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How to cut roof slates

Updated: October 2026

You have slates on a bench, a marked line, and a pair of slate scissors in the bag. The job is a riven edge from the bed, in short bites, without a dry-grinder plume. Mark the underside, support both sides of the cut, snip, then dress. This page is the sequence only. It does not rank the three amazon.co.uk listings. Punch detail sits on [how to punch a hole in slate](/hub/cutting-tools/slate-scissors/sub/slate-scissors-hole-punch). If you still need to choose a tool, start with the [slate scissors](/hub/cutting-tools/slate-scissors) comparison. A qualifying purchase can earn a commission at no extra cost to you.

You have slates on a bench, a marked line, and a pair of slate scissors in the bag. The job is a riven edge from the bed, in short bites, without a dry-grinder plume.

Our top picks

TSF Products TSF SC01G slate cutter

Best overall

TSF Products TSF SC01G slate cutter
8.8/10about £37.95
View offer
Tooltime Tooltime 320 mm slate cutter

Best value

Tooltime Tooltime 320 mm slate cutter
8.0/10about £11.36
View offer
Malco Malco TSNS1 slate turbo shear

Alternative

Malco Malco TSNS1 slate turbo shear
7.4/10about £247.83
View offer
On this page
  1. 1.Mark the bed
  2. 2.Support and short bites
  3. 3.Dress the edge and keep the width
  4. 4.When this sequence stops

Mark the bed

Cut from the back of the slate so the face does not spelch. The bed is the underside as the slate will sit on the roof. Mark the underside, work with the grain where you can see it, and start at the thick end so the thin end is the last bite. Lay the slate face down on a board that does not bounce. Eye protection is not optional: the waste is sharp and it jumps. If the covering might contain asbestos, stop. TSF’s listing claims in-situ use. That does not cancel the Work at Height Regulations 2005. If you can bring the slate to a bench, do that.

Support and short bites

Support both sides of the cut. A cutter that hangs the waste in free air will crush the edge, which is the complaint behind "it chipped rather than cut" on the TSF file. Take short bites. TSF’s stroke is 35 mm, so a 300 mm valley cut is a series of overlaps, not one squeeze. If the frame twists, stop. You are past the listed 6 mm, or the slate is unsupported, or both. Stay inside the listing. TSF states 5 mm. Tooltime states 6 mm. Forcing 8–10 mm stone through either plier ruins the edge and the tool. Do not treat a 28 mm figure on an Edma how-to as capacity; merchant copy for that family prints 7 mm.
TSF Products TSF SC01G slate cutter

Testsieger

TSF Products TSF SC01G slate cutter
8.8/10about £37.95
View offer

Dress the edge and keep the width

A dressed edge is a light tap with a slater’s hammer or the claw, not a second cut. Knock off the small scallops the jaws left, working from the bed again so the face stays clean. If you have to hammer hard, take another short snip rather than beating the stone into shape. SSQ’s remaining-width rules are the ones this page uses: do not cut narrower than half the slate width; leave at least 95 mm at a hip or valley; leave 145 mm at a verge. Mark those limits before the first bite. Once the edge is dressed, the next job is usually two nail holes, punched from the bed.

When this sequence stops

Stop if the slate is thicker than the listing, if the frame twists, or if the edge crushes after you have already supported it. Stop if you are tempted to finish the last awkward valley with a dry grinder on the scaffold. HSE wants hammers and cutters on natural slate and fibre-cement; that argument is on slate cutter vs angle grinder. Call a professional for a high or fragile roof, possible asbestos, or a full re-slate.

Common questions

Why cut from the back of the slate?
So the face does not spelch. The jaws bruise the side they exit. A line on the bed, face down on a board, keeps the visible edge cleaner. If you mark the face because it is easier to see, you will spend the dressing stage hiding a white crush that buyers notice from the garden.
How do I stop the cutter chipping the slate?
Support both sides of the cut, stay inside the listed thickness, and take 35 mm-class bites rather than one long squeeze. TSF reviews that mention chipping usually skip one of those three. Clear debris from the jaws between bites. If the stone is over 5 mm on a TSF, or over 6 mm on a Tooltime, change tool rather than leaning harder.
Do I start at the thick end?
Yes. Work thick to thin, with the grain where you can see it. Starting at the thin end is how a split runs ahead of the jaws. The last bite should be the thinner edge, not the first place the slate can tear.
How often should I clear the jaws?
Whenever waste packs or the hinge grits. On a valley run that can be every few bites. Packed grit turns a shear into a crush, which is the same failure as an unsupported slate. A quick wipe is faster than dressing a ruined edge.
Can I cut on the roof?
Only if you already have a safe place to work at height. TSF’s in-situ bullet does not change the Work at Height Regulations 2005. A bench in the yard is the default. A bungalow roof is still a roof. If you must cut in place, keep the slate supported and keep the method as a hand cutter, not a dry disc.
What if the slate is thicker than 6 mm?
This sequence does not stretch to cover it. Tooltime lists 6 mm; TSF lists 5 mm. Heavies need a slater’s hammer and stake, a merchant plier that actually states 7 mm, or a professional. Forcing the handles is how Tooltime’s frame twists and TSF’s jaws chip.
When is a trowel an acceptable fallback?
When you need to support one side of a single snip and you do not have a second pair of hands or a cutter that holds both sides. It is a fallback, not the plan for a day’s cutting. If you are hanging every waste piece over a trowel, you need a better bench set-up, not a longer session.

Related pages

How to choose a slate cutter

Slate scissors

Best slate cutter UK for porch, bench or long runs

How to punch a hole in slate: gauge and nail metal

Slate cutter vs angle grinder: silica and hand cuts

Sources

Public UK sources and amazon.co.uk listing lines; retrieved 19 October 2026.

  1. HSE, Cutting roofing tiles (retrieved 19 October 2026)
  2. HSE ST5, Sawing slate (retrieved 19 October 2026)
  3. HSE, Roof work (retrieved 19 October 2026)
  4. NHBC 7.2.19, Fixing tiles and slates (retrieved 19 October 2026)
  5. SSQ, Natural slate design and fixing guide (retrieved 19 October 2026)
  6. Wickes, Roughneck slate cutter and hole puncher (retrieved 19 October 2026)
  7. amazon.co.uk, TSF SC01G (retrieved 19 October 2026)
  8. HG Roofing Supplies, TurboShear NS1 (retrieved 19 October 2026)