Roofing in Watertown, Massachusetts

Why do Watertown triple-deckers have roofs that are partly flat?

The triple-decker was a tall, narrow house on a small lot, designed to hold three households. An estimated 15,000 were built in Boston and nearby cities between 1880 and 1930, and Watertown is among the places where they stand. Some have pitched roofs. Others have flat or low-slope sections, especially over rear porches, bays and additions, and in some places the whole roof is nearly flat.

A flat roof drains slowly, so water stays on the surface longer than it does on a pitched roof. That puts weight on every seam, every drain and every edge where the membrane turns up a wall. Roofs like this fail at details, not across the field.

The flat roof and EPDM page explains how a membrane is repaired or replaced. For the whole picture, read the guide to flat roofs on triple-deckers, which includes the published cost figures and notes where the guides disagree.

What gets checked on a roof that is half pitched and half flat?

A roofer starts with the line where the two meet. A sloped roof running down onto a flat one sends a lot of water to one spot, and the flashing there has to cope. Next come the drains and scuppers on the flat section, since a blocked one holds water against the membrane.

Wall flashing comes after that. Where the flat membrane meets a brick or wood wall, it should turn up and be covered by counter-flashing. If it has pulled away, water runs behind it and into the wall, which is why a stain on a second-floor ceiling can be much lower than the actual leak.

Pitched sections on older Watertown houses commonly use asphalt shingles. A roofer who is asked to repair only one section should say whether the other is close behind, so you can plan the work instead of paying for two separate visits. The multi-family roofing page covers shared roofs and the decisions that go with them.

Ask for photos of the flat section before and after the work. A roof deck that is hard to see from the ground is easy to describe in words and hard to check. A roofer who documents seams, drains and wall edges gives you something to compare against a second quote.

Who has to agree to a roof job on a two-family house?

That depends on ownership. If one person owns the whole building, the decision is theirs, though tenants need notice before a crew arrives. If the units are condos, the condo documents and the association usually govern, and a vote may be needed for a roof that serves everyone.

The permit is a separate matter. Watertown is a different city from Newton, so a roof replacement here is handled by Watertown's own building department, and we have not sourced its rules or fees. Ask the roofer who will apply, and ask the department what it requires.

Massachusetts issues no roofing licence. Contractors doing work on homes register as Home Improvement Contractors with the Office of Consumer Affairs and Business Regulation, and the building permit for roof work is normally pulled by the holder of a Construction Supervisor Licence issued by the Board of Building Regulations and Standards. The registration guide explains the terms.