5 Top Tips to Maintain and Repair Your Slate Roof

Updated October 25, 2021
A house slate roof among a lot of trees
Photo: Ratchat / iStock / Getty Images Plus / Getty Images

Routine maintenance and repairs will keep your slate roof looking like new

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If you’ve moved into a historic home, you may find yourself the proud possessor of a slate roof. And that can be pretty intimidating if you’re used to modern shingle roofs since slate roof maintenance requires different care. However, slate roof maintenance and repair can be quite easy if you know what to do. Learn the best tips for maintaining and repairing your slate.

1. Get an Annual Inspection

If you have a slate roof, by far the most important thing you can do to maintain it is to have an annual inspection by a local slate roofing pro. Though delicate, slate roofs can last a very long time—100 years or more—if taken care of properly.

The first step is to have your roof professionally inspected every spring. This is important for two reasons: it will let you know if any damage occurred throughout the winter, and it will keep you ahead of any major repairs. 

Slate roof maintenance often includes gutter cleaning, inspection for damaged areas, and cleaning of the roof to remove debris, mold, mildew, and moss.

2. Stay Ahead of Slate Repairs

A roofer installing a new slate roof
Photo: TerryJ / E+ / Getty Images

Your annual inspection will alert you to any damage that might have occurred over the course of the year, and especially during the punishing conditions of winter. When you have a slate roof, you can expect that the most common damage will be to the slates themselves.

You are bound to have broken and slipped slates from time to time, especially if you have large trees around your home or there has been a strong storm. A trained slater can repair individual slates easily. Small, chipped corners on slate may look ugly but will not cause a leak. Instead, keep an eye out for missing or badly broken slates. 

These aren’t just unattractive; they can also lead to significant damage to your roof, as well as to interior and exterior walls. A damaged roof, for instance, can lead to water leaks and moisture buildup that can contribute to the growth of dangerous mold and mildew and cause your wood to decay and deteriorate.

Ami Feller, Feller Roofing: “If there is a broken or slipped tile, water can get under the roofing system. If this goes unchecked, eventually the roof repair will grow to include replacing underlayment, battens and decking. By checking it and repairing the roof annually, you save yourself from larger repairs down the road.”

3. Mind the Flashings

In addition to chipped, broken, and missing slates, your slate roof will also be vulnerable at the flashings. These are the metal pieces that can usually be found around chimneys, at the roof ridge, and in the hips and valleys of your roof.

On slate roofs, flashings are usually made of copper or galvanized steel.  If you have copper flashings, you may get off pretty easy when it comes to maintenance since copper flashings generally last around 70 years and are practically maintenance-free.

But if you have an older home, then your copper flashings may already have outlived their expiration date and may need replacement or repair. A good way to assess is by the color. Copper flashings will develop a patina over time, turning from dark brown to rich green.

If your copper flashings are green, that’s a tell-tale sign they’re aging, but still have some time left to them. If the flashings have turned from green to black, though, then that’s a good indication they’re past their prime and may need replacing.

If you have galvanized steel flashing, on the other hand, you’re looking at a life expectancy of between 15 and 20 years. To prevent galvanized flashings from rusting, though, you’re going to need to keep them painted.

4. Take Care of Your Chimney

Chimneys can be a complete headache for a homeowner (and a roofer) if not maintained. You have to consider the chimney itself, the masonry, the flashing, and the cap or flue covers. These different parts all have their own job in keeping water out of your home. 

Chimneys can be very tricky because there are several different causes for a chimney leak. To guard against leaks, a professional will look for the following:

  • Inspect the flashing to make sure it’s still in good condition

  • Check the bricks and joints for any missing mortar

  • Verify that the chimney is properly lined if used to vent a furnace

5. Don’t Forget the Gutters

The final aspect of slate roof maintenance is to keep your gutters and downspouts in good working order.

Both box gutters and hanging gutters each have their own maintenance needs. Box gutters are built into the rafter system of your roof, and from the ground, they look like decorative wood molding around the perimeter of your home. 

Hanging gutters are attached to the eaves of your home using hangers and are visible from the ground.

The trough of the gutters is typically lined either with copper or galvanized steel. As with flashings, if your gutters are galvanized, they will need regular painting. 

Both types of gutters will also need inspection at least once a year to make sure there are no holes and that the solder seams are still intact. This is also a great time to remove debris from the troughs. 

Ami Feller, Feller Roofing: “If you have a lot of debris that builds up in your gutters, you might consider installing a leaf screen or leaf guard. These can generally be installed on existing gutters, and make it so that your gutters require less maintenance.”

Gutters are responsible for getting the water away from your home, so improper maintenance can be as damaging to your home as the failure to repair and replace your slates can be.

For instance, interior leaks in walls and basements and erosion around your home can all be attributed to gutter leaks.

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