Slate roof installation and repair field guide

Slate roofing, and why a hundred-year roof fails at the metal

A slate roof is a steep-slope roof covered in shingles split from natural stone, laid in overlapping courses and hung on nails so each course laps the two below it. Installed right it is the longest-lasting roof in common use, 75 to 150 years and sometimes past 200. That number is also the trap, because it belongs to the stone, not to the roof.

The slate is the one part that does not wear out. The flashings rust, the nails corrode, and slates break where someone walked. A slate roof almost never fails in the open field. It fails at a valley that gave out at 70 years under a slate good for 150, at a fastener that rusted through, or at a course someone cracked servicing a chimney. So a hundred-year roof is only as good as its flashings and its fasteners, and the craft is matching their life to the stone's.

Installing it right comes down to a short list that does not bend. The right slate grade for the climate. Copper or stainless fasteners set to the right depth so the slate hangs and floats. Generous headlap. Copper flashings and valleys built to last as long as the slate. And the skill to pull and replace a single broken slate without disturbing the field around it.

The asphalt shingle rules carry over and so do the flashing principles, both covered in their own guides. Slate is heavier, more brittle, and far less forgiving of a short-life detail, so it gets its own playbook. Put a 30-year flashing under a 100-year slate and you have built three reroofs of flashing work into a roof that should have outlived all of them.

Real slate or synthetic slate?

Natural slate is quarried stone. Synthetic slate is a molded shingle of polymer, rubber, or a polymer-mineral blend made to imitate the look at a fraction of the weight and cost. They photograph alike from the ground and they are not the same roof.

The split runs along three lines: life, weight, and money. Natural slate lasts 75 to 150 years and beyond. Synthetic slate is generally rated for 40 to 50 years, and the real-world record on the early formulations is shorter than the brochures promised, with curling and fading showing up well inside the warranty. Natural slate runs roughly 800 to 1,500 lb per square (100 sq ft); synthetic runs about 150 to 250 lb, so it drops onto framing that could never carry stone. On cost, synthetic installs for less than half of natural in most markets, and the gap is real money on a large roof.

Pick by the building and the timeframe, not by the look. A historic structure, a roof meant to outlive its owner, framing already sized for stone, these point to natural slate. A retrofit on light framing, a tighter budget, or a roof that only has to read as slate from the street, these point to synthetic. Whichever you choose, the lifespan, the load rating, and the fastening method come from that specific product's manufacturer, not from slate lore applied to a plastic shingle.

How long does a slate roof last?

A natural slate roof lasts 75 to 150 years, and a hard first-grade slate can run past 200. No other common roof comes close. Asphalt is a 20 to 30 year roof and a standing-seam metal roof is a 40 to 70 year roof, so slate outlives both several times over.

The honest version of that answer carries a caveat, and it is the whole point of this guide. The slate reaches its century. The metal around it does not. Copper flashings and valleys in high-wear spots commonly start to pit and leak around 60 to 70 years, and old iron or galvanized nails corrode through in roughly the same window. So a slate roof that is genuinely good for 150 years will demand its first major flashing and fastener renewal at the halfway mark, and the roofs that fail early are almost always the ones where that work was skipped or done in the wrong metal.

Stated service life is a property of the grade, the quarry, and the climate, so treat any single number as a starting point and confirm the expected life of the specific slate with the quarry or manufacturer.

Slate grade and quality: S1, S2, S3

Roofing slate is graded for expected service life under ASTM C406. Grade S1 is rated for more than 75 years and in practice often far longer. Grade S2 is rated for 40 to 75 years. Grade S3 is rated for 20 to 40 years. The grade comes from three lab tests: water absorption, depth of softening under weathering, and flexural strength. The harder, denser, lower-absorption stone earns S1; softer, more absorbent stone falls to S2 or S3.

Almost all slate going onto new roofs in North America is S1, and on a roof you intend to last a century there is no reason to spec below it. The harder slate sheds water, resists the freeze-thaw cycle that delaminates softer stone, and rings when you tap it instead of giving the dull thud of a slate that is going soft.

Grade is not the only variable the quarry controls. Color, thickness, and the source seam all matter, and a slate that performs in one climate can fail in another, since freeze-thaw punishes an absorbent slate far harder in a cold wet region than in a mild one. Match the grade and the slate to the climate, and let the quarry's published test data and the manufacturer's recommendation, not a color sample, drive the specification.

One field note worth carrying: a soft slate already on a roof can be at the end of its life while a hard slate beside it has decades left. When you assess an existing roof, the grade you are standing on decides whether renewing the flashings buys 50 more years or none.

The weight, and why it is the first question

Slate is heavy, and the weight is the first thing to settle, before color, before budget, before anything. Standard 1/4 in slate laid at a 3 in headlap weighs roughly 9 to 10 lb per square foot. Half-inch slate runs near 18 to 19 lb per square foot. Most natural slate roofs land between 8 and 15 lb per square foot, and the thick graduated stone on some older roofs goes past 20.

Put that against what an ordinary roof is framed for. A typical asphalt-shingle roof structure is designed around a roof dead load on the order of 15 lb per square foot. A slate roof system, with the stone plus the deck and fasteners, commonly needs the structure engineered for something closer to 27 to 50 lb per square foot. That is not a roof you drop onto framing sized for shingles and hope.

The reroof trap is exactly this. An existing house has shingles, the owner wants the look and the life of slate, and nobody checks the framing because the roof is already there. Stone weighing two to three times what the structure was built for goes up, and the deflection, the sag, or in the worst case the failure follows. Weight is the one specification on a slate roof where the right move is to stop and bring in a structural engineer rather than guess. Confirm the dead load the actual slate imposes with the manufacturer and let the engineer confirm the structure can carry it.

Verify the structure carries the load

Do not assume the deck and the framing hold slate. On new construction the structure is designed for it from the start. On any reroof or restoration, the framing was sized for whatever was up there before, and a licensed structural engineer should evaluate the rafters, the deck, and the load path down to the foundation before a single slate is ordered.

The engineer is checking more than the rafters. The load runs from the slate into the deck, through the rafters, into the walls, and down to the footing, and a weak link anywhere on that path is where the trouble shows. Older buildings that carried slate originally are often fine. Buildings that never carried it almost always need something, whether that is sistered rafters, a heavier deck, or added support, and that scope is the engineer's call, not the roofer's.

Treat this as a hard gate. The slate, the fasteners, and the flashing are all reversible mistakes you can fix on the roof. An overloaded structure is not, and it is the one slate failure that endangers the people under it. Get the load verified and the upgrade designed before the tear-off, and put the engineer's stamp in the project file.

What is the minimum slope for a slate roof?

Slate is generally not laid below a 4:12 slope. The stone sheds water, it does not seal against it, so it needs enough pitch to move water off the surface before it backs up under a course. The NRCA framework for steep-slope materials starts at 4:12, and that is the common floor for slate as well.

Slope and headlap work together, and that is where the manufacturer's table earns its keep. As the pitch drops toward the minimum, water travels slower and has more chance to drive back uphill under the slates, so the headlap goes up to compensate. Steeper roofs shed faster and can run a shorter headlap. Push the slope toward 4:12 and you increase the lap; build a steep 12:12 and you can ease it within the limits the manufacturer sets.

Below the minimum the answer is not a tighter lap, it is a different roof. Water that gets under slate on a too-shallow pitch sits on the underlayment and finds the fasteners, and no amount of headlap fixes a slope the stone was never meant to run on. Confirm the minimum slope and the matching headlap for the specific slate against the manufacturer and the adopted code.

What is headlap and exposure on a slate roof?

Headlap is the distance the third course overlaps the first, the part of a slate covered by the two courses above it. It is what makes the roof watertight, because at every horizontal line across the roof there are three thicknesses of stone, and water working down a joint between two slates lands on the solid slate of the course below rather than on a nail or a seam.

The standard headlap is 3 in, and slate is sold by the square at that lap so a square covers 100 sq ft when laid with a 3 in overlap. Modern codes commonly call for at least a 4 in headlap on slopes from 4:12 up to 8:12, easing back toward 3 in only on steeper roofs. The lower the slope, the more lap.

Exposure, the amount of each slate left showing to the weather, falls straight out of the headlap. Subtract the headlap from the slate length and divide by two. A 24 in slate at a 3 in lap gives an exposure of (24 minus 3) divided by 2, which is 10.5 in. Get the exposure wrong and you have either wasted slate or, far worse, shorted the headlap and built a roof that leaks at every joint. Lay out the coursing off the exposure, snap your lines, and keep the joints in any one course offset from the joints two courses down so water never runs a straight path to the deck.

Headlap is the number to hold to the manufacturer and the code. When the slope, the slate length, or the local exposure to wind-driven rain is unusual, the published headlap table governs, not the 3 in default.

The deck and the underlayment

Slate goes over a solid deck that holds a nail. On older roofs that often meant spaced or solid wood boards; on new work it is typically solid wood sheathing rated to take the fasteners and the load. The deck has to be sound, because the slate is only as well anchored as the wood the nails bite into, and a punky board lets fasteners pull no matter how good the slate is.

The underlayment is the secondary water barrier under the stone, and on a roof meant to last a century it should be chosen to last as long as the rest of the assembly. Traditional slate ran over rosin paper or felt, but felt that breaks down in 20 to 40 years becomes the weak layer under a 100-year slate. Heavier felts and synthetic or self-adhered membranes hold up longer and earn their place at the eaves, in the valleys, and anywhere water backs up. The underlayment choice, like the rest of the system, is covered in more depth in the steep-slope and flashing guides; the rule for slate is to not put a short-life membrane under long-life stone.

One detail people miss: the underlayment is a backup, not the waterproofing. The slate and the flashings keep the water out. The underlayment buys time when something upstream fails, and it protects the deck during construction before the slate is on.

What fasteners are used on a slate roof?

Copper or stainless steel. Those are the two fastener metals that belong on a slate roof, and the reason is simple arithmetic: the slate lasts a century, so the nail has to last a century too, and only copper and stainless do. Each slate takes two nails.

Galvanized is where slate roofs die young. A hot-dipped galvanized nail rusts through in a fraction of the slate's life, and once the nails go, the slates slide off in sheets no matter how good the stone is. There is a second reason to ban galvanized on a slate roof: copper flashing is standard, and a galvanized fastener in contact with copper sets up galvanic corrosion that eats the steel even faster. Use copper nails or stainless nails, one metal or the other, and keep dissimilar metals apart. Do not mix galvanized with copper anywhere on the roof.

Think of the fastener as the life limit of the whole roof. You can pick the hardest S1 slate in the quarry, but if you hang it on a nail that fails in 60 years, you have built a 60-year roof out of 150-year stone. The fastener decision is not a place to save a few dollars per square. It is the decision that sets how long the roof actually lasts.

Nailing: hang the slate, do not clamp it

Slate is hung on its nails, not clamped down by them. The slate has to float, expanding and contracting and shifting slightly with the deck without the fastener fighting it. Two nails per slate, driven through pre-punched holes, set so the head just kisses the slate and no more.

Overdriving is the most common way to crack slate during installation, and it does its damage two ways. The hammer head hits the slate face and chips or fractures it, and the overdriven nail springs the slate into a slight concave dish, loading it so it splits later under a snow load, a thermal move, or wind. Underdriving is the other failure: a nail head left standing proud holds the overlying slate up off its bed, cracks it when the next course settles onto the bump, and gives wind-driven rain a path in. The target is narrow. The head sits flush with the slate surface, touching but not biting.

The holes are pre-punched, usually at the quarry, set in from the edges and roughly a quarter of the slate's length down from the head, which puts the fasteners in the nailing zone covered by the courses above. Field-punch a hole when you have to with the punch on the slate cutter, working from the back so the countersink ends up on the face to receive the nail head. Keep the nails inside the zone the upper courses cover, because a nail set too low ends up exposed and rusting in the weather. Hang them right and the slate floats for a century. Crush them and you have seeded the roof with cracks that show up years after you are gone.

Copper flashing, matched to the life of the slate

Flash a slate roof in copper. The flashing is where slate roofs leak, so it is where the money and the metal choice matter most, and the only flashing worth putting under a 100-year slate is one with a comparable life. Copper is the standard. It works, it patinas instead of rusting, and it lasts in the same range as the stone.

The mistake that defines failed slate roofs is short-life flashing under long-life slate. A painted-steel or aluminum flashing that fails in 20 to 30 years means the roof gets opened up and reflashed several times over the slate's life, every time disturbing the field and risking the slates around the work. Worse, a non-copper flashing in contact with copper nails or copper valleys corrodes galvanically. Keep the flashing metal consistent with the fasteners, copper to copper, and the roof leaks far less and lasts far longer.

Where the flashing goes and how each piece sheds over the one below it is the subject of the flashing guide, and those principles apply unchanged to slate. The slate-specific rule is the metal and the life: copper, sized and detailed to outlast the renewal cycle, never a cheaper metal that turns the roof's strongest asset into a maintenance schedule.

Valleys: open copper, sized for the water

Valleys carry the most water on the roof and wear out first, so on slate they are detailed as open copper. An open valley leaves a channel of exposed copper down the center with the slate cut back on each side, which lets water and debris run clear instead of jamming under the stone. Heavy-gauge copper is worth it here, because the valley is the spot that pits and leaks decades before the field does.

The W-valley, with a raised crimp formed down the centerline, is the standard detail on slate. The center rib stops water sheeting across from one slope from driving up under the slate on the other side during a hard rain, which a flat valley lets happen. Size the valley width to the catchment above it; a long, steep roof draining into a short valley overruns a channel that was sized by habit instead of by area.

Debris is what shortens a valley's life in the field. Leaves and grit pack into the channel, hold moisture against the copper, and abrade and corrode it from the top side. Keeping valleys clear is half of why a slate roof needs an occasional look, and a valley that has gone thin and green-black in the wear track is one of the first things to renew when you bring an old roof back. Confirm the valley metal, gauge, and width against the manufacturer and the design rain load rather than copying the last roof.

Hips and ridges

Hips and ridges are where two slopes meet and the field slates run out, so they get their own slates and their own copper. The two common ridge and hip details are the saddle and the mitered.

The saddle method, the most common on ridges, caps the joint with cap slates that overlap each other along the ridge like the cap shingles on a wood roof, bedded and fastened over copper. Saddle hips do the same down a hip line with paired cap slates extending over the field on each slope. The mitered hip is the cleaner-looking detail: the field slates are cut to meet along the hip line in the same plane, with copper soakers woven in behind to carry the water, so there is no raised cap.

Both work; the choice is appearance, exposure, and what the building already has. What does not change is the metal underneath. Copper flashing or soakers carry the water at the hip and ridge, the cap or the mitered joint sheds it, and the fasteners are the same copper or stainless as the field. Ridge and hip slates and the matching saddle sizes come from the quarry to suit the slate, so order them with the field slate rather than improvising on site.

Walking a slate roof breaks it

Slate cracks underfoot. It is stone, it is brittle, and a careless step in the wrong place breaks a slate that was good for another century. More slate gets destroyed by foot traffic during service work than by weather, and every cracked slate is a future leak and a future repair.

Get the weight off the slate. The right way onto a slate roof is a hook ladder, also called a roof ladder or chicken ladder, that hooks over the ridge and lets you work off the rungs rather than standing on the stone. When you must put a foot on slate, step on the lower middle of a slate where it is fully supported by the course beneath, never on an edge, never on a tail hanging over a course, and never when the roof is wet and slick. Keep your weight low and spread it.

Plan service access into the building, not onto the field. Chimneys, vents, satellite mounts, anything that needs periodic work, should be reachable without crossing acres of slate, because every trip across the field is more breakage. The cheapest slate repair is the slate you never cracked walking to something else.

How do you repair a slate roof?

You repair a slate roof by removing the broken slate, cutting the hidden nails that held it, and securing a matching replacement, all without disturbing the slates around it. The tool that makes it possible is the slate ripper, and the repair is a craft, not a caulk job.

The broken slate's nails are hidden under the course above, so you cannot get a hammer to them. The slate ripper, a long thin steel bar with a hooked, notched end, slides up under the broken slate, hooks a nail shank, and the nail is pulled or its shank sheared by driving the ripper down, striking the shoulder of the tool with a hammer. Work both nails, draw the broken pieces out, and you have a clean slot ready for a new slate.

Then secure the replacement, either with a slate hook driven into the deck or with a nail and a copper bib over the head. What you do not do is face-nail the new slate through its exposed face and smear the hole with sealant. A face nail is a hole straight through the watershed of the roof, and the caulk that hides it fails in a few seasons and leaks for years after, usually right when the rest of the roof is fine. The face-nail-and-caulk repair is the surest sign a slate roof was worked on by someone who did not know slate. Do it with a ripper and a hook or a bib, and the patch lasts as long as the roof.

The slate hook versus the nail-and-bib

Two clean ways exist to hold a replacement slate, and both keep the fastener out of the weather. The slate hook is the modern method and the faster one. The nail-and-bib is the traditional method and the one to reach for where a hook is not appropriate.

A slate hook is a copper or stainless wire fastener with a pointed shank and a hooked end. Drive the point into the deck or between the slates at the joint of the underlying course, set so the crook lands at the tail of the replacement slate, then slide the new slate up over the hook until the hook catches its bottom edge and holds it. No new hole is punched in the slate, nothing relies on a nail you cannot reach, and the hook is sized to last as long as the roof. The small trade-off is a visible hook tab at the slate's tail.

The nail-and-bib method nails the replacement through the slot between the two slates above it with a copper or stainless nail, then covers that nail head with a copper bib slid up under the courses above, commonly around 16 oz copper, several inches wide and long enough to lap the nail by a few inches. The bib sheds water over the fastener so the nail never sees the weather. Cup the bib slightly so friction holds it and it does not creep out over time. Either method, done in the right metal, outlasts a generation. The caulk gun is not on this list.

Matching the replacement slate

A repair only disappears if the new slate matches the old in size, thickness, and color. Slate comes in different lengths, widths, and thicknesses, and a replacement that is the wrong size throws off the headlap and the coursing, while one that is the wrong thickness sits proud or low and cracks or leaks at the laps.

Color is the visible part and the part owners notice. New slate of the same type weathers in over a few years, so a fresh slate often reads slightly off at first and settles toward its neighbors with time. The better matches come from salvaged slate of the same quarry and vintage, which is why a careful slater saves sound slates pulled off a tear-off, and why a building with a distinctive slate is worth keeping a stock of spares for. Match the source and the grade, not the color alone, because a soft slate dropped into a hard-slate roof fails on its own schedule.

Measure the existing slate before you order. Length, width, thickness, the exposure already on the roof, and the hole position all have to line up, or the repair fights the field instead of joining it.

Cutting and holing slate

Slate is cut and holed by hand with simple tools, and the technique is part of why slate work is a trade. A slate cutter, a guillotine-style tool, scores and shears the slate to size and leaves a beveled, chipped edge on the face that looks right next to the existing roof. A power saw leaves a clean machine edge that reads as a repair from the ground, so the hand cutter is the field choice for visible work.

Cut from the back of the slate so the bevel ends up on the underside of the face edge, the way a quarried slate is finished. To hole a slate, punch it rather than drill it, working from the back with the punch on the cutter or a hand punch over a stake, so the punch raises a countersink on the face. That countersink seats the nail head flush, which is exactly the depth the nailing rule asks for.

These are skills you build by doing, and they separate a slate repair that vanishes into the roof from one that announces itself. The tooling is cheap. The hand is what takes time.

Is an old slate roof worth saving?

Assess an old slate roof by separating the slate from everything else holding it up. The decision to restore or replace turns on one question: is the slate itself still sound, or is it the flashings and the fasteners that have failed? Those are very different roofs that look identical from the driveway.

Test the slate. Tap it and listen, a hard sound means sound slate and a dull thud means a slate going soft, and look for delamination, flaking, and slates that crumble at the edges. If the field slate is hard S1 stone with decades left, the roof is almost always worth saving, and the work is renewing the flashings, the valleys, and any failed fasteners while keeping the original slate. If the slate is a soft grade that has reached the end, no amount of new copper saves it and the roof gets replaced.

Nail sickness is the specific failure to name. When the original fasteners corrode, iron and old galvanized nails rust through in roughly 70 to 100 years, slates start sliding off across whole areas at once even though the slate itself is fine. A roof with sound slate but widespread nail sickness is a candidate for refastening or selective rebuilding rather than replacement, and that call is worth getting right because tearing off good slate is throwing away the most expensive part of the roof. When the assessment is close, bring in someone who works slate daily and let the structural condition, not the calendar, decide.

Keeping a slate roof going

A slate roof is low-maintenance, not no-maintenance, and the maintenance is what gets it to its century. The work is small and periodic: inspect it, replace the slates that crack, renew the flashings before they leak, and keep the water moving off the roof.

Inspect from a ladder or with binoculars rather than walking the field, and look for slipped or missing slates, cracked slates, and flashing that has gone thin, green-black, or split in the wear tracks. Replace cracked and missing slates promptly with a ripper-and-hook repair, because one open slot lets water at the underlayment and the deck and turns a small fix into a structural repair. Plan the flashing renewal as a scheduled event around the 60 to 70 year mark, not a reaction to a leak, since the metal reaching the end of its life is the predictable part of a slate roof.

Keep gutters and valleys clear. Debris that dams water on the roof backs it up under slates and holds moisture against the copper, which shortens the flashing's life and forces water where the system never meant it to go. A roof that gets a look every few years and a clean valley outlasts the same slate left alone until something drips inside.

Cost and value over generations

Slate is the most expensive common roof to install and the cheapest to own over its life. Natural slate commonly runs in the range of $15 to $40 or more per square foot installed depending on grade, thickness, and complexity, several times the cost of asphalt and well above synthetic slate.

The arithmetic that justifies it is the life. A slate roof that lasts 100 to 150 years outlives four or five asphalt roofs, so the cost per year of service can land below the cheaper roofs once you count the reroofs you never do. The value is real for the right building: a historic structure where slate is correct, a house meant to stay in a family, a roof where tearing off and redoing the work every 25 years is the expense you are trying to avoid. The cost is paid once and the roof is handed to the next generation, which is the case slate has always made for itself.

Common mistakes

• Galvanized fasteners that rust out long before the slate, taking the slates with them and corroding faster against copper.
• Short-life flashing under a 100-year slate, which builds repeated reflashing into a roof that should have outlived the metal.
• Overdriving the nails, cracking the slate at install or springing it concave so it splits later under load.
• Walking the field and breaking slates instead of working from a hook ladder.
• The wrong slope or a shorted headlap, so water backs up under the courses and finds the fasteners.
• Repairing by face-nailing through the slate and caulking the hole instead of a ripper-and-hook or bib repair.

What to document

Write down the decisions that set the roof's life, because the next person on the roof, decades from now, needs to know what is up there and why. The slate grade, the fastener metal, the flashing metal, and the engineer's load verification are the records that matter most.

Capture them at install and again at every repair and flashing renewal, so the file tracks what the roof actually is rather than what the original spec hoped for. A slate roof outlives the people who built it, and the record is how the craft gets handed forward.

Field checklist

Standards and references

The grade comes from ASTM C406, the standard specification for roofing slate, which sorts slate into S1, S2, and S3 by expected service life using the water absorption, weather resistance, and flexural strength tests. Cite the grade to C406 and confirm the specific slate's rating and the matching grade for your climate with the quarry or manufacturer.

The National Slate Association and the Slate Roofing Contractors Association publish the installation and repair practices the trade works to, and the NRCA Roofing and Waterproofing Manual carries the steep-slope framework that includes slate. Use them for the headlap tables, the slope minimums, the valley and flashing details, and the repair methods, and let the manufacturer's instructions govern where a specific slate or detail differs.

Two hedges control the rest. The weight and the structure are an engineer's call: confirm the dead load with the manufacturer and have a licensed structural engineer verify the framing carries it. The slope, the headlap, the grade, and the fire and wind requirements are set by the adopted code edition and local amendments, so confirm them with the authority having jurisdiction before you build to a number out of habit.

Three rules do not bend, and they are the ones to hold against any shortcut. Fasten with copper or stainless and do not overdrive. Flash with copper to match the slate's life. Repair with a ripper and a hook or bib, not caulk. Hold those three and the roof reaches the century the slate was always good for.

Units and terms

Slate work carries a vocabulary the rest of roofing does not, and the terms below are the ones that decide whether a roof lasts. The weight units run in pounds per square foot and in pounds per square, where a square is 100 sq ft of roof, so an 8 to 15 lb per square foot roof is the same as an 800 to 1,500 lb per square roof.

Natural slate

Roofing shingles split from quarried metamorphic stone, as opposed to molded synthetic or composite slate

Slate grade (S1, S2, S3)

ASTM C406 classification by expected service life: S1 over 75 years, S2 40 to 75, S3 20 to 40

Headlap

The overlap of a slate by the course two above it, giving three thicknesses at every line; 3 in standard

Exposure

The portion of each slate left to the weather, equal to (slate length minus headlap) divided by two

Slate ripper

A long hooked steel bar slid under a broken slate to cut or pull its hidden nails for removal

Slate hook

A copper or stainless hooked fastener driven into the deck to hold a replacement slate without a face nail

Copper bib

A small copper flashing slid under the courses above to shed water over a replacement slate's nail

Nail sickness

Widespread loss of slates when corroded original fasteners fail, even though the slate itself is sound

Related tools

Calculators and readiness checks for this work

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