Decks we build in Cambridge
Cambridge is almost its own category of deck building. Lot sizes are small, access is tight, and a large fraction of the housing stock is pre-1900. We're often working on triple-deckers in Mid Cambridge, Mansard-roof singles near Porter Square, or newer condo buildings in East Cambridge where the deck is on a flat roof. The design conversation is different here than in a suburb with a quarter-acre lot — square footage is precious, and the deck has to work hard.
Second- and third-story decks over small yards are our most common Cambridge build. They demand careful attention to the ledger — on a 120-year-old triple-decker, the rim joist can be old balloon-frame lumber that doesn't take a standard LedgerLok pattern. We open the siding, check what's actually there, and sometimes sister the rim before we hang the ledger. That extra day of work prevents a decade of water damage.
Roof decks are another Cambridge specialty — flat-roof condos in East Cambridge, Kendall-adjacent buildings, and some Harvard Square multi-families. Those require a different structural approach: pedestal systems, waterproof membrane protection, and attention to the roof's load capacity. We only build roof decks when the structural math works and the roofing membrane is sound; otherwise we tell you honestly.
Permits, inspections, and historic review in Cambridge
Cambridge deck permits are issued by the Inspectional Services Department at 831 Massachusetts Avenue. The permit application process is thorough and the department is busy — plan on three to four weeks from submission to issued permit for a straightforward build, and longer if historic review is triggered. That's just the Cambridge reality.
Historic review is where Cambridge differs most from the suburbs. The Cambridge Historical Commission oversees four local historic districts (Harvard Square, Old Cambridge, Mid Cambridge, and Avon Hill) and nine Neighborhood Conservation Districts covering most of the rest of the city. If your home falls in one of these — and most do — any exterior alteration visible from a public way requires Commission or NCD review before the building permit is issued.
For deck projects, the review typically focuses on railing style, decking material, visibility from the street, and whether the deck respects the architectural character of the house. We've been through this process and know what gets approved quickly and what gets sent back for revisions. We can tell you at the site walk whether your plan will clear review.
Inspections run the standard three stages: footings (if you have them — many Cambridge roof decks don't), framing, and final. Scheduling is through ISD's online portal.
What makes a Cambridge deck different
Material access and staging are harder in Cambridge than anywhere else we work. There is often no driveway. We pre-stage lumber in short deliveries, pay for Cambridge DPW street permits for occupancy during framing days, and schedule tight work windows so neighbors aren't losing their parking spot for a week.
Design-wise, Cambridge clients tend to care about two things: good proportions and material honesty. We see a lot of cedar and PVC (Azek) in Cambridge builds, and railing systems in cable or horizontal steel bar on the newer condo projects. On historic homes, the right answer is almost always a traditional wood railing in a profile that matches the house trim.
Materials we use on Cambridge decks
Material selection is one of the biggest decisions on any deck project. The three main options we build with in Cambridge:
- Pressure-treated pine. The most affordable path to a full deck — typically $30–45 per square foot installed. Needs stain or seal every 1–2 years to prevent gray-out. Properly maintained PT lasts 15–20 years. Good for budget-conscious builds or utility decks.
- Composite decking (TimberTech, Trex, Fiberon). $50–75 per square foot installed. Essentially maintenance-free — no staining, no sealing, no sanding. Resists rot, insects, and UV fade. 25-year warranties standard.
- Cedar or PVC (Azek). Cedar for a natural wood look with better rot resistance than PT. PVC for a wood-grain product that never rots and stays cool underfoot. $65–90 per square foot installed. The finish quality is noticeably better on both.
Underneath all three, we frame with kiln-dried pressure-treated southern yellow pine and galvanized or stainless hardware. Hardware upgrade to stainless is standard practice on any Cambridge deck within a few hundred yards of saltwater or in a damp microclimate.
How we actually build it, start to finish
Every project starts with a site walk, not a phone quote. We measure the house wall, check for existing footings, assess grade, decide where the ledger ties in, and talk through what you actually want the deck to do. From there:
- Design and material selection. We put together a plan showing dimensions, framing, railing style, and material. You sign off before we spend time on permits.
- Permit submission. We prepare the plot plan, framing diagram, and material spec, and file at the Cambridge building department.
- Footings. Below Massachusetts frost line (48 inches minimum), with a footing inspection before pour.
- Framing. Ledger with proper flashing, beams, joists, blocking. Framing inspection before decking goes down.
- Decking, railings, stairs. Boards installed with concealed fasteners (composite) or face-screwed (PT), stair stringers cut, railings assembled and secured.
- Final inspection and walk-through. You and the inspector both sign off.
A standard 16×14 deck with no complications runs seven to ten working days from ledger to final board, plus permit lead time at the front.
Recent projects
