Exterior Painting right here in Acton, Massachusetts.

An exterior paint job is mostly decided before the first coat: how much failing paint comes off, how wood repairs are handled, and whether anything about the house triggers town review. The review question is real here, because Acton has three local historic districts, West Acton, Acton Center and South Acton, created by a Special Town Meeting vote in 1990.

The good news for anyone who only wants new color: the Historic District Commission's annual letter to property owners lists paint color among the items that typically do not need a Certificate of Appropriateness. What the commission does review is exterior change visible from the public way, such as windows, trim, vents, porches and gutters.

When a paint job turns into a district review

Scraping can uncover rot. If the work grows into replacing a porch rail, swapping out window trim or changing a profile, it moves into the commission's territory. A building permit will not be issued for exterior work in a district without either a Certificate of Appropriateness or a Certificate of Non-Applicability, the faster certificate the chair can approve for minor work such as in-kind repairs. Both are good for a year from issuance and can be renewed with the commission's approval.

The town says review can take up to 60 days, though most applications move faster, and every application requires notice to abutters. The commission meets on the second and fourth Tuesday of each month. Raising the question early, before scaffolding goes up, avoids a stalled job halfway through the season.

Older houses outside the districts

Historic houses are not limited to the three districts. Over 800 properties are on the town's Cultural Resource List and in the state MACRIS inventory. For those, the Building Department alerts the Historical Commission when a permit application would affect more than 25% of a facade or remove an element like a chimney, porch or bay window. Repainting alone does not match either trigger as the town describes them, but large-scale siding or porch replacement on a listed house can.

Acton Centre was listed on the National Register in 1983. Its houses are described as mostly Federal or Greek Revival, with some Italianate, Queen Anne and Colonial Revival examples. Houses in those styles can have cornices, corner boards, window heads and porch columns, and each of those pieces needs its own scraping, priming and caulking before paint.

Lead on siding and trim

Of the roughly 9,600 housing units in town, 60.7% were built before 1980, the closest Census bracket to the 1978 federal cutoff. On a pre-1978 exterior, the EPA's RRP Rule applies once paid work disturbs more than 20 square feet of paint, an area roughly 4 by 5 feet. That requires ground tarps, limits on open-flame and high-speed power removal, and cleanup of paint chips before the job ends.

See the lead-safe painting page for the step-by-step version. For a house from the 1960s or 70s, testing the original trim and siding settles whether those rules apply.

Prep, season and the paint itself

Exterior coatings need surface and air temperatures within the label range and dry weather while they cure, which in eastern Massachusetts usually means late spring through early fall. Painting an exterior in November explains the late-season limits, and common exterior paint failures shows what blistering and peeling are telling you. A deck or porch floor can be done in the same visit; the deck staining page covers that side.

• Wash siding and let it dry; paint does not bond to chalk or mildew
• Scrape and feather-sand failing areas, then spot-prime bare wood the same day it is exposed
• Replace or epoxy-repair soft wood at sills, drip caps and corner boards
• Caulk joints that move, but leave the gaps under clapboard laps open so the wall can drain