Slate pieces in the gutter or yard
Nails rusting through.
Slate roof repair in New York, NY, one slate at a time
A slate roof can outlast several generations of the people living under it, as long as broken slates are replaced and the flashing is kept up. Slate repair is careful, piece-by-piece work done from roof ladders and hooks.
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- Matched slate
- Copper flashing and snow guards
Quick answer: Slate roof repair in New York, NY means replacing slipped or broken slates one at a time with matching stone, secured with copper slate hooks or copper nails, and repairing the copper flashing at valleys, walls and chimneys. Sound slate is kept, so a slate roof rarely needs replacing because a few pieces failed.
What the job involves
Why slate is repaired, not replaced
Good slate lasts far longer than the nails and flashing that hold it. Most slate roofs fail at the fasteners and metal first: nails rust through and slates slip, and valleys or chimney flashing wear out. Replacing those parts keeps the stone in service.
Slate is also easy to damage. Walking on it cracks pieces, and roof cement or tar smeared on it makes future repairs harder and looks wrong. Replacement slates are matched by size, thickness and color.
Cost factors
What slate repair costs depends on
Number of slates
A few slipped pieces or a whole section.
Matching
Slate matched by color, size and thickness; salvaged slate where needed.
Flashing
Copper valleys and chimney flashing are skilled work.
Roof height and pitch
Roof ladders, hooks and staging on steep roofs.
Underlayment
Where flashing work exposes old felt, it is renewed.
Historic review
Landmarks approvals where the roof is visible.
Variations of the job
Slate repairs we do
Slipped or broken slates
The broken slate is removed with a slate ripper that cuts the old nails, and a matching slate is slid in and held with a copper slate hook, or a copper nail covered by a bib flashing.
Copper flashing
Valleys, chimney and wall flashings on slate roofs are usually copper or lead-coated copper. Worn or split pieces are replaced in copper so the flashing lasts as long as the slate around it.
Snow guards
Slate is slick, and snow can slide off in sheets. Snow guards fitted under the slates hold snow in place over doors, walkways and lower roofs.
Do it yourself or call
Looking after slate without breaking it
Safe to do yourself
- Inspect from the ground with binoculars each spring and after storms.
- Keep fallen slate pieces; they help match the replacement.
- Keep gutters clear so water and ice do not back up under the lowest course.
- Photograph any tar or cement patches so they can be removed properly.
Leave to a roofer
- Walking on the slate, which cracks it.
- Smearing roof cement or tar on slate or flashing.
- Face-nailing a replacement slate without a bib or hook.
- Clearing snow or ice from slate with shovels or picks.
Local conditions
In-Kind repair in historic districts
Ditmas Park is a historic district, so roof work on its houses goes through the Landmarks Preservation Commission, whose standard is in-kind replacement. On a slate roof that means slate matched to the original rather than an imitation product, and copper flashing wherever copper was there before. That is also what a careful slate repair does anyway, so the approval and good practice point the same way.
How it runs
How slate repair runs
- 1
Inspect without walking on it
From roof ladders, a lift or binoculars.
- 2
Source matching slate
Color, size and thickness, new or salvaged.
- 3
Replace slates
Old nails cut, new slate hooked or nailed and bibbed.
- 4
Repair flashing
Copper replaced where worn or split.
- 5
Photograph
Before and after, every repaired area.
Warning signs
Signs a slate roof needs attention
Slipped slates showing lighter stone
Pieces that have moved down the roof.
Cracked or flaking slate
Softer stone breaking down in layers.
Tar smeared on the roof
Old repairs that trap water and hide damage.
Split or holed valley metal
Flashing worn through before the slate.
Leaks around chimneys and dormers
Flashing, not slate, is the usual cause.
Questions we hear
Slate roof questions
Usually not because of a few broken slates. Good slate outlasts its nails and flashing, so repairing those keeps the roof going. Replacement makes sense when the slate itself is soft and failing across the roof.
Slate is matched by color, size and thickness. Many colors are still quarried, and salvaged slate fills the gaps for discontinued stone.
Tar on slate cracks, traps water, hides the real problem and makes the proper repair harder. The fix is replacing the slate or the flashing.
Over doors, walkways, lower roofs and gutters, they stop snow sliding off in heavy sheets. They are a common addition on slate roofs.
In a historic district or on a landmark, visible roof work generally does, and the Commission expects in-kind replacement, which like-for-like slate repair already is.
Related services
Related roofing work
Metal Roofing
Standing seam, copper and flat-seam metal installed and repaired on pitched roofs, mansards, dormers and bay tops.
Learn moreMansard Roof Repair
Slate and shingle mansards, with the dormers, gutters and flashing that come with them, repaired on steep faces most roofers avoid.
Learn moreSheet Metal Cornice Repair
Rusted and loose pressed-metal cornices resecured, patched or rebuilt in sections, with the roof edge behind them made watertight.
Learn moreSlates slipping or missing?
Call and we will match the stone and repair the roof without walking all over it.