Choosing a contractor for a home addition comes down to three things: proof they have built additions (not only kitchens or decks), the credentials and insurance your state requires, and a detailed written price and contract you can compare against other bids. An addition is new construction joined to an old house, so the contractor has to handle a foundation, framing, a roof tie-in, matching siding and windows, permits and zoning, and the rooms where the old and new meet. This guide covers what to check, what to ask and how to compare quotes.

Norman Builders is a design-build home builder founded in 2007 by Ryan Norman, with an office at 63 Peaslee Crossing in Newton, NH. We build home additions, including family rooms, second- and third-level additions, garage additions, in-law additions and sunrooms, across the Merrimack Valley, the North Shore, the Seacoast and southern New Hampshire.

Why the Contractor Matters More on an Addition

The Role of a Contractor in Home Additions

  • Project management: the contractor schedules the work, orders materials, pulls permits and books inspections.
  • Coordination: an addition brings in excavation, foundation, framing, roofing, siding, electrical, plumbing, HVAC, insulation, drywall and finish trades, all in sequence.
  • Quality control: the contractor is responsible for the workmanship of every trade, including the subcontractors.

What Is Different About Additions

  • Structure: a new foundation, or for a second story, an engineer's check that the existing house can carry another floor.
  • Tie-ins: the new roof, walls and floors have to meet the old ones without leaks, cracks or uneven floors.
  • Matching: rooflines, siding, trim and window proportions decide whether the addition looks original or tacked on.
  • Town rules: setbacks, height limits, lot coverage and, for added bedrooms, septic capacity. In Massachusetts, Title 5 sizes septic systems by bedroom count, and New Hampshire also sizes them by bedrooms.

Choosing the Right Contractor for Your Home Addition

Evaluating Contractor Credentials

  • Massachusetts: home improvement contractors must register in the state's Home Improvement Contractor (HIC) program, and the person supervising structural work such as an addition needs a Construction Supervisor License (CSL).
  • New Hampshire: there is no state license for general contractors, so references, insurance and a written contract carry more weight. Electricians and plumbers are licensed through the state.
  • Insurance: ask the contractor's insurer to send certificates of general liability and workers' compensation coverage.

Our guide to contractors license rules in MA and NH explains each credential and where to look it up.

Importance of Local Experience

A contractor who works in your area knows the building departments, the zoning boards, the soil and ledge you may hit when digging a foundation, and what New England weather does to a schedule. Debbie White of Hampstead, NH, whose project grew into an addition, wrote that "bad weather did delay new construction" but "all proceeded timely thereafter." Ask how a contractor plans around winter for foundation and roof work.

Past Projects

Ask to see additions specifically, ideally ones like yours, and look at how the new part meets the old: the roofline, the siding, the floor transitions inside. Our published additions are listed below and on our home addition projects page.

Where to Find Addition Contractors

  • Referrals: neighbors and friends who have added on. John H. of Newmarket, NH wrote that he was "introduced to Ryan Norman by friends" and "could see from their house that his work was top quality."
  • Review sites: Houzz, Angi and Google show reviews and project photos. Look for patterns across many reviews rather than one glowing or angry one. Linda B. of North Andover wrote that she was "Impressed by the Angie's List reviews raving about Norman Builders."
  • Interviews: talk to more than one contractor. Al and Linda C. of Bradford, who hired us for a deck and screen room rather than an addition, wrote that Norman Builders "was our top choice among three contractors we interviewed."

Questions to Ask an Addition Contractor

  • How many additions have you built, and can I see some, in photos or in person?
  • Who designs the addition: you, an architect I hire, or a designer you work with?
  • Who handles the structural engineering, permits and any zoning or septic approvals?
  • Who will be on site day to day, and who is my main contact?
  • Which trades are your own crew and which are subcontractors?
  • How will you protect the house and keep it weathertight when you open the exterior wall or roof?
  • Will we be able to live in the house during construction?
  • How are changes priced once work starts?
  • What is the schedule, and what could move it?

Comparing Quotes and Contracts

Cost Breakdown

Ask every contractor to price the same plans and specifications, and to list what is included and what is not. On additions, the items most often left out or priced differently are engineering, permit fees, excavation surprises such as ledge, heating and cooling for the new space, an electrical service upgrade, and site restoration and landscaping afterward.

Allowances and Materials

If cabinets, tile, flooring or fixtures are not chosen yet, a quote will carry allowances. Compare the allowance amounts, not only the total: a low bid with thin allowances can end up costing more.

Payment Schedule

Payments should follow progress, for example at the foundation, framing, rough-in inspections and completion, rather than a large sum up front. In Massachusetts, home improvement law (M.G.L. chapter 142A) generally limits the deposit to one-third of the contract price or the cost of special-order materials, whichever is greater.

Change Orders

Plans change on almost every addition. The contract should say how changes are priced and approved in writing. Virginia T. of Andover wrote: "As with all jobs, there were a number of changes and add-ons and we believe Ryan always gave us a reasonable price." Roland M. of North Andover described another approach: "we started with a minimum design at a very reasonable cost. Then we were able to work with you to add features and modifications as we went along."

Timeline

Ask for an estimated start and completion date and what the contractor will do if weather or materials hold things up. As a guide, our renovation process guide puts a home addition at 3 to 9 months of work.

Design-Build or Architect First?

You can hire an architect to draw the addition and then put the plans out to bid, or hire a design-build company that handles design and construction under one contract. With design-build, the budget is part of the design conversation from the start, and one team is responsible from the first meeting to the final walk-through. That is how we work: an initial consultation on budget, needs and time frames, design with designers and architects, then an experienced project manager runs the build. Our guide to comparing design-build companies covers how to choose that kind of firm.

From Our Projects

Don Z. of Newburyport wrote: "Norman Builders did a fantastic job with our home addition project." Read more on our customer reviews page.

Frequently Asked Questions about Contractor Home Additions

Who pulls permits on a home addition?

In a full-service arrangement the contractor schedules the work, pulls permits and books inspections. Ask in writing who handles the structural engineering, permits and any zoning or septic approvals, and whether permit fees are in the price.

How much does a home addition cost in Massachusetts and New Hampshire?

It depends mostly on whether you build out or up and how many rooms with plumbing you add. Our home addition cost guide breaks the factors down.

What is the difference between an addition and a renovation?

An addition expands the house: new floor area with its own foundation or a new level, framing, roof and exterior. A renovation changes space you already have, such as a kitchen, bathroom or layout, without adding square footage. Many projects are both, because joining an addition to the house usually means reworking the rooms next to it. That is why it pays to hire a contractor who does both kinds of work.

What is the most cost-effective way to build an addition?

Settle the design before construction starts, keep rooms with plumbing close to existing plumbing, and add only the space you will use. A small bump-out or finishing space already under a roof, such as an attic that can meet code or the area over a garage, avoids a new foundation. Comparing detailed bids on the same plans also keeps the price honest. HomeGuide puts most bump-outs at $5,000 to $35,000; see our guide to the cost to bump out a living room.

Talk to an Addition Contractor

If you are planning an addition in the Merrimack Valley, the North Shore, the Seacoast or southern New Hampshire, call Norman Builders at (978) 833-7337 or request an estimate. We typically respond the same day or within 24 hours.