Boston & North Shore Roofing
Slate Roof Repair in Boston, MA
Most slate roofs in Boston are not worn out. The nails rusted, the flashing gave up, or somebody patched them with tar. We repair slate as slate: matched stone, copper fasteners, and Landmarks approval handled before the permit.
- Broken slates cut out with a ripper
- Copper hooks and bibs, never face nails
- Salvaged slate matched to your field
- Landmarks approval filed before the permit
Slate outlives everyone who works on it. A Boston roof laid in 1890 can still be sound today. What fails first is almost never the stone. It is the nails, the flashing, and whatever the last contractor smeared on with a trowel.
So the first job is telling you which you have. A roof dropping slates is often decades from replacement. A roof whose slate is delaminating is not.
We repair slate, copper and cedar across Boston and the surrounding towns.
- Broken slates cut out with a ripper
- Copper hooks and bibs, never face nails
- Salvaged slate matched to your field
- Landmarks approval filed before the permit
Free Slate Roof Repair & Restoration Estimate
Know The Signs
What a failing slate roof actually looks like
Slate gives warning before it fails. These are the signs worth a call.
Slates on the ground after a thaw
One slate in the driveway is a nail that rusted through. A dozen over a winter means the fastening layer is going.
Faces flaking or splitting in layers
That is delamination. The slate splits along its own grain, softens at the corners and thuds when tapped. Spent slate has spent neighbors.
Rust streaks down the field
Galvanized valleys and step flashing rot out under stone that still has 50 years in it. The metal dies first.
Black tar patches over cracks
Roofing cement shrinks as it cures, traps water against the stone and pulls the next slate loose.
A leak that only shows in driven rain
Short headlap or an open sidewall. The roof sheds a vertical downpour fine and lets a nor'easter in sideways.
Ridge or hip caps lifting
The bedding mortar under the ridge has washed out. Wind gets underneath and walks the caps loose.
The stone lasts. The nails do not.
Quarried slate lasts generations. The iron nails holding it up do not. They corrode, thin and let go, and slates slide off one at a time. Slaters call it nail sickness.
Flashing runs the same clock and gives out around 30 to 50 years. Replace the metal and the roof keeps going. Strip sound slate because the flashing failed and you throw away half a century of roof.
Reading your slate before anyone quotes it
- Thickness and size — a 3/16 inch commercial slate is not a 1/4 inch quarry slate
- Sound — good slate rings when tapped, spent slate thuds
- Edges — flaking and softening mean the mineral is breaking down
- Quarry — Monson black and unfading Vermont green outlast softer stock from the same decade
Repairs that quietly ruin a slate roof
- Tar troweled over cracks, which shrinks and takes the next slate with it
- Face-nailing a replacement through the exposed surface, then caulking the head
- Asphalt shingles patched into a slate field
- Steel or galvanized fasteners set against copper
- Walking the field unstaged, which cracks slates three courses from the leak
Copper, and why the fasteners have to match
Copper flashing with galvanized nails is a small battery: the metals corrode each other and the cheaper one loses. We fasten copper with copper, the standard for slate and cedar. Near saltwater in Marblehead, FEMA guidance calls for 300-series stainless within 3,000 feet of the shore.
Step flashing, counter flashing, valley pans and chimney crickets are fabricated in copper, the same shop work behind our standing-seam copper roofing and chimney flashing repair.
A mansard hides a second roof
Back Bay filling began in 1857, and its blocks carry a continuous mansard: slate on the near-vertical face, low-slope membrane on the flat top behind it. Water past that transition lands inside the wall, not on the deck. The fix is slate plus flat roof membrane replacement above.
Review first, permit second
In a Boston Landmarks district, approval lands before ISD issues the roofing permit. That covers the Historic Beacon Hill District, established 1955 and the first in Massachusetts, plus Back Bay, the South End and Bay Village. Slate color, size and exposure are all reviewable.
When slate is genuinely finished
Massachusetts never allows shingling over slate, tile, wood shake or asbestos-cement tile. It all comes off. What goes back gets the R905.1.2 ice barrier: eave to 24 inches inside the exterior wall line, 36 inches along the slope at 8:12 or steeper.
Our Process
How we repair a slate roof
Slate work is slow and runs in a fixed order. Rushing a step breaks stone.
Roof walk and slate sounding
Paulo goes up on staging or a hook ladder, taps slates, counts broken and slipped units, and checks the attic side.
Identify the stone
Quarry, thickness, size and exposure. That is what tells you whether the roof has another 50 years in it or five.
Source the match
We pull from salvage stock and current quarries to match color, size and thickness. A mismatched patch shows from the street forever.
Historic approval, then the permit
In a Landmarks district, approval lands before ISD issues anything. We file it. Here is [how Boston historic district roof approval works](/blog/boston-historic-district-roof-approval-beacon-hill-back-bay/).
The repair itself
A ripper cuts the old nails out from under the course above. The new slate goes back on a copper bib or hook.
Metal, mortar and a final sounding
Spent flashing replaced in copper, ridge bedding repointed, then we sound every course around the work to catch anything cracked.
On The Roof
What slate roof repair & restoration looks like in progress
What Drives The Price
What drives slate roof repair cost in Boston
Slate pricing has little to do with square footage. It is access, matching, and how much metal comes out.
Slate or flashing
Swapping twenty slates is a morning. Rebuilding a copper valley buried under a hundred courses of stone is another job entirely.
Matching the existing field
Color, size, thickness and quarry all have to line up. Salvaged stock can cost more than new and takes time to find.
Access and staging
[Beacon Hill](/service-areas/beacon-hill-boston-ma/) has one-way brick streets, no dumpster space and party walls both sides. Staging can outrun the roofing.
Pitch and mansard face
Steep slate needs staging or hook ladders, and nobody walks a mansard face. Curved South End bowfronts need slates cut to a template.
Copper fabrication
Flashing prices by metal weight and piece count. A chimney with a cricket is several fabricated pieces, not one.
Historic review
A Certificate of Appropriateness means an application, photos and a hearing date. Real hours before anyone climbs.
These are Greater Boston cost drivers, not a quote. Nobody prices slate off a photo. Paulo sounds the stone and tells you which job you have.
FAQ
Slate Roof Repair & Restoration questions we get asked
Straight answers, including the ones that cost us work sometimes.
Yes, and that is most of what we do. Slates come out with a ripper and go back on a copper hook or bib.
By quarry, color, size and thickness, salvage first. If nothing matches the street side, we rob slates from a hidden slope and set the new stone there.
Up front, usually. Over 40 years, rarely. Removal prices by weight, and asphalt buys two or three roofs in the time slate needs none.
In a Boston Landmarks district, likely yes, even for in-kind repairs on a visible slope. We file it, or reach the commission at 617-635-1935.
Yes. Cedar and slate share rules: copper nails, no tar, and metal that does not fight the fasteners. Neither can be roofed over.
Related roofing services
Work that often comes up on the same roof.
- Flashing & Chimney RepairStep, counter and cricket flashing rebuilt at chimneys, sidewalls and parapets. Crown and mortar repair above the roof line, water tested before we leave.Learn more
- Standing Seam Metal RoofingStanding seam and flat-lock metal in coated steel, aluminum and copper. Concealed clips, soldered pans, clamp-on snow guards, stainless fasteners near saltwater.Learn more
- Roof InspectionsFree, documented roof inspection. We get on the roof, check the attic, and hand you photos, a written report, and an honest verdict.Learn more
Read more before you decide
Longer guides on the parts of this that homeowners ask about most.
- Historic RoofingReplacing a Roof in Beacon Hill, Back Bay or the South End: Landmarks Commission Approval FirstDesign review is not a formality you handle later — Boston is explicit that Landmarks approval comes before the building permit. Here are the districts, what gets reviewed on a roof, and how to sequence the job.6 min read
- MaterialsHow Long Does a Roof Last in New England? Lifespan by MaterialManufacturer lifespans are written for a mild climate. Here is what asphalt, slate, metal, cedar and membrane actually deliver in a place with 69 freeze-thaw days a year — and the five things that cut those numbers short.6 min read
Slate Roof Repair & Restoration across Greater Boston
We run this service in 34 communities. Here is where it comes up most often:
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