Repair or replace? How we judge a 100-year-old slate roof
Most slate roofs that leak are not worn out. Here is the survey method our slaters use to decide between restoration and replacement.
Walter Kowalczyk, Master slater
Slate, copper and historic roofs across Greater Boston
Boston roofs, laidby hand since 1962.
Four crews and a copper shop restoring slate, soldering copper and replacing roofs on the city's oldest houses.
4.9 from 1,137 homeowner reviews (sample)
Porch and main roof, Milton
Slate mansard, Back Bay
Colonial Revival, Brookline
Six decades of Boston roofs, by the numbers
- Years on Boston roofs
- 64
- Roofs restored or replaced
- 4,860+
- Historic district projects
- 212
- Rating from 1,137 reviews (sample)
- 4.9
Ten services, one standard of care
From a single cracked slate to a full copper-and-slate restoration, the same foremen, the same materials and the same written reports.
View all ten servicesSlate Roof Restoration
Hand-slated repairs and full restorations that keep 100-year-old Vermont and Welsh slate on the roof.
ExploreCopper Gutters & Flashing
Soldered copper half-rounds, built-in box gutters, bay roofs and chimney flashing made in our own sheet metal shop.
ExploreRoof Replacement
Full tear-off and replacement in slate, architectural shingles, cedar-look synthetics or standing seam metal.
ExploreRoof Repair
Leak tracing and lasting repairs for slate, shingle, flat and metal roofs, usually scheduled within a week.
ExploreStorm & Hail Damage
Nor'easter, wind and hail damage assessment, emergency tarping and insurance-ready documentation.
ExploreFlat & Commercial Roofing
TPO, EPDM and modified bitumen for triple-decker rooftops, roof decks, condos and mixed-use buildings.
Explore
The craft behind a hundred-year roof
Nothing on these roofs is caulked, glued or rushed. These are the habits that make restorations last.
Copper nails. Only.
Iron nails rust through in 70 years. Copper lasts as long as the stone it holds.
19 years
Average experience of our slate and copper crew
25 years
Workmanship warranty on slate restoration (sample)
BeforeAfterLouisburg Square, Beacon Hill
81 percent of the original slate, saved
Two contractors recommended a tear-off. Our survey counted 2,140 sound slates on an 1846 mansard. Drag the slider to compare.
- ScopeMansard restoration, copper dormers and valleys
- Roof size24 squares, four stories
- Timeline5 weeks, commission approved at staff level
- ResultDry through two nor'easters the next winter
Six materials, honestly compared
Lifespan, installed cost and wind rating for the roofs we install most. Handle the swatches and samples in our materials library.
Open the materials library| Material | Typical lifespan | Installed cost | Wind rating | Weight | Best for |
|---|---|---|---|---|---|
| Natural slate | 75 to 150 years | $1,800 to $3,200 per square | Up to 110 mph with proper nailing and hooks | 800 to 1,500 lb per square | Historic homes, mansards, steep roofs built to carry the weight |
| Standing seam metal | 40 to 100 years | $1,150 to $2,600 per square | Tested to 140 mph and above (double-lock) | 100 to 150 lb per square | Porches, bays, low-slope additions and snow country |
| Copper | 80 to 120 years | $2,400 to $4,200 per square | Up to 130 mph with cleated seams | 100 to 130 lb per square | Bay roofs, dormers, cupolas, gutters and flashing |
| Architectural shingles | 25 to 35 years | $520 to $780 per square | 110 to 130 mph with enhanced nailing | 250 to 450 lb per square | Colonials, capes and budget-conscious replacements |
| Clay and concrete tile | 50 to 100 years | $1,000 to $2,100 per square | Up to 125 mph with foam or mechanical fastening | 600 to 1,100 lb per square | Mediterranean and Tudor revival homes in Brookline and Newton |
| TPO and EPDM membranes | 20 to 30 years | $780 to $1,450 per square | FM-rated assemblies to 90 psf uplift and higher | 30 to 60 lb per square plus insulation | Triple-deckers, roof decks, condos and mixed-use buildings |
Natural slate
- Typical lifespan
- 75 to 150 years
- Installed cost
- $1,800 to $3,200 per square
- Wind rating
- Up to 110 mph with proper nailing and hooks
- Weight
- 800 to 1,500 lb per square
- Best for
- Historic homes, mansards, steep roofs built to carry the weight
Standing seam metal
- Typical lifespan
- 40 to 100 years
- Installed cost
- $1,150 to $2,600 per square
- Wind rating
- Tested to 140 mph and above (double-lock)
- Weight
- 100 to 150 lb per square
- Best for
- Porches, bays, low-slope additions and snow country
Copper
- Typical lifespan
- 80 to 120 years
- Installed cost
- $2,400 to $4,200 per square
- Wind rating
- Up to 130 mph with cleated seams
- Weight
- 100 to 130 lb per square
- Best for
- Bay roofs, dormers, cupolas, gutters and flashing
Architectural shingles
- Typical lifespan
- 25 to 35 years
- Installed cost
- $520 to $780 per square
- Wind rating
- 110 to 130 mph with enhanced nailing
- Weight
- 250 to 450 lb per square
- Best for
- Colonials, capes and budget-conscious replacements
Clay and concrete tile
- Typical lifespan
- 50 to 100 years
- Installed cost
- $1,000 to $2,100 per square
- Wind rating
- Up to 125 mph with foam or mechanical fastening
- Weight
- 600 to 1,100 lb per square
- Best for
- Mediterranean and Tudor revival homes in Brookline and Newton
TPO and EPDM membranes
- Typical lifespan
- 20 to 30 years
- Installed cost
- $780 to $1,450 per square
- Wind rating
- FM-rated assemblies to 90 psf uplift and higher
- Weight
- 30 to 60 lb per square plus insulation
- Best for
- Triple-deckers, roof decks, condos and mixed-use buildings
Swipe to compare all 6 materials
Roofing materials compared on lifespan, installed cost per square and wind rating. Figures are sample ranges for Greater Boston.
Recent restorations
Beacon Hill slate, Cambridge copper, a Brookline replacement with fourteen valleys and a Jamaica Plain flat roof that finally drains.
See all projects
4.9 average from 1,137 reviews (sample)
What our neighbors write back
Every review comes from a verified job. We read all of them, including the four-star ones.
Read all reviewsTwo companies told us the slate was finished. Walter's crew saved most of it, matched the rest and the commission approved it without a hearing.
Eleanor Whitcombe, Beacon HillSlate restoration, March 2026
The new copper conductor heads are copied from an 1889 original. Our painter could not tell which pieces were new.
Ravi Chandrasekar, CambridgeCopper gutter relining, November 2025
Fourteen valleys, twelve days and not one nail left in the driveway. Mateo sent photos every evening.
Priya Okafor, BrooklineRoof replacement, October 2025
Our condo board got a clear scope and schedule. The roof drains now and the top unit is finally dry.
Marisol Figueroa, Jamaica PlainFlat roof replacement, August 2025
This season's offers
Mention the code when you book. All offers are sample promotions for this demo site.
- Free
Copper flashing check with any chimney repair
We inspect and photograph chimney and wall flashing at no charge when you book any chimney repair.
Mention code FLASH-CHECK
Valid through December 31, 2026 (sample)
Claim with an inspection - $750
Off a full slate restoration
For restorations over 10 squares booked before the first snow. One offer per property.
Mention code SLATE-750
Book by November 15, 2026 (sample)
Claim with an inspection - 15%
Gutter guards with new gutters
Save on stainless micro-mesh guards when installed with a new gutter system.
Mention code GUARD-15
Valid through October 31, 2026 (sample)
Claim with an inspection
Dorchester Avenue shop
418 Dorchester Avenue, Boston, MA 02127
Crews dispatched daily within about 25 miles
Directions and hoursRooftops we know by name
Six neighborhoods and towns, more than 3,600 roofs between them. Pick yours to see the housing stock, commissions and common repairs we see there.
- Beacon Hill & Back Bay640 roofs
- Cambridge710 roofs
- Brookline530 roofs
- Newton820 roofs
- Jamaica Plain590 roofs
- Milton380 roofs
Also serving Somerville, Dorchester, West Roxbury, Arlington, Belmont, Needham, Quincy, Hingham and nearby towns.
From the journal
Notes from the roof
Written by the slaters, coppersmiths and foremen who do the work.
All articles
Questions we hear every week
Can't find yours? See all FAQs or call (617) 555-0232.
Yes. Standard inspections are free for owner-occupied homes in our service area, with a photo report emailed within two business days. Detailed pre-purchase and association surveys are priced separately.
If most slates ring solid when tapped and are not flaking, restoration is usually the better value, often 35 to 60 percent of the cost of a new slate roof. Our survey counts the salvageable slate so you can decide with real numbers.
In local historic districts such as Beacon Hill, Back Bay and parts of Cambridge and Brookline, visible roof changes typically need review. Like-for-like repair is often approved at staff level. We prepare applications and samples for you.
Most single-family replacements take 2 to 5 working days. Slate, copper and large complex roofs can take 2 to 6 weeks. You get a written schedule before work starts.
Yes, through third-party lenders with terms from 5 to 15 years, subject to credit approval. Our financing page has a sample payment estimator.
We hold a Massachusetts Construction Supervisor License and Home Improvement Contractor registration, with general liability and workers compensation coverage. License numbers on this demo site are placeholders.
Let's look at your roof together
A free photo inspection, a straight answer on repair or replacement, and a written estimate within the week.
Licensed and insured in Massachusetts. No-pressure estimates (sample).