How Much Scraping and Sanding is Really Necessary?

Painting an exterior in the summer

Painting an exterior in the summer

As a morning runner I spend a lot of time looking at houses and exterior paint and there is a home on my route that has had ladders outside for the last year. The owner is an acquaintance whom I know through my kids’ sports. When he began the project a year ago he had mentioned in passing that he was painting the exterior. Well, it appears that he has been scraping paint for 6 of the last 12 months. It doesn’t look like the house has any rotted wood that needs to be replaced or any structural issues, but it makes me wonder – how much paint is he going to scrape? How much paint do you need to scrape before you can begin priming and painting?

I took the question to my local Hirshfield’s manager, Grant Richards, and he gave me the following guidelines for prepping (and scraping!) exteriors:

  • How much scraping is enough? As a standard rule of thumb, when there isn’t any more flaking you’re in good shape. Remember, your paint is going to bond to the surface and if that surface is loose and flaky, then the new paint has nothing to cling to. Be sure that the surface is clear of loose paint chips and debris to get the best adhesion.
  • Do I need to sand after scraping? If you’ve done a good job of scraping away loose chips, most people will not be able to detect the edges of pre-existing paint on the surfaces. Certainly, various wood has unique qualities, but overall, you should not need to sand your exterior prior to painting. Another alternative to endless scraping is a product Grant recommends called “Peel Bond” by XIM. It’s an adhesive that goes on clear and bridges over the edges and essentially glues down the edge of pre-existing paint.
  • Do I have to apply a primer? If so, what kind? In the old days, this was a given. However, there are a number of new paints out there that are actually self-priming. Try products like Hirshfield’s Platinum exterior or Benjamin Moore’s Aura exterior. Both are self-priming and with a couple of coats you’ll be in good shape.
  • How late in the year can I paint my exterior? Grant tells me painters work on exteriors into early November. That said, we’re talking about weather in the upper Midwest, so you need to consider two things: Temperature and dew point. If temperatures are in the upper 30’s or 40 degree range it’s possible to paint exteriors, but to be safe, check with local painting professionals for their advice.



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