Treating Old External Wall before Painting

Scribbler100 · 23-08-2017 01:09PM #1

Am hoping for advice on painting an external wall. It is the outside of an extension which was probably built in the 70's. Areas of the wall had patches of bubbles and flakiness so I tried scrubbing, then scraping. Some areas are very difficult to shift and there appears to be some kind of green mould underneath some of the old paint.

I attach a photo and would like to know what I should do to remove all the problem paint and then prepare the area for a fresh coat of Weathershield. Any advice would be much appreciated.

dok_golf · 23-08-2017 09:16PM

Can't open that link ( fault at my end I think ) but you need to hit the wall with a good pressure washer ( even a home-use washer like a Karcher if it has the "dirt buster" attachment. ). Treat the wall before pressure washing with a decent fungicide ( Fleetwood do a good one as does sandtex). Power wash the wall. Hit it a 2nd time with the fungicide. then add a product called "Owatrol E-B" to your paint.It is recommended to use a mix of 3 parts paint to 1 part E-B ON THE FIRST COAT ONLY. I generally just throw in a mix of about 10:1. This will make any water based paint stick to irtually anything. Its a bit expensive but well worth it imo.

mad m · 23-08-2017 10:39PM

I'd be putting a stabilising solution paint on after you do all the donkey work before you put any type of exterior emulsion on it.

dok_golf · 24-08-2017 06:01AM

the E-B is a stabiliser

Scribbler100 · 24-08-2017 09:26AM

Thanks so much for the replies. Have spent the last two weeks painting the pebbledash house and thought the extension would be the easy bit :rolleyes:

Will go about sourcing a pressure washer, fungicide and the Owatral E-B. I'd imagine this job will take a good while longer than anticipated. Probably have to leave it a couple of days to dry between each stage? Firstly applying fungicide, then power washing, re-painting with fungicide, then finish with paint/stabiliser mix then final coat of paint.

I know it will be worth it though, rather than having the paint begin to lift away after a short while. Thanks again, I wouldn't have know where to start tackling this.

dok_golf · 25-08-2017 06:04AM

48hrs after first fungicide. power wash and 2 nd fungicide can be done on the one day ( just let walls dry after power wash). Then, following day, paint.

Scribbler100 · 25-08-2017 08:32AM

Thanks a million, dok_golf.

skydish79 · 01-02-2022 03:00PM

https://www.boards.ie/discussion/comment/104483278#Comment_104483278

Hi just wondering how did the walls turn out?

Which fungicidal treatment did you use

Scribbler100 · 01-02-2022 04:50PM

Turned out really well, still looking respectable. I think I used the Fleetwood fungicide.

Treating Old External Wall before Painting

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