Slate Roof Maintenance Guide

A slate roof.

Although a slate roof is initially quite costly, it will often last for a lifetime and beyond. In order to maintain your investment and make sure it lasts, a slate roof will need regular maintenance. This can be carried out cheaply and it’s work you can comfortably undertake yourself.

Regular Checks

At least once a year, you will need to carry out an inspection of your slate roof. Do this in the fall so your roof will be effectively maintained for winter. It’s important not to introduce too much foot traffic on your roof and, when you do, a ladder safely hooked onto the roof edge is the best way to carry out a full and detailed inspection as this will help to spread your weight. If it’s absolutely necessary to walk on the slates, walk on the middle of the slate and use soft-soled shoes. Wear a safety harness at all times when working at height.

Maintenance Checking Points

You should check the roof from the attic before climbing up to expect the outside areas. This is beneficial as you’ll be able to see the inside layers of the roof clearly. Take a flashlight and check for water stains on the roof timbers, especially after a long period of rain. If the tiles have water stains, check for any hairline cracks.

You can also do a fair amount of checking at ground level. You can spot a sloped slate roof tile more easily from the ground. If the tiles look to have a powdery surface, this means the tile is deteriorating and you’ll need to replace it. This problem is known as delamination. You can also check for gaps in the mortar joints along the ridge line. If there are any obvious cracks or splits, you’ll need to replace the mortar.


You will need to take care of leaks as soon as you notice them before the problem becomes too bad. Don’t automatically assume it’s the slate roof that’s at fault. It could be the flashing so you will need to check that as well. The flashing and the guttering are actually the weakest points of a slate roof so look at them first.

You also need to check the sheathing under the slates when you’re fixing leaks. If you need to replace sheathing, don’t use plywood or pressure-treated materials. Be sure to replace cracked and broken tiles immediately to avoid damage in your attic.


When you check the roof before winter, make sure you remove all of the debris and foreign matter from the roof. If you don’t, this can cause ice to form on your slate roof and crack the tiles. Ice dams can also form when ice melts and refreezes further down the roof and thus prevents natural run-off. To stop this, especially if you live in a very cold climate, a heating cable along the gutter and eaves can help eliminate the problem.

However, you should never use a hammer to break up the ice of the slate roof. The slate will be brittle with the cold and there’s a very good chance you’ll crack or split it accidentally.

Emergency Repairs

If a slate roof tile needs to be replaced but you can’t do the work immediately, you can temporarily weatherproof the tile. However, you should undertake replacement as soon as possible to help avoid any further possible damage.