Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
ROOFING INSPECTION & REPAIR
AMERICAN CEMWOOD ROOFING
BEST ROOFING PRACTICES
BUILT UP ROOFS
CATHEDRAL CEILING VENTILATION
CERTIFICATIONS for ROOFING CONTRACTORS
CHIMNEY FLASHING Mistakes & Leaks
COLD WEATHER ROOF TROUBLE
DECKS, ROOFTOP CONSTRUCTION
EPDM, RUBBER, PVC ROOFING
EXTRACTIVE BLEEDING on SHINGLES
FIRE RETARDANT PLYWOOD
FLASHING on BUILDINGS
FLAT ROOF MOISTURE & CONDENSATION
GREEENHOUSE / SOLARIUM ROOF LEAKS
HEAT TAPES & CABLES for ROOF ICE DAMS
ROOF ICE DAM LEAKS
MASONITE WOODRUF FIBERBOARD ROOFING
NOISE CONTROL for ROOFS
PLASTIC ROOFING TYPES
PVC, EPDM, RUBBER ROOFING
ROOF ARCHITECTURAL STYLES - PHOTO GUIDE
ROOF CLEANING RECOMMENDATIONS
ROOF COLOR RECOMMENDATIONS
ROOF INSPECTION SAFETY & LIMITS
ROOF LEAK DIAGNOSIS & REPAIR
ROOF NOISE TRANSMISSION
ROOF REPLACEMENT SNAFUs
ROOFING FELT UNDERLAYMENT REQUIREMENTS
ROOFING MATERIALS, Age, Types
SADDLE CONSTRUCTION at CHIMNEYS
SNOW GUARDS & SNOW BRAKES
STANDARDS for ROOFING
STRESS SKIN INSULATED PANELS
TEST LABS - ROOF SHINGLE
TREES & SHRUBS, TRIM OFF BUILDING
TRUSSES, FLOOR & ROOF
UNDERLAYMENT REQUIREMENTS on ROOFS
VENTILATION in BUILDINGS
WALK-ON ROOF SURFACES
WARRANTIES for ROOF SHINGLES
WORKMANSHIP & ROOF DAMAGE
How to repair a leaky slate roof: how to replace missing, cracked, or damaged roofing slates. This article explains how to remove and replace individual slates during repairs to a leaky or damaged slate roof. By using copper tabs or slate hooks it is possible to replace just a single roofing slate where needed.
We describe methods for repairing all sorts of leaks or other problems in slate roofs, and we include a photo guide to repairs in slate roofs. Photographs illustrate how to replace or patch broken, missing, or cracked roofing slates. This slate roofing repair photo library shows various kinds of roofing slate repairs for common defects.
Green links show where you are. © Copyright 2015 InspectApedia.com, All Rights Reserved.
This article series describes describing procedures for evaluating the condition of slate roofing and for repairing leaky or damaged slate roofs. How to inspect, identify defects, and estimate remaining life of slate roofs are addressed.
The abandonment of good slate roofs which should have been repaired is a financial shame and the destruction of a valued asset. At the same time, careless optimism about a bad slate roof which is at the end of its life risks an angry inspection client. This article reviews some slate roof repair tips. We also provide slate sources and where to buy slate roofing materials and slate roofing tools and products.This text deals with repairs to damaged slate roofs as compared with complete new slate roof installation. A key difficulty is presented by the fact that unlike asphalt shingles, slates are rigid. The repair person cannot easily "lift" adjacent slates to install the fastener for the new replacement slate.
[Click to enlarge any image]
Cover the new nail with a copper "bib" which is slid up under the covering or overlaying slates to cover the nail hole
and to extend up below the next upper covering slate whose bottom edge covers the upper portion of the gap through which the nail was
placed. the copper bib should have its edges burred, or should be bent slightly so that it will not slide out.
This alternative slate roof fix procedure uses 3" stainless steel slate hooks distributed by Vermont Structural Slate (and possibly other companies).
Stainless steel slate hooks offer a more reliable alternative than copper strips for holding replacement slates in place.
The fastener end of the hook is nailed roughly 3" up from what will be the lower edge of the replacement slate.
The slate is slid up over the hook and seated. The illustrations below depict this easy two-step roofing slate replacement procedure.
Slate hooks are available from John Stortz & Son Inc and other suppliers.
Replacing Lost Roofing Slates - How to Secure the New Slate
Lost slate replacement, re-using a slate salvaged from elsewhere is a reasonable repair, but if going to the trouble of replacing a roofing slate, let's use a replacement slate that itself is in good condition.
Note the exposed nail hole which would have been covered by the next course in the original placement of this slate used for a repair. It is certainly expedient to keep old, good-condition roofing slates left over from a prior repair or from another source, using them to replace broken or lost slates on an existing roof.
Red slate roof, generally excellent condition is shown in our photo at left.
But with broken damaged slates at eaves, possibly during ice damming or installation of heat tapes. Heat tapes at a roof edge are themselves evidence that the building has experienced a problem with ice dams and leaks at the eaves.
Red roofing slates like this, if observed in the Eastern half of North America, probably came from the NY/VT Granville slate quarry.
Repair of Holes & Nail Pops in Slate Roofs
Slate roof hole repair, using copper slid up below perforated slates is illustrated in our photo at left. Copper is a durable repair metal that can provide a long term repair for problems like this one. The slate in the center of the photo is broken by both a hole and a crack.
Repair: Slate repair with aluminum, on a slate roof with a coating of lichens
A simple piece of flat aluminum flashing was pushed up under the slates to cover a hole3 observed by the roof Inspector/repairman. Usually simple friction will hold this aluminum (or copper) repair plate in place for decades. Or you can put a slight Vee-bend in the metal flashing before sliding it in place if necessary.
Watch out: we're not sure how durable this particular repair will be because the poor alignment at the lower end of the slate corners between the slates at left and right over the aluminum roof patch suggest that the slate on the right may be sliding down the roof. If it's fastener has corroded away or been lost, that slate will continue to move down until a leaky opening is exposed in the roof. Keep an eye on conditions like this.
Examples of Poor Repair Work on Slate Roofs - Temporary "Fixes" to Slates
Slate roof coated with roof cement, mostly washed-off. While roof cement or mastic is not a long-term durable repair nor even a proper one for slate roofs, we'd prefer this stopgap measure to seeing someone abandon and destroy a salvageable slate roof.
The complete coating of a slate roof with roof cement or other sealants is an extreme measure and unlikely to have a long life however.
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs) about how to repair leaks in a slate roof
Questions & answers or comments about methods for removing and replacing broken or damaged roofing slates using either copper tabs or slate hooks to secure the new slate
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References
If less than 25% of the slates on a roof are damaged or sliding down from worn out nails, slate repairs are in order. Luckily replacement slates are available from a variety of slate quarries, slate suppliers, and slate roofing companies. Slate "look alike" products are also available using cementious materials. If the building owner cannot afford to repair a slate roof where most slates are intact, holding action slate roof repairs should be followed, such as simply sliding metal flashing up under broken or missing slates on the roof.
In addition to these slate sources there are several slate look-alike substitutes. While the application techniques, flashing and nailing concerns are similar, the wear characteristics of these materials may be quite different and were not evaluated for this paper. This paper is not an endorsement, nor a critique of any of these materials.