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Exterior painting: the prep is the whole job

Two houses painted the same week with the same paint can look different in five years, and the difference is what happened before the first coat. What good prep is, and how to read a painting estimate.

By HomeMaxx · April 15, 2026 · 2 min read

Paint is not a coating that fails. It is a coating whose bond to the surface fails, and the bond is made or lost before the can is opened. Painters know this, which is why the estimates for the same house can be so far apart: one crew is quoting a day of prep and one is quoting a week.

What good prep includes

  • Washing. Pressure washing or hand scrubbing to remove dirt, chalk and mildew, then a full drying, at least a day or two. Paint over chalk peels in sheets.
  • Scraping and sanding every loose or peeling area back to a sound edge, then feathering the edge so it does not show.
  • Replacing rotten wood, not filling it. Filler in rot is a patch over a problem that is still growing.
  • Priming bare wood, every bit of it, with a primer suited to the wood and the topcoat. Tannin-rich woods such as cedar and redwood need a stain-blocking primer or they bleed through.
  • Caulking every joint that moves: trim to siding, around windows and doors. With a quality elastomeric caulk, not the cheapest tube in the aisle.
  • Setting the nails and filling the holes, and reglazing windows where the putty has failed.

On a house with lead paint, which is any house built before 1978, the crew must be certified under the federal rule for lead-safe work and must contain and clean up the dust. Ask to see the certificate. It is not optional and the fines are large.

The paint

A premium 100 percent acrylic exterior paint from a major maker costs more per gallon and lasts years longer; on a job where labor is most of the cost, the paint is not where to save. Two coats, always, unless the estimate says one and you know why. Sheen: flat hides flaws and shows dirt, satin is the usual compromise on siding, semi-gloss on trim and doors.

Weather

Paint needs the surface dry and the temperature in the range on the can, usually above 50 degrees for the day and the night after, and no rain for a day. A crew that paints in the wrong weather is hoping. Spring and fall are the seasons in most of the country; in the hot South, morning work in the shade.

Reading the estimate

A good painting estimate says, in words, what will be washed, scraped, replaced, primed and caulked; names the primer and the paint by brand and line; states the number of coats; and covers the lead-safe work if it applies. A price per square foot with none of that is a price for a day of prep, however it turns out. Ask how long the crew will be on site; a full prep on an average house takes as long as the painting.

What it should last

Good prep and good paint on sound wood: eight to ten years, longer in mild climates. Trim and the south and west walls go first. Touch up the failing areas when they start rather than waiting for the whole house, and the next full job is further off.

Trades this touches: Painting, Siding & Windows.

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