Slate roofs by far are the longest lasting roofing material available. Slate-shingles have been used as a roofing material for hundreds of years and many of those roofs will last 200 to 300 years which is quite an long time and very impressive. Slate last so long because it is a natural stone and stone survives for thousands of years so it would only many sense a roof made from this material would last just as long. Even though slate roofs are very long lasting, damage to individual shingles can and do happen. Damage can happen from falling tree branches, walking on the roof and ice. Slate roofs are not meant to be walked, they don't stand up well to it and this is why, in many instances, slate roofing shingles require replacement.
Slate used for roofing material is made by cutting thin layers from large pieces of slate. Slate roofing shingles vary in size, thickness and color, all of which adds to the charm of these roofs.
When replacing a slate roofing-shingle, consider using a salvaged-shingle which may better fit the color scheme of your roof and may have been mined around the same time as your existing slate-shingles. Whenever possible, bring your old, damaged shingle with you when buying a new shingle so that the thickness, size and color can be better matched.
Use a tool called a slate ripper. A slate ripper is a piece of metal that is inserted under a slate-shingle, has an edge that hooks onto a nail and a raised bottom area that when struck with a hammer will pull the old nail out of the shingle.
Remove the nails from the damaged slate-shingle with the slate ripper.
Remove the damaged slate-shingle.
Buy a new replacement shingle. Carefully measure to get a correct size shingle, unless you are able to cut it down.
Put it in place. Mark the gap between the 2 above the replacement shingle.
At the back end of the replacement shingle, after it is aligned, mark the areas where nail holes need to be punched.
Punch nail holes with a slate hammer. A slate-hammer has a sharp "pick" end.
Place the slate-shingle in place and hammer galvanized nails through the pre-punched holes to secure the shingle in place.
Gently, yet firmly stick a screwdriver under each of the 2 shingles above the replacement to lift them slightly.
Slide a piece of copper flashing under the slate-shingles to cover the new nail holes.
Remove the screw drivers and cut away excess copper flashing.