Custom accessory dwellings in Concord and Greater Boston Massachusetts

SCHEDULE A SIGHTLINE WALK
A cozy house in a suburban neighborhood during sunset with two people, a woman sitting on the front porch reading a book with a dog beside her, and a man walking with flowers. ADU. Accessory Dwelling Unit.

Your mindful partner in estate extensions, from concept to creation, for generational living.

A private, permanent home on the property you already have. Designed, permitted, and built by one team.

Various colored paints in small round containers, seashells, a dry fern leaf, a wooden plank, pieces of fabric, and a piece of natural fiber rug arranged on a surface. ADU. Accessory Dwelling Unit. Porchlight.
Architectural floor plan for a porchlight model with dimensions, including a living room, kitchen, bathroom, bedroom, mudroom, and porches. ADU. Accessory Dwelling Unit. Porchlight.

2004

BUILDING SINCE

Porchlight | Bespoke Accessory Living

70+ YEARS

OF BUILDING BETWEEN THREE PRINCIPALS

A porch light is not decoration. It sends one specific message: someone is expected, and this house is ready for them. You leave it on for a daughter driving back from school. You leave it on for a father who does not live here yet but might. It is the oldest signal a family has for "there is room."

A cozy ADU Accessory Dwelling Unit) house with a front porch in a suburban neighborhood, the sun setting behind trees, a woman gardening, and a man sitting on the porch reading. Porchlight.

Distance is not the same as independence.

Families are usually told the choice is move in or move away. There is a third answer, and it is forty feet from the back door.

A parent who should not be an hour away. An adult child who needs a footing. A property with more life in it than it currently holds. These are not housing problems. They are family questions, and they deserve more consideration than a structure delivered on a flatbed.

WHAT WE BUILD

An estate extension, not a unit in the yard.

An accessory dwelling is not a small project. It is a small house.

It needs a foundation, a roof that sheds properly, a heating system, a kitchen that works, and finish carpentry that will still look right in fifteen years. We build about twenty homes a year, and have since 2004. Most companies selling accessory dwellings have never built a house at all.

Yours is designed to the house already standing there: matched to its scale, its materials, and its lines, and sited so that two households share a property without sharing a window. From the driveway it should look like it was always meant to be there.

A suburban home with a green exterior, a driveway with a car, and a backyard patio where two people are sitting at a table. ADU. Accessory Dwelling Unit. Porchlight.

THE PROCESS

From concept to creation

01

The Sight Walk

We walk your property before anyone draws anything. Grade, access, utilities, trees, and above all sight lines. Most of the design gets decided standing outside. Nothing is sold on this visit.

02

The Drawings

Concept, siting, and architecture, designed to the house that is already there. Elevations, floor plans, and how it looks from your kitchen window.

03

The Paper

Zoning, permitting, abutters, septic, and utilities. Massachusetts allows accessory dwellings by right, and that is good news, but by right is not the same as automatic. We handle the town.

04

The Build

Sitework through finish carpentry, by the trades who have built for CoughlinShea for two decades.

05

The Light

Final walkthrough, warranty, and the first night someone stays in it.

MASSACHUSETTS, BY RIGHT

Massachusetts changed the rules. Here is what that means for your property.

Floor plan showing a garage with two cars, a mudroom, a staircase, bathroom, kitchen, living area, and a deck outside. ADU. Accessory Dwelling Unit. Porchlight.

Since February 2025, accessory dwellings under 900 square feet are allowed by right in single-family zoning districts across Massachusetts. No special permit. Your town cannot require you to live in either home, and if you are within half a mile of transit it cannot require additional parking.

What towns still control: setbacks, height, lot coverage, building and trade permits, and wetlands, historic, and health review. That is where projects still stall, and it is the part we take off your hands.

One thing worth knowing early: the by-right protection caps at 900 square feet, or half your main house, whichever is smaller. Above that line you are into discretionary approval. We will tell you which side of it your plans fall on during the Sightline Walk, before you are invested in a drawing.

900

NO

NONE

SQUARE FEET, BY RIGHT

OWNER-OCCUPANCY REQUIREMENT

ADDED PARKING
WITHIN A HALF MILE OF TRANSIT