Naked Science Forum
General Science => General Science => Topic started by: tamsinbell on 05/10/2018 09:56:58
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Salthiel asks:
"I have got a paint that is peeling off the walls of my house from the ground to the level of the foundation. The peeling starts with cracks in some places. How can I stop this?"
What do you think? Post below...
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Paint can peel off a surface due to either poor preparation prior to painting or moisture coming in from behind.
To prepare properly you need to clean off all the old paint, rub down with a fine abrasive to provide a good key, and clean off any grease eg wipe down with sugar soap, rinse, make sure surface is dry before painting with a primer . If you think the problem might be moisture from the wall you will need to use a moisture proof, bonding primer and any diy store will advise you on a good one.
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Paint peels because it isn't sticking to the substrate.
Most commonly, when wood is close to the ground, it takes in moisture and swells a bit, causing inelastic paint layer to crack.
A couple of fixes: paint the board on all 6 sides, preferably using acrylic paint (not latex) before installing it. Place a metal flashing under the board to prevent moisture from splashing up from the ground during rain. Alternatively, don't use wood here. consider a PVC trim board or fiber-cement.
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There are many reason why paint failure can occur, but moisture is a common cause of peeling or blistering paint on both interior and exterior walls. ... Moisture as a source of paint failure falls into three general categories: systemic moisture, structurally caused moisture, and moisture caused by human error.
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Paint peels because it bonds more strongly to itself than it does to the substrate.