5 ways to detect old roof failure

Jim Mallery

Do you want to buy a piece of history, living in an old house from the 1950s, the '20s, or even earlier? Don't agree to buy the house of your dreams, only to have the home inspector rain on that dream with a plague of roof problems.

Here are five troubleshooting tips that allow you to play amateur home inspector, so you don't set your heart on what turns out to be damaged goods. Just be prepared -- you'll need to climb into the attic and take a walk on the high side.

The no-brainer signs of roof damage

1. Leaks. Of course, look for the obvious roof problems. Are there water stains on the ceiling? They probably did not get there because junior was playing with his squirt gun. But stains can be painted over; so look, also, for bubbled paint or signs of drywall/plaster repair. Take an especially close look at the always-troublesome skylights, even to the extent of pressing along the corners to see if there is any sponginess.

Then, poke your head into the attic and look for water stains, again paying particular attention to vents and skylights.

Even if you find signs of leaking, the current owner might say that the leak has been fixed. You can find out for sure by renting a moisture meter, probably around $20 for half-a-day, to see if the leaks really have been fixed.

2. Rot. Look for any rotten wood in the eaves or in the attic. Climb up on the roof for a closer inspection. The roofing might be decaying. Or it might be superficially coated with moss, and a little cleaning can leave it looking like new.

3. Chimney. While on the roof, check the chimney. Howard Maxfield, a long-time home inspector in the greater Seattle area, says you should look for loose bricks and mortar falling out. He also advises to look inside the chimney. Make sure it has the flue liner -- required, but not always present.

Deeper roof problems

4. Sagging roof. The old roof could have the slightest dip, not easily perceptible. "Houses built before the '60s didn't have trusses," Maxfield says. "They just had rafters, and one could be broken or sagging."

5. Too many layers. A real problem in old houses, Maxfield says, is multiple layers of roofing. Usually, a roof can support a second layer of composition asphalt shingle laid over the original layer; that saves considerable money in deconstruction and disposal costs. But you shouldn't put any more layers than that on the roof for a couple of reasons: It makes it too heavy, and the nails cannot bite sufficiently into the wood.

"I've seen as many as five layers," Maxfield said. "It costs so much to dispose of the old roofing, some contractors just won't deal with it." But it isn't always obvious how many layers there are, he said, because the roofer puts flashing over the edges, hiding previous layers, and placing new vents on top of the old layers. How, then, can Maxfield tell?

"I go into the attic and look at the vents from the underside," he said. There, you should be able to see the layers of shingles. If the house of your dreams has this problem, you may have to tear off the old layers and install a new roof at considerable expense.

Maxfield says he also sees composition shingles laid over an old wood shake roof, which for various reasons is a horrible idea. Some insurance companies might actually refuse to insure these homes, charge more, or refuse to cover the cost should the roof fail.

The roof is the shield for the whole home, and it probably takes more abuse than any other element of the house. If you're looking to buy an old house, make sure the roof is still viable. Your diligent amateur detective work could save you from having your dreams crushed by the professional inspector -- and a crumbling roof.

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