Preparation of the surface prior to painting your home is the most important step to ensure a lasting paint job. Paint failure rarely causes a paint job not to last, most of the time the guilty party is bad adhesion. There are three factors that cause paint to not adhere: dirt, moisture, and loose substrate (underlying layer). Before you start to apply the new coatings make sure the surface is clean of any dirt or oils, completely dry, and free of any loose paint so that the primer and new paint have a good surface from which to bond. Proper preparation is by far the most important key to long lasting paint job.
In order to paint your home you first must be able to access all areas that will be painted, right? That means you might need to do some landscaping and reorganization around the house before getting started.
- Trim or pull back any trees and plants that might be restricting you from reaching different parts of the house.
- Move vehicles away from the house. (Don’t want paint on the new car)
- Turn off the A/C and cover it with a drop cloth or plastic.
Next, take down anything you can from the house so there is less to mask.
- Remove light fixtures and decorations.
- Take off window screens and shutters.
- Shutters and other objects can be painted separately and reattached after the house is painted.
The next step in paint surface preparation is to remove the loose paint either by power washing or by hand scraping. For an experienced painter a power washer can remove loose paint very quickly, however in the hands of the inexperienced it can do damage your home. At high pressures the spray can splinter wood, etch brick and even blast mortar from joints. For the novice painter I suggest using a lower pressure to clean the surface and then hand scrape to prevent unwanted damage.
Even with power washing you may still have to scrape and sand to properly prepare the surface since loose paint is not always removed with a power washer. Here are some scraping tips:
- Make sure the paint is dry before scraping.
- Use a paint scraper, 5-in-1, or wire brush for the best results.
- Start with the loosest part of the peeling paint and work out from there.
- Be careful when scraping wood because paint scrapers can gouge leaving unsightly damage.
When the loose paint is scraped away, the next step is to sand the surfaces where paint has been removed. It is important to feather the hard edge transition where paint has been separated from the substrate to give it a more uniform surface for painting. Sanding is especially needed on smooth surfaces. Brick and stucco, on the other hand, are substrates that already have a textured surface so sanding usually is not needed.
- For large areas, use an orbital power sander.
- A sanding block with hand sanding works well in smaller areas.
- For best results use 80-120 grit sandpaper.
- Wipe down surface after sanding to clean off any dust.
Once the house has been washed, scraped and sanded it will need to be dry before painting can begin. This is very important to ensure that the new paint adheres properly to the prepped surfaces. Not letting the house dry before painting is a common cause of paint failure.
The last preparation steps you need to take before finally painting are repairs, sealants, and masking.
- Caulk gaps around windows/doors, fascia joints, masonry cracks, etc.
- Float smooth and retexture missing stucco, fill cracks using synthetic textured patching compound.
- Fill cracked wood with an elastomeric coating to smooth surface and prevent future cracking.
- Mask off or cover any surfaces that will not be getting paint: windows/doors, meters, brick, A/C, grill, etc.
Only after you have completed all of these steps will you be ready to paint with the confidence that the new paint will adhere correctly and your paint job last.