How to Cut Slate Tiles

Slate roof tiles are perhaps the most coveted roofing material for both period and contemporary properties. Slate is a premium material that has been used in roofing for centuries, on everything from cottages and town houses to stately homes and cathedrals. Few materials offer the same combination of character, timeless beauty and exceptional performance. Roofing slates are sourced from quarries across the globe, including Welsh slate here in the UK, as well as slate from Spain or even as far afield as Canada.

However, whilst the incredible durability of slate is one of its primary advantages, it also makes slate roof tiles one of the more challenging roofing materials to work with, especially for novice DIYers. When undertaking a slate roofing project, you may find that you need to cut some of the slate tiles to size. Whilst this process is slightly trickier than cutting clay roof tiles for example, it’s by no means out of reach if you’re equipped with the right tools and know-how.

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Why Choose Slate Roofing?

Slates boast a number of unique advantages over other materials. Slate roof tiles have outstanding longevity, with an expected lifespan of 70 to 100 years or more. Slate is also one of the hardiest roofing materials around, capable of withstanding the very harshest of weather conditions from heat, cold and rain to high winds. What’s more, slate tiles often become far more beautiful with age, as their colour changes and they develop a gorgeous patina, which only adds to their refined character. There are few materials better able to make a home stand out from the crowd.

Another quality of slate roof tiles is their sustainability. Unlike common alternatives such as concrete or clay, slate is a natural material, composed of fine-grained metamorphic rock or volcanic ash deposits. This means that minimal energy is required in their production, and they can be recycled easily at the end of their life. You’re spoilt for choice when buying slate roof tiles here at Roofing Megastore. Our range includes both the iconic Cembrit Glendyne and the Redland Cambrian. Due to their aesthetics, slates are often used to enhance properties in areas of natural beauty.

How to Cut Slate Roof Tiles

Slate tiles can, however, be tricky to cut, and challenging to work with and fit. All hope is not lost however, as with a little patience and the right technique, it’s easy to do with no need for specialist equipment. Below you’ll find out how to cut slate roof tiles with a slate cutter, how to cut slate with power tools and even how to cut slate tiles by hand. As well as teaching you the ins and outs, we’ll also make sure you’re aware of the most common mistakes homeowners make when trying to cut their slate roof tiles.

 

Glendyne Slate

Before You Begin

There are a few things you need to keep in mind before you get started cutting your slate.

Get Everything Together

Be sure to have all the correct materials and equipment you’ll need to start your project. If you’ve calculated how many roof tiles you’ll need beforehand, you should hopefully have ordered the correct amount for your roof.

Safety First

Whether you’re going to cut slate by hand or using power tools, we’d always recommend working either outdoors or in a very well-ventilated area. This is because a large amount of dust can be produced while cutting slate. Furthermore, we’d recommend wearing the correct PPE such as safety googles, safety gloves and a dust mask along with any other protecting clothing you feel you may need to keep the slate dust out of your eyes and prevent yourself from inhaling any.

Mark Your Slate

Whether you’re cutting slate with power tools or hand tools, marking the slate is a very useful first step. This mark will allow you to cut your slate accurately and in a straight line, by acting as a guide. If cutting the slate tiles by hand, we’d recommend marking the underside of the slate. Most people mark slates using a straight edge and a pencil, but if you find the pencil marks too hard to see, you could also use a grease pen, chalk or a bit of masking tape.

Scoring the Slate

The final step before you cut slate is to score a cutting line. This will ensure that you achieve a much cleaner cut by weakening the slate ever so slightly along this line. Using a straight edge such as a steel rule or even a bit of wood, score a line along your slate tile using the sharp end of a chisel. Press down hard enough to create a clear line, but not so hard that you risk splitting or cracking the slate. A tool such as a carbide-tipped pencil will help you to be more accurate than a chisel.

Which is Better for Cutting Slate, Power Tools or by Hand?

It’s perfectly possible to cut slate tiles with power tools, a slate cutter or by hand, and often the best option for you is down to your own experience and which method you feel most comfortable using. Hand tools are easier to use for novices, but it can be more difficult to be as accurate as using power tools. We’d not recommend using power tools to cut slate unless you’re confident however, as it’s far riskier. If you’re at all unsure or uncomfortable as to how to cut slate, then we’d recommend consulting a professional. Whilst this option may cost more, it’s ideal for giving you peace of mind.

Cembrit Slate

How to Cut Slate Tiles by Hand

If you’re going to cut slate roof tiles by hand, there are two common methods. The first uses a hammer and chisel, and the second a pair of slate cutters. Do note however that cutting slate by hand is only recommended for thinner slates up to 4mm thick.

Cutting Slates with a Hammer and Chisel

  1. Using a straight edge and pencil, mark the underside of your slate.
  2. Score your slate by gently driving a chisel along your marked line.
  3. i) Place your chisel within the groove you’ve scored, and gently tap it with your hammer. Go down the line until the slate breaks cleanly into two pieces
    ii) OR, align the scored line with the edge of your work bench and apply firm pressure to the overhanging edge. If the tile has been scored correctly, it should snap cleanly in two.

Cutting Slates with Tile Cutters

If your slate tiles are thicker than 4mm and you’d still like to cut them by hand, we’d recommend investing in a pair of tile cutters or a slate guillotine. These tools have been specially designed to achieve a clean cut on slates and tiles, allowing you to quickly and accurately cut slates. Simply line your cutters up with your scored edge and apply gentle pressure cutting along the line until you’re done. Another advantage of cutting slate by hand this way is minimised risk of breakages.

How to Cut Slate Roof Tiles with Power Tools

There are many power tools you can use to cut slate which we’d recommend you use if your slates are thick or you have a lot of slates to cut. There are three power tools that are typically used to cut slate, which include circular saws, angle grinders and wet saws. As with cutting slate by hand, always wear the correct safety equipment, especially as far more dust will be created when cutting slate with power tools.

Cutting Slate with a Circular Saw

  1. As with other methods of cutting slate, the first step is to mark a line on the underside of your slate using a straight edge and pencil or grease marker.
  2. Score along the slate using a chisel in tandem with a straight edge to ensure a nice consistent line. Be sure to also mark where your line meets the edge of your slate tile.
  3. When cutting slate with a circular saw, use either a diamond-tipped or carbide blade, ideally one that is as thin as possible for maximum accuracy and to avoid damage.
  4. Clamp your slate down onto the platform to keep it secure and ensure you can achieve a clean, professional straight cut.
  5. Place the blade over your marked line, and slowly cut along the line by lowering or turning your circular saw on.
  6. Continue at a pace you’re comfortable with to avoid mistakes and get the best results. Repeat the process until you’ve cut all the slates you need to.

Cutting Slate with an Angle Grinder

  1. Once again, mark out the line you’re going to cut along the underside of your slate using masking tape or a pencil and straight edge.
  2. Carefully score along this line using a chisel and straight edge, being careful to keep your line straight and avoid damaging your slate by pressing to hard.
  3. Ensure that your angle grinder is fully functioning before you begin. Opt for a multi-purpose diamond blade, as this is by far the best option for cutting slate.
  4. Secure your slate tile onto your work bench using a clamp, as this will restrict any movement whilst you work.
  5. Slowly lower the angle grinder down onto the slate, using a careful “up and down” motion along the scored line. This will help to clear dust from the blade as you go, and ensure a smooth, uniform cut. Continue until you’ve completely separated both pieces.

Cutting Slate with a Wet Saw

  1. Using a pencil or grease marker and a straight edge, mark out the line where you’d like to cut along the underside of your roof slate.
  2. Gently press a chisel along this mark to score out your cutting line.
  3. Test your wet saw before you use it, either using a scored line or the measuring tool on the machine.
  4. Turn on the saw, ensuring that water is running through it effectively before you begin.
  5. Pull the blade over the slate, carefully following along your marked line, and slide the saw back before removing your newly cut slate tile.

Final Tips for Cutting Slate

By following the steps above along with your manufacturer’s guidelines, you’ll be able to quickly and easily cut your slate roof tiles. However, it’s important to remember that slates can break easily if you’re not careful. It’s therefore recommended to account for around 5-10% wastage when purchasing slate tiles.

Take a look at our tips below to help you avoid damage and learn how to add a tasteful rivened edge to your slate.

  • Where possible, try to cut along the grain of your slate
  • If cutting diagonally, cut from the thickest part of your slate to the thinnest
  • When cutting slates by hand, look out for slate cutters with a built-in nail puncher
  • To add a rivened edge to your slate, lightly tap along the edges with a claw hammer

Conclusion

As you can now see, there is no single answer to “How to Cut Slate?”. The best way to cut slate for you depends entirely upon your level of experience and confidence in doing DIY. If you’re a beginner, then we’d recommend hand tools to cut your slates to size for a smaller project, but power tools are fantastic for getting the job done quickly on a large number of slates.

No matter which method of cutting slate you choose, as long as you take the time to prepare and approach the task carefully, you’re sure to achieve great results. Plus, once your slate roof has been completed, it’s bound to look brilliant, and last you many decades. Take a look at our full range of slate roof tiles today.