A slate roof is a beautiful thing. Long-lasting with proper maintenance. While I can’t make you an expert with one Instagram post, here are some things to look for whether you’re an agent vetting a home for a client, or a first-time home buyer.
We look closely, often with binoculars, at every individual slate. We’re looking to see if any of the edges of a slate have a chip or break greater than 25% of any edge—those should be replaced at the next maintenance interval.
The slates are hanging by two nails driven through holes at the top corners and sometimes the nail under a slate will pop up and damage the slate above—popping a hole in it. If it’s just one or two your roofer may opt to seal the holes rather than replacing.
The little metal bracket-shaped snow guards keep a whole sheet of ice/snow from sliding off the roof and landing on your guests’ heads.
Slate can delaminate, too. This occurs when a cleavage plane separates due to normal weathering. Eventually the slate will be too thin.
If it’s a few dozen slates that are in need of replacement figure $30-50 per slate at your annual maintenance interval.
Unfortunately at some point it will be necessary to replace all the slates. Finding and building a relationship with a competent roofer is key to a long and happy relationship with the roof. In Montclair, New Jersey