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When it rains the paint bubbles. When I clean the surface should I seal or waterproof the surface before painting. If so which product
thanks
Welcome to the Bunnings Workshop community Rosco64. We're pleased to have you join us and trust you'll get loads of inspiration and advice for all your projects around the house and garden.
Do you know if this is a brick retaining wall that has been rendered? I suspect you have the problem described by one of our resident Bunnings D.I.Y. experts Mitch in this Best Advice article: How do you paint a brick retaining wall?
"Brick retaining walls that have soil buildup on the other side of them are notorious for blowing the paint off through hydrostatic pressure. The water in the soil tries to migrate through the wall, and your paint seals the outside of the wall. This pressure causes the paint to delaminate and flake off.
To ensure you give the paint the best chance, I'd recommend first painting the wall with Crommelin's Aquablock. You can then proceed with using a quality exterior paint like Dulux Weathershield.
Unfortunately, depending on the amount of water that gets retained behind the wall, there's always a chance that your painted coating will fail. If it does, you might like to explore other decorative options like screening or cladding the wall with fibre-cement sheeting."
Hope that helps. Please don't hesitate to post anytime you need a hand.
Jason
Hi @Rosco64
Your raised garden is acting like a giant swimming pool and water is trying to find a way out of it. Ideally a series of PVC pipes should have been laid at the bottom of the garden and an outlet would have been placed at the side of the garden wall. This would facilitate drainage and prevent water build up inside the garden walls. Failure to drain the excess water will result in flooding or in this case water will find the nearest exit.
It's important to address the excess water buildup inside the garden as any painting solution will face the issue of hydrostatic pressure. Water passes through the concrete block and pushes on the layer of paint on top. It is a bit concerning when you see bubbles and water droplets forming on the surface of the wall. This means that there is a great deal of water that is forming behind the wall.
I propose thinking about drilling a hole on the side of your raised concrete garden to allow the excess water buildup to drain away. I also suggest having a look at Dunlop 4L Damp-Proof Waterproofing. it's an acrylic brush-on membrane, and will prevent rising damp, efflorescence. It will also resist negative hydrostatic pressure. However, intense pressure from the other side of the wall will eventually break the seal.
If you need further assistance, please let me know.
Eric
