Interior Painting throughout Somerville, MA.

The Census Bureau puts the median year built for Somerville housing at 1938, a full generation older than the statewide median of 1964. Of the city's roughly 37,700 housing units, 59.0% were built in 1939 or earlier, close to double the Massachusetts share of 30.5%. Only 9.6% date from 2010 or later.

Those numbers shape the inside of a paint job more than the outside. A room in a house of that age may have original plaster walls, layers of paint going back decades, and door and window casings that have been coated many times over. The work is mostly preparation: finding what has failed, fixing it, and making sure the old paint underneath is handled safely.

Plaster walls and ceilings

Houses built before drywall became the usual wall finish were commonly plastered over wood lath. Plaster that has stayed attached is a hard, durable surface that paints well. The trouble spots are hairline cracks that open and close with the seasons, sections that have pulled away from the lath and feel spongy when pressed, and ceilings where an upstairs leak once left a stain or a bulge.

Each of those needs a different fix. Fine cracks can be opened slightly, taped and filled. Loose plaster may need to be reattached with plaster washers or cut out and patched before any primer goes on. Water stains need a stain-blocking primer, or the brown ring bleeds back through the new ceiling paint within days. A written estimate should name which repairs it includes so you can compare bids on equal terms.

• Crack repair and patching of loose or missing plaster
• Stain-blocking primer on old water marks
• Flat finishes on ceilings to hide surface waves
• Wall, trim, door and window casing repaints

Lead paint and dust control

The census groups construction by decade, and 79.8% of Somerville units fall in decades before 1980. That slightly overstates the share built before 1978, the year lead-based residential paint was banned, but the point stands: in most of the city's housing stock, old layers of paint should be assumed to contain lead until tested.

Under the federal Renovation, Repair and Painting rule, a firm that disturbs paint in a pre-1978 home must be certified and must use certified renovators. Inside a house, that means containment with plastic sheeting, no open-flame removal or power sanding without a HEPA shroud, HEPA cleanup and a final cleaning check. Window sashes and stair treads deserve the closest attention because friction grinds old paint into dust. The lead-safe painting page covers the Massachusetts rules, including what applies when a young child lives in the home.

The city has announced a $2.1 million HUD continuation grant for free de-leading of 120 Somerville units; that announcement, now in the city's news archive and undated, notes that de-leading frequently includes new windows and doors. Owners planning a full repaint may want to ask the city whether a de-leading program is currently open, since replacement windows change the trim scope.

Two-families, triple units and tenants

Somerville is a city of shared houses. Buildings with two units hold 28.2% of its housing, and buildings with three or four units hold another 27.0%. Renters occupy 65.8% of occupied homes. For an owner who lives on one floor and rents the other, interior painting often splits into two separate jobs: your own unit on your schedule, and the rental unit timed for a turnover, when rooms are empty and paint can cure without furniture pushed against it.

A rental repaint is a good time to pick one wall color and one trim color for every room, so that later touch-ups between tenants use a single can of each.

Permits and timing

Somerville's Building Division says a building permit is needed for interior and exterior work except painting, tiling and flooring, so a repaint on its own does not need one. Historic district review is limited to changes visible from a public way, which leaves interior color choices to you even in a Local Historic District.

Interior work can go ahead in any season. Winter painting is practical as long as rooms can be ventilated briefly; the winter interior painting guide explains what changes when windows stay shut. For outside work on the same house, see exterior painting in Somerville, and for kitchens, cabinet painting in Somerville.