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Stains Appeared on Fresh Exterior Paint Work

Postby tomtom1983 » Tue Aug 22, 2017 2:33 pm


Hi all!

I'm hoping you can help!

Outside our house is a small wall and a few years ago I have it a fresh bit of paint!
No problems-all went well.

2 years later I thought I'd best do it again however after this I noticed that it started to stain and then eventually crack.
Not wanting to start a huge job I just went over it again and thought nothing of it.

Again the same thing happened! (Doh!)

So knowing it was a bigger job than just a lick of paint I left it.

This year (about 3 weeks ago) I stripped the wall right back to the brick/sandstone/cement top. Scrubbed it and even did a few repairs to make it a bit smoother!

Then I primed it and eventually painted it with new and better paint.

However....the stains have started to appear again!! Anyone know what it is and how to rectify it? I assume I'll have to take it back to the brick again which I don't really mind if it solves the problem! But obviously would prefer not too!

Have attached a pic of the stains however more pictures can be added if it helps!!

Hope that makes sense!!
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Postby Kneesworth » Wed Aug 30, 2017 12:45 pm

I'm presuming that you used a water based paint. The most likely cause of the staining is a greasy or other non water soluble deposit on the surface you painted. You can spray over the staining with a Stainblock (Get in most D.I.Y. shops) or paint over the stains with any oil/solvent based paint, then repaint with the water based.
Hope this solves it,
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Postby tomtom1983 » Wed Aug 30, 2017 6:35 pm

Hi Kneesworth,

Many thanks for your reply!
That's exactly what I have done, I've gone over the water based paint and stains with an oil based paint!
Once the sun comes back again (and it hasn't rained for a few days) I'll give it a brief sanding down and go over it with the water based paint once again! Minimum 2 coats!!
Hopefully that should work. The oil based coat has been on a good few days so far and can't see anything trying to get through yet! Watch this space! Shall let you know!
Thanks again for your response!
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