Slate roofs aren’t repaired in the same way that shingle roofs are, and knowing whether yours needs repair or replacement comes down to some investigation on your roof and some knowledge of what you’ve found. Slate is a very strong and serviceable material, and it was used for roofing long before asphalt shingles were developed. When slate is properly installed it can last longer than a hundred years, but it’s very expensive – around nine hundred dollars for one hundred square feet as opposed to sixty dollars for one hundred square feet for shingles. If you buy a house with a slate roof already installed you’ll want to do some checking as to whether it was installed correctly.
The nails that hold the slate to the roof are there to hang the slate from, much like you would hang a picture on the wall. If they are too tight they can pinch the slate, which needs to expand and contract in the elements. Pinching it can cause it to break. If the nails are too loose they will stick up. That can put stress on the slate that is above it, and those pieces can crack. There is very little margin for error when installing a slate roof, and the same is true for repairing it.
Thankfully, most slate roofs just need to be repaired and don’t need to be replaced. If the slate is soft and flaky, that’s a serious problem. Slate should be dry and brittle. People worry that their slate roof will have to be replaced because a piece or two fell off and cracked. They think that the brittleness of the slate means that something is wrong with it, but it’s actually just the way slate is supposed to be. Repairing a slate roof, though, should really be done by someone who has knowledge of slate and how it needs to be installed.
This will help prevent the slate from breaking or becoming damaged too soon after installation, and it will also help to protect the original slate roof from the new repair that has been done. If a repair isn’t done properly that can put stress on the existing roof and cause the need for more repairs. This is obviously a serious problem, but it’s also one that can be easily avoided by doing a little research and finding the right person to repair your slate roof.