How to Clean a Slate Roof

What You'll Need
Slate nails
Slate ripper
Flashing: Iron, Copper, Lead, or Steel
Slater's hammer

If, like many modern homeowners, you want long-lasting roofing with a a subdued and natural look, you may opt for a slate roof. In fact, slate shingling has such a reputation for resilience that it has been nicknamed “the hundred year roof.” But if you want your slate roof to last the advertised century, it is important to use to right tools for installation and repair and to understand how to keep it at its best.

Naturally, not all of these specialized tools will be needed for any given repair, but the savvy slate roof owner should be well versed in all of them in order to keep his or her roof at its best.

Step 1 - Testing the Shingles

If your slate appears to be in need of repair, you can likely fix it up yourself without resorting to replacing the entire roof. However, a lot of the “quick fixes” that are appropriate on other types of roofing simply do not work with slate. If cracks appear in a slate shingle, do NOT attempt to patch them with tar. Aside from simply being aesthetically displeasing, these “repairs” can actually conceal further damage to the roof! You are almost certainly better off removing the offending shingle.

To figure out which shingles need replacing, look for any evidently cracked or worn shingles. Tap remaining shingles and take a listen. If you hear a sharp, solid sound, your slate is still healthy. If you hear a heavy thud, it may be time for a replacement.

Step 2 - Replacing the Shingles

If a slate shingle needs to be replaced, use the slate ripper, a 2-foot piece of cast steel, that includes a blade and a hook for the removal of slate nails and broken shingles. Hook the nails and pull them out. Slide the replacement shingle into place.

Punch a hole into shingle from the back. This is necessary because the wider end of the hole has to be facing out for the nail to fit properly into place. Slide the nail into place.

Tap the nail down with hammer. A proper slate hammer is one foot long and made out of a single piece of stainless steel. One end has a sharp point for punching into the slate, while the other has a claw for removing nails. If you cannot obtain a slate hammer, a comparably heavy hammer will work. Slide the flashing under the slate but over the nail head.

Step 3 - Replacing Flashing

While shingles will inevitably have to replaced sometime in the lifetime of a house, their strength means that they may actually outlast the flashing. While this may speak well of the tenacity of your roof, if the flashing fails, you will still have a leak! To replace the flashing, simply follow the steps above, but reattach the same shingle after installing the replacement flashing.

A properly-maintained slate roof can last from 75 to 200 years. With proper annual maintenance, yours will stay with you for a lifetime.