Permit
Expect a building permit
Massachusetts exempts sheds, fences and finish work from permits (R105.2), not roofing. The application to Lexington’s building department carries the contractor’s HIC number (R105.3).
Roof Replacement in Lexington, MA
Half of the 12,754 homes in Lexington were built before 1965. What the code requires when that roof is replaced, and who signs off, is below.
New Roofing Costs connects homeowners with independent local roofing contractors. We do not perform roofing work.
Call (833) 781-1806 Replacement and new roofs only · homeowners
This number connects homeowners who are planning a new roof or a full roof replacement with independent local roofing contractors. It is not for leak repairs or patch jobs. The call must come from the homeowner who decides on the roof. Calls may be recorded.
The rules for a reroof in Lexington
Layers
Two layers means a tear-off
A new roof may go over one existing layer; with two or more, or over slate, clay or cement tile, everything comes off to the deck (IRC R908.3.1.1). With 65% of Lexington’s homes were built before 1980, ask what is under the newest layer.
Source: IRC 2021, Chapter 9 (Pennsylvania edition, UpCodes); 780 CMR 51.00, Chapter 9 amendments
Ice barrier
Required statewide
There is no local exception: the state table says “yes.” That is a self-adhering membrane, or two cemented layers of underlayment, from the eave to at least 24 inches inside the wall line (IRC R905.1.2).
Source: 780 CMR 51.00, Chapter 3 amendments (Tables R301.2(1) and R301.2(2)); IRC 2021, Chapter 9 (Pennsylvania edition, UpCodes)
Wind and snow
118 mph design wind, 40 psf ground snow
Lexington’s code design values are a 118 mph ultimate design wind speed and a 40 psf ground snow load (30 psf minimum flat-roof snow load). At that wind speed the code calls for asphalt shingles labeled ASTM D7158 Class G or H (Table R905.2.4.1).
Source: 780 CMR 51.00, Chapter 3 amendments (Tables R301.2(1) and R301.2(2)); IRC 2021, Chapter 9 (Pennsylvania edition, UpCodes) (780 CMR 51.00, Table R301.2(2))
Rules as read on October 24, 2026. Everything else the state requires: roof replacement in Massachusetts.
Homes and roofs in Lexington
Owners live in 10,042 of Lexington’s occupied homes, or 81%. By year built, 21% before 1940, 43% before 1960, 65% before 1980; 23% went up in 2000 or later. (ACS 2020–2024.)
By building type: 74% detached houses, 9% attached single-family houses (rowhouses, twins and townhouses).
Of the 54 Middlesex County municipalities on this site, Lexington has the 24th largest share of homes built before 1980: 65%, against a county range of 29% to 87%.
ZIP codes: 02420 · 02421
Lexington and the towns around it
| Place | Median built | Before 1980 | Owners | Row, twin | Hail days |
|---|---|---|---|---|---|
| Lexington | 1965 | 65% | 81% | 9% | 8 |
| Arlington | 1945 | 86% | 62% | 7% | 9 |
| Waltham | 1961 | 69% | 50% | 9% | 7 |
| Burlington | 1972 | 62% | 74% | 3% | 9 |
| Belmont | 1938 | 87% | 65% | 6% | 11 |
| Lincoln | 1972 | 64% | 57% | 18% | 8 |
Median built: median year the homes were built. Before 1980: share of homes built then. Owners: share of homes that are owner-occupied. Row, twin: share of homes that are rowhouses, twins or townhouses. Census ACS 2020–2024. Hail days: days with hail of 1 inch or larger within 10 miles, 2006–2025, NOAA Storm Prediction Center.
Storm record around Lexington
Within 10 miles of Lexington, hail of an inch or more was reported on 8 days between 2006 and 2025, the biggest stones 2 in on August 4, 2015. The most recent was August 23, 2020.
That is fewer than most places in the state on this site (median 10 days).
Federal major-disaster declarations for storms in Middlesex County since 2006: 8, most recently DR-4379, Severe Winter Storm and Snowstorm, declared July 2018. (OpenFEMA.)
A report says hail fell near Lexington, not that it damaged a roof. When wind or hail damage means a new roof.
What goes on the roof next
Lifespans come from HUD’s capital-needs table, not from a brochure. More in the guides to shingles, metal, slate and flat roofs.
| Material | HUD useful life | Fits a house like | Watch for |
|---|---|---|---|
| Asphalt shingles | 20 years | Most pitched roofs; 74% of homes here are detached | Class G or H at 118 mph design wind (IRC Table R905.2.4.1) |
| Metal (standing seam, panels) | 50 years | Roofs that will carry solar later | Standing seam that carries its own loads can skip the tear-off (R908.3.1) |
| Slate | 75 years | Older houses; 21% here predate 1940 | Can’t be roofed over; check the framing for the weight |
| Flat roof: EPDM or TPO | 15 years | Porches, additions, low-slope rears | Where the roof meets a wall or parapet |
Checking a contractor in Massachusetts
Two numbers to ask for in Lexington: the HIC registration (M.G.L. c. 142A, for owner-occupied homes of one to four units) and the construction supervisor license (CSL) with the roof covering specialty.
The price side is in what a new roof costs in Massachusetts; the paperwork side in checking a roofing contractor.
Questions about a new roof in Lexington
Does a roof replacement in Lexington need a permit?
Expect a building permit. Massachusetts exempts sheds, fences and finish work from permits (R105.2), not roofing. The application to Lexington’s building department carries the contractor’s HIC number (R105.3).
Is a roof-over allowed in Lexington, or is it a tear-off?
A new roof may go over one existing layer; with two or more, or over slate, clay or cement tile, everything comes off to the deck (IRC R908.3.1.1). With 65% of Lexington’s homes were built before 1980, ask what is under the newest layer.
How old are the houses in Lexington?
By the Census Bureau’s American Community Survey (2020–2024), the median home in Lexington was built in 1965, 65% of homes were built before 1980, 81% are owner-occupied.
How often does hail hit Lexington?
Hail of 1 inch or larger was reported on 8 days within 10 miles of Lexington from 2006 through 2025 (NOAA Storm Prediction Center). A report means hail fell nearby, not that a roof was damaged.
How do I check a roofing contractor in Lexington?
Two numbers to ask for in Lexington: the HIC registration (M.G.L. c. 142A, for owner-occupied homes of one to four units) and the construction supervisor license (CSL) with the roof covering specialty.
What they will ask on the phone
- The street address in Lexington, or at least the ZIP code
- One story or two (or more), detached or attached
- What is on the roof now (asphalt shingles, metal, slate, tile, or a flat membrane) and roughly how old it is
- Whether there is one layer or more, if you know
- That you want a new roof or a full replacement, and when you want the work done
- Any historic-district or HOA rules on the house in Lexington
- That the house is yours and the decision is yours
The full list: before you call.