Old houses can leave us with all kinds of peeling paint, so what do we do when we want to fix it up? Some people think you can just paint right over old paint without any issue, but this is not the case. Before starting, make sure you remove as much paint as feasibly possible by sanding or scraping the area. It’s so important to remove the existing coatings or substrate if you don’t want to play catch up later from painting straight over it.
To make sure the adhesion is adequate, test the coating surrounding any areas peeling about 6-12 inches out. If you leave behind any old coating, it will shorten the length of your new paint job for sure. Then, you will prime the bare surface with the appropriate primer and caulk where necessary (like in crevices and angles) to eliminate opportunities for moisture to penetrate into the substrate.
Keep in mind, when you remove old paint this will generate dust or fumes that contain lead. Exposure to this may cause brain damage or other adverse health effects, so be sure to wear protective equipment to keep yourself safe. You can wear a properly fitted respirator (NIOSH approved) and be sure to contain the dust and fumes, as well as clean them up well.
Next, you want to clean and repair gutters so they properly channel water away from the house. Install fans, louvers, vents, and dehumidifiers to relieve moisture, particularly in the kitchen, laundry room, and bathroom. Siding wedges can be installed to allow the moisture to escape between, instead of through, the boards.
Also, if any wood siding is touching the ground, or within 6 inches of it, remove that portion. You can replace deteriorated wood with redwood, cedar, or pressure-treated wood.
To reduce further moisture penetration, prime the butt ends of the wood before installation. Follow label and data page directions for environmental conditions and proper surface preparation. Just make sure the surface is dry prior to painting.
Always remember, the coatings you apply on top of the old wood are only as good as the existing substrate. The new paint will peel eventually when placed over old paint.