What went wrong - Outdoor painting? PICS Shown!

Movie Maestro

So I painted my newly plastered garden walls using Johnstons Masonary paint in September 2015 - did 2 coats. All was fine until last week when we got the blast of arctic weather. I woke up to find the paint is bubbling and literally falling off the wall. I has also painted the non-plastered part of the wall and that is fine.

Did I do something wrong in the first place? I've been told I should have maybe used a primer first. Someone else mentioned that large levels of lime in the plaster work might have caused this?

Can anyone advise me what my options are now please?

You can see in this first pic that the non-plastered paintwork is fine.

irelandspurs

salt in the plaster, its called efflorescence

Movie Maestro

irelandspurs wrote: »

salt in the plaster, its called efflorescence

Thanks for the info irelandspurs. I'm just looking for some advice on how to proceed with this now

flutered

you needed to prime the walls befor painting them, scrape off as much of the old paint as possible, get some concrete sealer from you hardware or paint supplier, seal and re paint

Movie Maestro

flutered wrote: »

you needed to prime the walls befor painting them, scrape off as much of the old paint as possible, get some concrete sealer from you hardware or paint supplier, seal and re paint

Cheers flutered, appreciate the advice. That was probably my main mistake alright - not priming the walls beforehand

dpofloinn

Just to add johnstones masonry paint is absolute dog muck I've had this issue more than once with that brand

irelandspurs

dpofloinn wrote: »

Just to add johnstones masonry paint is absolute dog muck I've had this issue more than once with that brand

Its one of the better ones. No waterbased masonry will hold back efflorescence. You'll need alkali resisting primer on the effected areas and allowed to drive.

Czhornet

If the wall has been plastered for a few years and has got weather beaten then the fine sand/cement finish will have been eroded leaving the "larger" aggregate in the plaster exposed which paint does not stick to.

You will have to scrape or power wash off all the old paint and put on oil based primer called Pliolite. most paint shops will have it or some form of it.

I used this when painting my house for the first time with 7 years exposed plaster.

http://www.thepaintshed.com/products/macpherson/powerkote-pliolite-masonry-/c-24/c-202

dodzy

OP, you need this.

http://www.leylandtrade.com/products/product-detail/truguard-stabilising-masonry-primer.aspx

As said scrape off any loose paint. Don't break your heart - just the loose flaky stuff. Apply a coat or 2 of this stuff. Next day, reapply the topcoat. And you're done.

Movie Maestro

Cheers for all the advice folks! Looks like scraping off the flaky stuff and applying masonary primer is the way to go, before repainting.