How to build a roof deck in Boston

Ask the Expert Home Improvement New Construction
A roof deck in East Boston.
A roof deck Savatsky built in East Boston. Marc Savatsky

Do you dream of entertaining friends on your very own roof deck?

You aren’t alone, said Marc Savatsky, a builder/developer with Choose Boston and co-host of the podcast Real Estate Addicts.

“Roof decks are a major selling feature of any property,” Savatsky said, adding that it’s especially appealing to city dwellers who “have to find outdoor space creatively anywhere we can.”

Savatsky offered the following four tips for building a roof deck on your home.

Be patient

“It’s a very involved process,” Savatsky said. “It’s not quick.”

You’ll need patience, time, and money. The whole process, from designing the deck to getting permits to building it, usually takes five to six months, Savatsky said.

“If you do need to seek variances, that six months could easily approach up to 10 months,” he said.

You’ll want to budget appropriately, because a modest roof deck can begin at $30,000, and that’s not including hiring your architect and other professionals, Savatsky said.

Hire an architect

Before hiring the architect, you can have a preliminary conversation to see whether it’s even possible to add a roof deck to your property, Savatsky said. First off, the architect will want to know your address.

“The Boston zoning code varies neighborhood to neighborhood and sometimes even within a neighborhood,” he said.

Other questions the architect may ask: Is the roof deck for private use, or will it be shared with others in your building? How many stories is your building? Is there existing access to the roof?

Once you hire an architect — which typically costs between $7,000 and $10,000 — you’ll need to schedule an on-site visit so the professional can examine your building.

“If the building was not initially constructed to support a roof deck, you’ll likely need to add supplemental structural work,” he said.

In addition to the architectural drawings, your architect will engage a surveyor to produce a plot plan, which will be used to demonstrate that the required distances from the property lines are being followed. The price for the survey can range from $1,000 to $3,000, Savatsky said.

In addition to a surveyor, your architect will work with a licensed structural engineer, at a cost of around $3,000, he said.

Note: Let your architect and the structural engineer know how you want to use your deck. If you are planning a rooftop garden, then that will add to the weight load.

Submit the plans

Your team of professionals will submit your plans to the city’s Inspectional Services Department, which will typically answer you in 30 days, Savatsky said.

The city will either issue you a permit to build a roof deck or send you a refusal letter, which may note specific violations, he said. If your plans are approved, you can hire a contractor because it’s time to build.

If you received a refusal letter and want to continue with the project, you’ll need to hire a zoning attorney to help you address the variances needed with the Zoning Board of Appeal, he said.

Savatsky noted that if your property is either a one- or two-family house, then you are eligible to proceed through a streamlined Zoning Board of Appeal process, which means you will meet with a subcommittee of the board.

“From my experience, the subcommittee, there’s a little less formality to it,” he said.

Research materials

Once you get the green light to build, you’ll need to figure out what type of materials you want to use.

Pressure-treated wood is the least expensive, Savatsky said. Trex decking, or composite decking, costs a little more, he said. Exterior hardwood is the most expensive, he said. You’ll also need to pick the material for your railings: Do you want cable, iron, aluminum, wood?

When deciding, you should factor in the maintenance required, as well as the cost, he said.

“If you build composite decking and aluminum railings, there is very little maintenance,” he said. “Pressure-treated wood decking with painted wood railings would require the most upkeep because you’d have to power wash, sand, and paint every five to seven years.”

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