Here’s the last in our instalments of mistakes to avoid when painting the outside of your house. For a job that lasts, don’t try this at home.
Waiting too long between the primer coat and the finish coat
After applying an oil-based primer, you should apply your next coat within two weeks. Otherwise, a layer forms on top of the primer and stops good adhesion, leading to quick peeling.
Using too much or too little paint
If you spread the paint too thinly, you won’t adequately cover the layer underneath, which at best looks bad, and at worst, can lead to problems. But when you apply the paint too thickly, you can increase the chance of heat blistering and cracking.
Don’t repaint areas that don’t need it, such as sheltered areas under porch roofs and soffits. These can probably be painted every second time you paint. And follow the manufacturer’s instructions when applying paint. Start with a good amount of paint on the brush and spread it evenly to either side of the first stroke. A full coat (primer and two top coats) should end up being about 5 milimeters thick — or about the thickness of a garbage bag.
Using the wrong paint on porous surfaces
Concrete and brick can soak up moisture and release it. If you paint these materials with oil-based paint, you can end up trapping the moisture inside, which leads to peeling as the sun tries to draw out the vapor. Latex paint allows the moisture to come through the paint without damaging the surface.