Condo Painting across Northbridge, Massachusetts.

Shared-wall housing is a solid slice of the local mix. Census estimates count 953 single-family attached units, the townhouse form, plus 1,213 units in two- to four-unit buildings and 960 in buildings of five or more, including 206 in buildings of fifty or more. The Census does not say which of these are condominiums and which are rentals, but together they show how many homes share a roof, a stairwell or a siding job with neighbors.

Shared walls have deep roots here. The Whitin mills built workers' duplexes, row houses and multi-family tenements, and the Rockdale Common Housing District preserves six of those tenements, four of them triple-deckers. Where an older two-family or multi-family building is held as condominiums today, it carries the paint history of its era.

Inside your own unit

The master deed and the association's rules decide what belongs to you and what belongs to everyone. Interior walls, ceilings, doors and trim may well be on your side of that line, but read your documents before hiring anyone, and check for rules on working hours, parking for a contractor's van, protecting shared floors, and notice to the property manager.

A unit repaint is often a straightforward interior job: patching, priming repairs, and fresh coats on walls and trim. The interior painting page covers surfaces and prep in more detail, and the cabinet painting page handles kitchens and vanities.

• Neutral repaints before listing a unit for sale
• Turnover painting between tenants
• Ceiling stain repair after a leak from the unit above, once it is fixed
• Trim, doors and closets alongside walls

Rentals and lead rules

Renters occupy 29.5% of occupied housing in town, and if you lease out your unit, the rules on old paint matter to you and your tenant alike. Any paid work disturbing paint in a pre-1978 unit falls under the EPA's renovation rule once it passes six square feet per room inside or 20 square feet outside. With 55.9% of local housing built before 1980, owners of older units should plan for lead-safe methods on window and door repairs. Our lead-safe painting page explains what that work involves.

Halls, stairwells and exteriors for the board

Corridors, lobbies, stair towers, entry doors and the building exterior are the board's to decide, and paid from association funds, wherever the master deed lists them as common elements. Because residents keep using these spaces during the work, a sound plan covers painting in sections, posted notices before each area starts, a clear walking path, and low-odor products in enclosed halls.

Exterior jobs on a multi-unit building add height and coordination: staging around shared entries, moving parked cars, and planning around balconies and decks that owners use. The exterior painting page describes surface prep for clapboard and siding.

Insurance and paperwork

A board or manager may ask for proof of insurance before a contractor sets foot in common areas, sometimes with the association named as certificate holder. AJ Painting is licensed and insured; ask for proof of coverage at the estimate if your association requires it. For damage inside units, the line between the association's master policy and an owner's own policy is set by your documents and your insurer.