. Therefore, I was painting over a surface that wasn’t adhered properly.

I now have to remove all layers of paint until I can get back to the original layer (must be 30 years old). After toiling with a scraper for much of today I realised I was getting nowhere fast. I’m thinking some kind of paint stripper might make things easier. But I want to be careful to remove only the loose layers and not the original paint, as this layer seems to be good to work from.

Btw, is a paint stripper the best course of action here? What if the original layer of paint is not conducive to acrylic (water-based) undercoat? If I was to proceed, then this might end up causing flaking again.

George “where do I go from here” Grubetic

 

[Brizzy Boy]

Grubar30,
a question first, what type of wall is it, gyprock, vj, etc.
Regards
John

 

[skater]

There is an undercoat you can buy that goes over any surface, even flaking paint. It's called Zinnser (spelling?). You then paint straight over like normal. Check with your paint supplier if it is suitable in your situation. I have used it several times & have been very happy with the result.

 

[GoAnna!]

How old is the building? You mention 30 years? Is that the age of the building?

 

[grubar30]

a question first, what type of wall is it, gyprock, vj, etc.
Regards

Hi Brizzy boy,
It's Bessa brick. It's been rendered, or whatever they put over the bricks to make it smooth.

There is an undercoat you can buy that goes over any surface, even flaking paint.

Hi skater,
I don't think undercoat would make a difference. Remember, the layer of paint I painted over was loose. So no matter how much I prime/seal/undercoat, all my efforts would prove fruitless as the underlying surface is not bound properly itself. That's why I need to go back to a least a surface/layer that is tight and secure - it's from there that I need to start my painting process.

How old is the building? You mention 30 years? Is that the age of the building?

Hi GoAnna, the building is ~ 30 yrs old.

 

[madmurf]

Hi

I had a similar problem with a ceiling that every time I painted it, 3 months later it would start to peel.
The best solution and easiest is to us a product called Bondcrete.(check spelling)
Mix about spary can cap full of Bondcrete to 4 litres of paint. I have even used this mix to seal brand new plastered walls and Gyprock.
It will tend to give the paint a semi gloss look but treat it as the first coat.

Other wise sanding the complete room back to the plaster and using the correct base paint will work.
What happens with Plastered walls is they tend to add lime to speed up the drying process.

Cheers

 

[MarkR]

Madmurf - bondcrete in paint, now that is genius in it's simplicity ! I've used bondcrete in plaster to hold to flaky rendering or bricks, but will have to remember this one.

Cheers
Mark

 

[grubar30]

The best solution and easiest is to us a product called Bondcrete.(check spelling) Mix about spary can cap full of Bondcrete to 4 litres of paint.

So your saying this Bondcrete stuff will actually seep through the loose layer of paint and bind it to the wall?

Other wise sanding the complete room back to the plaster and using the correct base paint will work.

That's another thing - I tried sanding with an electric sander but that proved ineffective (even with a rough grit).

 

[madmurf]

So your saying this Bondcrete stuff will actually seep through the loose layer of paint and bind it to the wall?

Yep
Scrape all loose material away and sand so edges of the paint are smooth.
If the paint is standard internal paint it seems to work.

Note Once you use the Bondcrete both paint and equipment will begin to harden (takes a few hours) . I usually mix it in the amounts I require to use it in one session of painting. It will wash out in water but will also set in water.


Cheers

 

[Michael Croft]

Hi Guys,

Bondcrete is just a type of PVA glue and will prenetrate only so far as the surface to which it is applied will allow. Use water as a guage, if it beads on the surface so will bondcrete. In other words if your paint is not porous bondcrete won't work. It will bond to the top coat and seal some of the flaking at the edges (works at the margins) but won't stop the lack of adhesion otherwise. Bondcrete or PVA works well for raw concrete/render when used with water based paints.

Taubmans made a product called "bindfix" which was designed to penetrate through old kalsomine (spelling?) paints (caulky feeling) and bind all to the original surface (substrate). Smelt like the carrier was petrol (or a similar solvent) and it worked well. However even this won't work if the topcoat is water tight.

You may be able to score though all your paint work removing the loose stuff in the process and then paint on "bindfix" or equivalent, then resume your painting job. A lot easier than stripping the lot.

All the best, MC

 

[grubar30]

Use water as a guage, if it beads on the surface so will bondcrete. In other words if your paint is not porous bondcrete won't work.

Well said Michael. That was the point I was trying to make. I'll look into the bindfix.

I'll keep at it and let you guys know how it turns out.

 

[depreciator]

There is also one called Prepcoat. I think it's Dulux. I've used it on powdery and flaking walls inside and out and it's been fine.

The last thing you want to do is start using a brush on paint stripper. Most of them require water to wash them off and neutralise the stripper. There is a citrus based one, though, that doesn't have the fumes of the conventional ones.

There is a a great product I used a couple of years ago. It's a stripper that is like a sheet of plastic with one really sticky side. You stick it on, and peel it off. I don't know how many layers it would take off. Maybe only one? I also don't know what it costs. I suspect to do a whole room would be pretty expensive. Specialist paint stores would have this product.

Years ago I tried something when I had a similar problem i.e. previous coat of paint not bonded. I bought some cheap contact paper, peeled of the back, stuck it on the wall, crossed my fingers, peeled it off, and the offending layer of painted came with it. I think I got lucky. If you're in Sydney, I can tell you where you might be able to get some cheap contact paper to test it. The risk with these things is you might damage the good layer of paint below the lousy one. Worth trying, though.

Scott

 

[geoffw]

The last thing you want to do is start using a brush on paint stripper. Most of them require water to wash them off and neutralise the stripper.

Scott

You seem to know a lot about strippers

Once in the distant past I used a heat gun to remove enamel paint from skirting boards- though I suspect that there may be fume problems with that appraoch.

 

[markpatric]

This type of job years ago would have been a real headache but today you can buy products which will penetrate below top coats
Forget paint stripper, forget your average everyday scrapers.
At worst you would use a Scarsten scaper which will strip back to bare easily in the bad spots where actually lifting, I stress if it is lifting in areas this needs to be taken back, I would probably scarsten scape the whole wall lightly fill bind then top coat.
Otherwise fill with cornice cement or similar where needed, apply the OIL or metho or water based zinsser binder (which you can get all from Bristol) then top coats.

 

[Brizzy Boy]

Grubar30,
all the above remedies re bondcrete and bindfix etc are fine, I have a concern as paint will peel or flake off masonery due to moisture. After removing the flakey, peeling paint from the wall I do suggest you coat the wall with bondcrete to seal the wall first. Then undercoat and paint as normal.

regards
John

 

[grubar30]

Thanks for the replies guys. I’ve decided to take the steady approach and scrape back any loose paint, then sand, then apply the undercoat (it’s a sealer/undercoat combo).


Out of interest – why would some portions of the wall be flaking but others not. The flaking parts seem to come off easily but other areas won’t even come off with a scraper. Does this merely mean that their time to flake will come too?

Another question:

Say I want to paint over an oil-based, high-gloss surface (btw, is oil-based paint by nature gloss?) with acrylic paint. Would sanding back the surface (i.e., wall) with rough grit, and then applying an acrylic sealer/undercoat, followed by the acrylic topcoat, be a sufficient preparation process? That is, would this cause the topcoat to adhere properly?

Also, I have architraves which I've stripped back to the bare aluminium. I then applied two coats of acrylic based sealer/undercoat, followed by two top coats of aqua-enamel (an acrylic paint made by Dulux to mimic a hard-wearing enamel paint). I'm wondering, should have I used a primer instead of a sealer? Does it make much difference? I’ve heard that a primer is a layer of paint put down on metal surfaces to enable it to better hold a coat of enamel paint. Is this true?

 

[Brizzy Boy]

Grubar30,
your first question re flaking paint from some parts of the wall easily and other areas not, this why I asked the question re moisture as this is what happens.
Your 2nd question re is oil based pain usually gloss, no oil based paint ranges from flat,semi gloss etc.

3rd painting acrylic over gloss, yes rub back with sand paper, I would personaly use oilbase undercoat, but I feel that acrylic undercaots have improved in quality since I used to be a painter,"but still I would use an oil based undercoat a personal choice". Then it will be fine to apply an acrylic gloss.

4th in regards to the aluminuim architrave I would have used a metal primer first, but I feel that you should not have any hassell in what you have done.

Kind Regards
John

 

[grubar30]

Cheers for the info Brizzy.

With regards to moisture, no there isn't any on the walls.

I feel the peeling/flaking is simply a result of the previous owner painting over an oil-based surface with acrylic, without proper preparation - I don't think she even used an undercoat let alone sanded. Hence, why I'm curious why some areas are peeling and others aren't - and I'm talking about the same space, for example the bedroom wall or the lounge room wall.

Btw, how does the principle of oxidization of oil-based paint work? Does this relate to peeling paint?

Thanks guys.

George

 

[Brizzy Boy]

I follow you now, oilbased paint on wall without preperation then acrylic paint painted over it, this will cause the peeling. I still suggest sealing the walls as others have suggested earlier.

Oxidization is usually a result of exposure to weather, a sign of oxidization is when you run your hand over a painted weather or chamfer board and you get a white powdery colour on your hand or fingers. Best to have the boards repainted before the paint starts to crack due to expansion & retaraction due to weather extremes. Once paint cracks moisture then gets in behind the paint and excelerates the deteriation process resulting in peeling of the paint.

regards
John