Tear Off Old Roof or Not?

You may be faced with the decision of whether to remove your old roof or lay the new one on top of it.

Tearing off the old roof can be messy, and it can add from several hundred to $2,000 to the total cost of your roof job. But it may be worth it.

Mark Vanderslice of Roofing Forensics in Yorba Linda says unequivocally, ‘Yes, tear off the old one. Typically you’re replacing a roof that’s leaking. So it’s common to find problems with the structure--dry rot, termite damage and so forth.”

The homeowner wouldn’t discover these problems until they had become major headaches if he put the new roof over the old, Vanderslice said.

There can be other problems associated with keeping the old roof in place. Catherine Carlisle’s Redondo Beach home was reroofed by the previous owners, who put a new shake roof over the old wood shingle.

But the contractor didn’t extend the new roof beyond the edge of the old. Whenever it rains, water runs in, saturating the bottom wooden layer. This has weakened the original roof and caused decay. “Our roof has monster molds growing along the entire edge and no doubt underneath. We’re just praying the roof doesn’t cave in until we’re ready to remodel,” Carlisle said.

Still other factors, such as the added weight of the old roof and the difficulty in finding any leaks that may come up with the new roof, should also be considered.

According to Vanderslice, “A leak in the new roof is hard to find because no longer does the water run straight down, it meanders through the old roof system. How do you know where to begin? You wind up patching here and there, hit or miss and hope you’ve got it.”

Sometimes local building codes dictate whether you must remove one or more old layers of roofing before installing the new material. The uniform building code allows three layers. But some cities may be more restrictive than that. Glendale adheres to the code-- except in city-designated fire zones. Those homeowners must remove existing wood roofs.

Some cities, such as Culver City, require tearing off. Some manufacturers may require removal of roofing as part of their warranty agreement. Be sure you read the manufacturer’s installation specifications and product warranty. (See story on warranties on Page 8).

Be aware that the tear-off job is a frequent source of problem between homeowner and roofer. Some contractors hire “tear-off crews” who come in and do only that part of the job. In some cases, they neither warn the homeowner about nor take precautions of their own to avoid the huge amount of dirt and debris the job creates. The debris can become a fire hazard when it winds up in places where it is difficult or expensive to remove--like attics or crawl spaces.

Sometimes the contents of garages--from car to cartons of Christmas ornaments are inundated with dirt, wood chips, nails and occasionally even cigarette butts and pop tops, leaving the hapless homeowner enraged and frustrated.

If you do decide on a tear off, talk to your contractor about the potential mess, get it in writing that he is responsible for clean up and haul-off of the debris.

And above all, make sure you get it in writing that the contractor is responsible for tarping your roof in case of rain. Spell out in your contract that he will be liable for any damage that might occur, should it rain while you’re roofless.