Triple-Decker and Multifamily Water Damage in Massachusetts

Speed matters in a triple-decker because the building is a stack of wood-frame flats, one per floor, with kitchens and baths usually lined up above each other. An estimated 15,000 to 16,000 of these buildings went up in Boston and the surrounding cities between 1880 and 1930, and across Massachusetts they still house many renters. Water from a failed washer hose on the third floor runs across the floor, finds the plumbing chase and comes down through the second-floor kitchen ceiling and then the first. Old plaster, layers of flooring and decades of patched walls hold that water and hide how far it went.

In the first hour, water spreads across the source floor and starts dripping into the unit below. By 24 hours it has soaked the subfloor, wicked into plaster and drywall and reached the first-floor ceiling. At 48 hours, wet wall cavities and floor layers are where mold can start, and swollen hardwood and subfloor begin to cup. After a week without drying, ceilings may need to come down in two units, tenants may need to move out for a while, and a one-unit leak has turned into a whole-building repair.

A lot of a triple-decker can be dried in place when the water is clean and the crew starts early. Plaster on wood lath is dense and slow to dry, but it often survives when air is pushed into the cavity behind it and the room is dehumidified. Hardwood floors on the source level can often be saved with mat systems that pull water up through the boards. Wall studs, floor joists and subfloor dry well once ceiling bays and wall cavities are opened at the bottom for airflow. Kitchen cabinets can usually stay if the toe kicks are pulled and air is forced underneath.

Some materials have to go. Drywall ceilings that sagged or collapsed come down, and so do ceiling sections where water pooled long enough to soften the board. Carpet pad that soaked through is replaced, and laminate or engineered flooring that swelled at the seams rarely lies flat again. Insulation in a wet ceiling bay holds water and is pulled. If the source was a toilet with waste in it or a drain line, the water is category 2 or 3, and porous materials it reached are removed in every affected unit.

Triple-deckers are common across older Massachusetts cities. In Boston, about 47 percent of homes were built before 1940 and only about 36 percent are owner-occupied, so many stacked flats in Dorchester, East Boston and Jamaica Plain are rentals with tenants on every floor. Somerville has the oldest stock of the large cities, with about 59 percent of homes built before 1940. Worcester, where the median home dates to 1951, has many triple-deckers, and winter leaks there follow nights like February 4, 2023, when the city hit 13 below zero.

Farther out, Lowell, Lawrence and Haverhill in the Merrimack Valley mix triple-deckers with converted mill apartments, and Lawrence is only about 28 percent owner-occupied. On the SouthCoast, New Bedford has a median build year of 1938 and Fall River of 1945, both rich in triple-decker housing. When an owner or landlord calls, the line asks which floor the water started on and how many units are wet, then connects the call with a local restoration crew that works that part of Massachusetts.