We are going to put our house up for sale. I’d like to evaluate the roofing before hand so I know what we are selling.  The roof is tar & gravel and about seventeen years old. What are some of the signs of age I should be looking for?

The life expectancy of tar & gravel roofs is related to the number of plies originally installed. For instance, three ply roofs (three layers of bitumen impregnated felt) have less life expectancy than a 5 ply system. With this in mind, you can expect to get between fifteen and twenty-five years from these materials. Your roofing is probably in the last third of its life so this is a good time to check for common problems. Here’s what you should be looking for. Bare spots with no gravel should be re-covered with pea gravel. Remember that the gravel reduces the tar-felt exposure to the sun’s UV rays. Often the felts in bare spots will be cracked or “alligatored”.  You can cover these cracks with a coat of roofing bitumen and more gravel but a more permanent solution would be to remove the material and replace it with a felt re-enforced bitumen. This type of repair should be done by a professional tar & gravel roofer.

Also look for tar blisters. Cover them with a coat of bitumen and pea gravel. Look for ridging and buckling of the felts. Little can be done about this except to cover these areas with more gravel top make them less obvious. If water ponds in areas of the roof the felts will deteriorate more rapidly in these areas because the freeze / thaw cycles affect felt life. Note the low spots.  If small in size you can fill them with bitumen and re-gravel or consider re-sloping these areas when the roofing materials are replaced. Other problems such as felt slippage, flashing failures and “fishmouths” can be repaired but should be referred to a qualified tar  & gravel roofing contractor.