Slate is one of the most traditional building materials, used for roof and floor tiles, among other applications. It doesn’t just look great and provide a premium finish – it offers a wide range of benefits compared to other materials.
As it’s extremely durable, it can actually be relatively cheap (over the long term) compared to other options. Slate tiles are less prone to damage or cracks and don’t need to be replaced as frequently. They won’t fade or degrade either, and slate can also be a low maintenance option. And finally, they can help you improve your home’s energy efficiency rating too.
To enjoy all those benefits, it’s always best to get someone who knows what they’re doing when installing a slate roof or replacing roof tiles. The job demands precision and the knowhow of an expert tradesperson to ensure you get a roof that looks great and stays watertight for years to come.
Cost of slate roofing
The price you’ll pay largely depends on two factors: the quality of the slate you choose and the size of your roof. Locally sourced slates will usually be pricier (but may be better quality) while imported slate will typically be cheaper.
Prices including labour and materials range from:
- Cheap £75–£100 per sqm
- Average: £100–£125 per sqm
- Expensive: £150+ per sqm
How to install a slate roof
As with any specialist building work, it’s always best to call on the experience and craft of a professional. And as slate can be an expensive material, that’s particularly the case here. An expert roofer will usually follow a five-step process.
- Drill the tiles. Unless your tiles are supplied pre-drilled, your roofer will need to make holes in each slate. Your tile manufacturer will usually supply instructions specific to the size and style of the slates.
- Fixing battens. Your roofer will then need to find and mark starting positions for your tiles and battens. That process begins with finding the horizontal centre of the roof. At the bottom of the roof, your pro can then nail a few full slates to calculate the specific batten spacing required for your tiles. When that’s been figured out, the remaining batten strips can be nailed in place at equal intervals across your roof.
- First strip. The first strip of tiles (or starter course) can be nailed down, overhanging the bottom of the roof edge by 1.5–2 inches. This starter strip will usually have an eaves strip (either half tiles, or tiles turned onto their horizontal edge) underneath too, to prevent moisture penetration. When nailing tiles, your roofer should take care not to crack them or underdrive nails, which can cause the next strip to sit unevenly.
- Fixing the remaining tiles. The rest of your roof tiles can then be nailed into position, one row at a time. They should be assembled in a brickwork-like overlapping pattern, with a small expansion and contraction gap of 3 mm between tiles. The vertical overlap (or headlap) between tiles should be at least 3 inches usually.
- Roof apex. The final step is to finish the roof with inverted V-shaped ridge tiles.
How to clean and maintain your slate roof
The most urgent sign that your slate tiles needs attention is a leak. And leaks are typically the result of damaged or cracked roof tiles, problems with lead flashing, obstructions in a roof valley, or debris building up on the tiles or in gutters.
The good news is replacing slate riles, ridge tiles, and lead flashings or valleys is a relatively simple job for a professional roofer. They can quickly remove the defective item and install a replacement with relatively little hassle.
When it comes to cleaning away debris or moss, take care – whether you plan to do this yourself, or instruct a professional to help you.
Cleaning should be limited to removing moss or algae and slate tile flakes. Use heavy rubber gloves and a leaf rake for those tricky-to-access spots. For any stubborn stains, you may need to gently scrub the tiles with a stiff brush and use a cleaning solution.
But avoid the temptation to reach for the pressure washer. It may remove stains or blast away moss, but powerful water jets can damage slates and drive water between gaps, causing leaks.
The qualifications your tradesperson needs
Your roofer won’t necessarily need to hold any qualifications or trade body accreditations to carry out work on your home. But it’s certainly an advantage if they have a City & Guilds award or diploma in roofing.
Above all else, the most important asset to demand from your roofer is experience. And evidence that they’ve used their experience to deliver services to an excellent standard previously.
Planning permission for slate roofing
Installing slate roof tiles won’t require planning permission, but the structure they’re being fixed to may require planning permission before it’s built. Depending on the height and what your property sits near, you may need to consult your local planning office before beginning construction.
Find out what permission you may need at www.planningportal.co.uk.
Insurance your tradesperson needs
Roofing can be precarious work. Think ladders, scaffolding, falling tiles, etc. So, ensure your tradesperson has the necessary cover to protect themselves and your property with public liability insurance.
Questions you should ask your tradesperson
- Have they previously installed slate roofs on a property similar to yours?
- Can they reuse any existing slate tiles (if appropriate)?
- Will they be quoting per square metre, or with a day rate?
- Do they have public liability insurance?
