Paint Bubbling/Peeling External Wall

bystarlight

So I painted the front wall last summer. Weather was hot, not roasting. The wall is about 20 years old and needed a fresh coat of paint. Small bit of peeling in places, but not bad at all.

Here's what I did:

- scraped off the small bit of peeling paint
- washed down wall (water and bit of bleach, as there was a small bit of mould)
- let it dry
- filled cracks and holes (Polyfilla External Filler)
- applied two coats of oil based stabilizing solution (Sandtex)
- let it dry
- then two coats of Dulux Weathershield

It all looked great until December. When the frost came, the paint bubbled, and between the paint and the wall was ice (in the bubbling paint).

Obviously when the ice melted the paint peeled, and peeled much worse than before I painted it. And not only did the paint from last summer come off, but all the paint did. It peeled back to the bare wall, as you can see in the pictures attached.

So what did I do wrong? And what should I do to repair it this summer, so that the same doesn't happen next winter?

Thanks!

irishbuzz

What is behind the wall and how is it finished?

bystarlight

There's nothing behind the wall, just the lawn.

The wall is between the lawn and the road.

Not sure how it's finished.

irishbuzz

Perhaps water is seeping through it from the fair side. Especially if it is a retaining wall.

bystarlight

irishbuzz wrote: »

Perhaps water is seeping through it from the fair side. Especially if it is a retaining wall.

It's not a retaining wall.

karlitob

bystarlight wrote: »

So I painted the front wall last summer. Weather was hot, not roasting. The wall is about 20 years old and needed a fresh coat of paint. Small bit of peeling in places, but not bad at all.

Here's what I did:

- scraped off the small bit of peeling paint
- washed down wall (water and bit of bleach, as there was a small bit of mould)
- let it dry
- filled cracks and holes (Polyfilla External Filler)
- applied two coats of oil based stabilizing solution (Sandtex)
- let it dry
- then two coats of Dulux Weathershield

It all looked great until December. When the frost came, the paint bubbled, and between the paint and the wall was ice (in the bubbling paint).

Obviously when the ice melted the paint peeled, and peeled much worse than before I painted it. And not only did the paint from last summer come off, but all the paint did. It peeled back to the bare wall, as you can see in the pictures attached.

So what did I do wrong? And what should I do to repair it this summer, so that the same doesn't happen next winter?

Thanks!

No expert but I wonder if it’s anything to do with the oil based stabiliser and a water based paint.
How long was it between when the stabiliser and paint was applied?

El_robbo1980

Is/was the wall subject to any efflorescence? Had similar on a wall I painted last year due to the salts coming from the blocks causing the paint to blister and peel.

bystarlight

karlitob wrote: »

No expert but I wonder if it’s anything to do with the oil based stabiliser and a water based paint.
How long was it between when the stabiliser and paint was applied?

I think there was a few days between, but that's my guess too. I just don't know for sure.

bystarlight

El_robbo1980 wrote: »

Is/was the wall subject to any efflorescence? Had similar on a wall I painted last year due to the salts coming from the blocks causing the paint to blister and peel.

Don't think so. Saw no signs of it anyway.

blueskys

Is the other side painted/plastered?

karlitob

bystarlight wrote: »

I think there was a few days between, but that's my guess too. I just don't know for sure.

I think - dangerous I know - that it needed longer to cure before you applied a water based paint. The wall underneath the bubble seems so bare - it’s like the paint didn’t get sucked into the substrate.

If I’m right about that, then no harm done. Prepare the wall, scrape everything back and either use thinned down first coat with 10% water followed by a second coat; or use a primer such as Owatrol EB on your first coat at 50:50 followed by a second coat. I would also use a top quality, 100% acrylic masonry paint. I’m sure weathershield is - I use colourtrend and found it very good.

Finally, the suppliers of owatrol in ireland - Igoe international - are a really good bunch of lads. So helpful and give loads of advice. Google them, send on pics on WhatsApp and you’ll get a great bit of advice.

bystarlight

blueskys wrote: »

Is the other side painted/plastered?

Yes, also peeling in places

bystarlight

karlitob wrote: »

I think - dangerous I know - that it needed longer to cure before you applied a water based paint. The wall underneath the bubble seems so bare - it’s like the paint didn’t get sucked into the substrate.

If I’m right about that, then no harm done. Prepare the wall, scrape everything back and either use thinned down first coat with 10% water followed by a second coat; or use a primer such as Owatrol EB on your first coat at 50:50 followed by a second coat. I would also use a top quality, 100% acrylic masonry paint. I’m sure weathershield is - I use colourtrend and found it very good.

Finally, the suppliers of owatrol in ireland - Igoe international - are a really good bunch of lads. So helpful and give loads of advice. Google them, send on pics on WhatsApp and you’ll get a great bit of advice.

Thanks very much for that. Very helpful!

When you say "your first coat at 50:50", are you saying mix water and primer 50:50?

karlitob

bystarlight wrote: »

Thanks very much for that. Very helpful!

When you say "your first coat at 50:50", are you saying mix water and primer 50:50?

Yes. Igoe on their website have a really good booklet with good advice. 50:50 is a very strong mix and perhaps not really needed. 1:2 or 1:3 (primer to paint) is perfectly suitable for masonry. I used 50:50 on concrete fence posts because they are so porous but a rendered is different I would think. Owatrol is relatively expansive. 1 L in a 5L bucket of paint is better than none at all. (Though it wouldn’t fit in the same bucket of course)

Hope it helps but perhaps someone who actually knows what they’re talking about might also post a response. Best of luck.

blueskys

Ya you are right mate its a case of water on oil...do as he says you'll be fine

romaderwdcsax

blueskys wrote: »

Ya you are right mate its a case of water on oil...do as he says you'll be fine

Absolutely 100% not the problem, water based paint is designed to go on over an oil based stabilising solution.
When u washed the wall with the bleach/water mix did you wash that off again with clean water? It could be a simple case of the paint reaction with the diluted bleach.
Best solution, use a power washer to completely remove every last bit of paint, let the wall fully dry out for a few days, then paint following the manufactures recommendations on the back of the paint container, add in a paint conditioner to the first coat.
Avoid using bleach where possible.

bystarlight

romaderwdcsax wrote: »

Absolutely 100% not the problem, water based paint is designed to go on over an oil based stabilising solution.
When u washed the wall with the bleach/water mix did you wash that off again with clean water? It could be a simple case of the paint reaction with the diluted bleach.
Best solution, use a power washer to completely remove every last bit of paint, let the wall fully dry out for a few days, then paint following the manufactures recommendations on the back of the paint container, add in a paint conditioner to the first coat.
Avoid using bleach where possible.

As far as I remember I did, yes. But maybe I didn't get it all off.

Taking off all the paint will be a big job, but if it has to be done it has to be done.

karlitob

romaderwdcsax wrote: »

Absolutely 100% not the problem, water based paint is designed to go on over an oil based stabilising solution.
When u washed the wall with the bleach/water mix did you wash that off again with clean water? It could be a simple case of the paint reaction with the diluted bleach.
Best solution, use a power washer to completely remove every last bit of paint, let the wall fully dry out for a few days, then paint following the manufactures recommendations on the back of the paint container, add in a paint conditioner to the first coat.
Avoid using bleach where possible.

I never said it wasn’t made to be used together. I used dulux oil based stabiliser on my house and water based colour trend over it. The point I made was about curing time.

Happy to defer to your expertise.

upupup

The weak spot on your wall is at the top where the brick sits on the wall.The normal wall cap has a drip which keeps a lot of rain away from the weak spot but your structure allows the rain to seep down around and through the brick.It can then easily get between the paint and the wall.
Seal that spot and maybe the brick for a fully waterproof job

A Law

bystarlight wrote: »

As far as I remember I did, yes. But maybe I didn't get it all off.

Taking off all the paint will be a big job, but if it has to be done it has to be done.

I took all the paint off my house last year. Base model nilfisk with the tornado nozzle. Slow work but takes it off with relative ease. Only problem is the paint everywhere, easier to sweep up when it dries out.