Exterior Painting in Milford, MA.

An exterior repaint is mostly preparation. Scraping, washing, repairs and primer decide whether the finish coats last, and the right steps depend on what the house is clad in and how old its paint layers are. Local housing runs from colonial-era survivors to recent construction: the National Register lists the Georgian-style Azariah Newton House on Silver Hill Road, whose Park Service record gives 1747 as its significant year, while 12.9% of today's housing units were built in 2000 or later.

Between those extremes sits the bulk of the stock. Census estimates show 63.8% of units built before 1980, which brings lead paint into play on the outside of many houses.

Asbestos-cement shingle: paint it, don't sand it

Some older siding here is not wood at all. The 1990 National Register nomination for the Prospect Heights Historic District records that in the early 1950s the Draper Corporation covered all of its wood-framed company houses with asbestos shingle to cut repair and painting costs, and that later owners painted it, mostly white, gray, green or brown. If a house elsewhere in town has a hard, brittle shingle that looks similar, treat it with the same caution until a test says otherwise.

Intact asbestos-cement shingle is often repainted rather than removed, but the prep is different from wood. EPA guidance for homeowners is to leave asbestos-containing material alone when it is in good condition and not to saw, sand, scrape or drill it. That rules out aggressive scraping and power sanding; cleaning is done gently, loose paint is handled with care, and cracked or broken shingles are flagged for a specialist rather than patched in place.

Wood clapboard, trim and porches on older houses

Over a fifth of local housing units, 22.6%, date from 1939 or earlier. On wood siding of that age, paint failure tends to start where water lingers: window sills, the bottom edges of clapboards, porch floors and the end grain of corner boards. Bare wood gets an oil-based or bonding primer, open joints get caulked, and rotted sections are replaced before any coating goes on.

Paint applied before 1978 may contain lead. The EPA's lead rule kicks in when paid work disturbs more than 20 square feet of paint on the outside of a pre-1978 home, an area about four feet by five, so a repaint that involves real scraping can pass it quickly. That means ground covering, containment, misting or hand scraping instead of dry power tools, and careful cleanup of chips around foundations and gardens. Details are on our lead-safe painting page.

Brick and decorative trim in the Draper rowhouses

The Prospect Heights nomination also describes red-brick multifamily rowhouses with granite window sills, stone foundations and a blue-and-yellow cast-brick diamond logo in the gables, plus bargeboard and stick trim in gables, dormers and door hoods. It said many of the brick buildings needed repainting, yet it recorded only two smaller units, at 1-2 and 41-42 Prospect Heights, whose brick itself had been painted. On those, or on any brick already under paint, use a breathable masonry coating and keep pressure washing gentle enough to spare the mortar; unpainted brick and the logo diamonds are better left bare.

The district is on the National Register; we did not find a local historic district bylaw for the town, but check with town hall before changing materials or colors on a listed building. The Prospect Heights page has more on the neighborhood.

When exterior work can happen

Paint needs surface and air temperatures inside the label range, dry siding and enough daylight for each coat to set before evening dew. Around here the practical window is late spring through early fall, with some shoulder weeks when products rated for lower temperatures are used. Our article on painting an exterior in November explains where the cutoff falls. For signs your siding is due, see when to repaint a New England house.