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A deadbolt is the simplest serious upgrade you can make to a door, but the right one depends on more than how heavy it feels in the box. HMS Locksmith, based in Allston, handles deadbolt installation in Boston for homes, apartment buildings and businesses, and two questions come up again and again: what does the building code allow, and what will matter to an insurer if someone ever gets through the door?
This post answers both in plain terms. It is general information, not legal advice, so check anything specific with your local building department or your insurance agent.
Massachusetts uses one state building code
Boston does not write its own lock rules from scratch. Massachusetts uses the State Building Code, 780 CMR, and its tenth edition is based on modified versions of the 2021 International Codes. The 2021 International Residential Code is adopted, with Massachusetts amendments, for one- and two-family homes. The tenth edition took effect on October 11, 2024, with a concurrency period that ended on June 30, 2025, after which it became the only building code in effect.
For most homeowners, that means the model code language on egress doors is the starting point.
The state publishes the details in its Massachusetts State Building Code handbook.
The egress door rule and double cylinder deadbolts
The International Residential Code section on egress doors, R311.2, says that egress doors “shall be readily openable from inside the dwelling without the use of a key or special knowledge or effort.”
In practice, that affects one specific product: the double cylinder deadbolt, which needs a key on the inside as well as the outside. Hardware specialists who track the code read R311.2 as ruling out a double cylinder deadbolt on the required egress door, and our own technicians point out that these locks can be a fire hazard when someone has to get out fast in the dark.
So for the main door out of a home, the usual answer is a single cylinder deadbolt with a thumb turn inside. If you want extra protection near a glass sidelight, talk to us about reinforcing the door and frame instead of trapping the inside of the lock behind a key.
Commercial buildings follow different rules for different occupancies, and the details depend on the building. If you manage a storefront or office, ask before you swap hardware on an exit door.
How lock grades work
Deadbolts are tested to standards from the Builders Hardware Manufacturers Association (BHMA), accredited by ANSI.
- ANSI/BHMA Grades 1, 2 and 3. Grade 1 is the highest. Grades 2 and 3 are generally treated as residential grade.
- ANSI/BHMA A156.40. A residential deadbolt standard that gives separate letter grades for security, durability and finish, where A is best and C is good.
A grade on the box is a useful starting point, not the whole story. Installation decides a lot of what the lock can actually do.
The ANSI/BHMA grade levels page from the Builders Hardware Manufacturers Association explains the three tiers.
Installation details that matter
A strong lock fastened into a weak frame is still a weak door. When we install deadbolts, we pay attention to:
- Strike plates. Heavy-duty strike plates fastened with extra-long screws that reach past the trim into the framing.
- Cylinder choice. Bump-resistant spool pins are a sensible step up from standard pin tumblers on commercial doors.
- Fit and alignment. A bolt that drags or only half-throws is a bolt people stop using.
- High-security options. We install high-security deadbolts from makers such as Medeco and Mul-T-Lock, with key duplication controlled by an authorization card and a log of every key made.
You can see the full range on our deadbolts and high-security locks page.
What insurers look at after a break-in
We cannot tell you what your policy requires, because every policy is different and some have their own conditions about locks or alarms. Read yours, or ask your agent, before you assume anything.
What we can say is that documentation matters when you make a claim. Photograph forced entry points, broken glass and damaged property at the scene before anything is repaired, and keep the locksmith’s invoice showing what was replaced.
After a break-in, call the police first, take your photos, and then call us to repair or replace the damaged lock and frame. Keep the invoice. It shows what was repaired and when.
Serving Somerville, Boston and nearby towns
We install and repair deadbolts across Boston neighborhoods such as Allston, Brighton, Dorchester and Charlestown, and in surrounding cities including Somerville, Cambridge and Everett. Our Somerville locksmith page has more about service in that city.
Frequently asked questions
Can I put a double cylinder deadbolt on my front door in Massachusetts?
The model residential code that Massachusetts builds on requires egress doors to open from inside without a key, which rules out a double cylinder deadbolt on the required exit door. Check with your local building department for your situation.
Is a Grade 1 deadbolt always better for a house?
Grade 1 is the highest ANSI/BHMA grade, but a well-installed Grade 2 lock with a reinforced strike is a solid choice for most homes. How the lock is fitted matters as much as the grade.
What should I do with the old lock after a break-in?
Photograph it in place before anything is removed, then keep it until your claim is settled in case the adjuster wants to see it.
Trusted Local Network
We like to point readers toward businesses that do careful work in their own trades and markets. Two worth a look:
- A Houston garage door company explains how garage door openers and remote replacements fit into overall home access, worth reading if a remote ever goes missing with your keys.
- A public adjusting firm working in California, Arizona and Connecticut advises photographing forced entry points and damaged property at the scene in its guide to theft and vandalism insurance claims.
Your Greater Boston Deadbolt Specialists
If you are planning a deadbolt installation or need a lock repaired after a break-in, reach our team through the contact page to talk through the door and the options. Call (617) 249-4949 and we will discuss all fees before any work begins.
HMS Locksmith is based in Allston and serves Boston and nearby communities across Suffolk, Middlesex, Norfolk and Essex counties, including Cambridge, Somerville, Brookline, Newton and Quincy. Learn more about our deadbolt and high-security lock installation, or see what neighbors say in the HMS Locksmith Google reviews before you book.
