Roofing contractor Mike Kavanaugh points out shingles that have deteriorated while still under warranty. (CBC)

Roofing shingles are deteriorating well before their guaranteed lifetime warranties, an investigation by CBC-TV's Marketplace has found.

The Marketplace team headed out with roofing contractor Mike Kavanagh to inspect some roofs in Markham, Ont., including one that he installed himself.

“We’re finding at 12 years they’re falling apart,” said Kavanagh. “Just crumbling. This roof is supposed to last 25 years and this basically looks to me to be garbage.”

Canadian shingle companies sell products with warranties of 25, 30 and 40 years, including some with a “lifetime” warranty.

Ten years ago, Larry Bingley forked out $3,000 for a new roof, and not being one to take chances, he opted for more expensive shingles that came with a 25-year warranty.

“I figured 25-year shingles was about the premium, so that would last me a lifetime,” said Bingley.

Markham, Ont., homeowner Larry Bingley had to replace his roofing shingles just 10 years after they were installed. (CBC)

But last year, his roof sprang two leaks.

“I said, what’s this 25-year warranty? And that’s when I found out about the limited section of it,” said Bingley.

Kavanagh, who installed Bingley’s roof, examined it and found the shingles had deteriorated well before their warranty, in fact, nearly 15 years before the warranty was to expire.

“You can see all kinds of granules and larger pieces of shingles in your eavestrough. These ones are starting to dry out very quickly, and they’re not going to last much longer,” said Kavanagh.

Bingley made a warranty claim to the company that sold him the shingles, manufacturing giant IKO.

With 30 production facilities in North America and Europe, IKO agreed to replace the rotten shingles, but Bingley is still out of pocket.

“They offered me 26 bundles of Cambridge 30-year shingles, which has a value of something like $600,” said Bingley.

Bingley said he believes IKO should pay for the shingles and the labour to replace the whole roof, a cost estimated at $6,000.

When contacted by Marketplace about shingles failing too early, IKO said it stood "behind our products and our warranties,’’ and blamed improper installation for early deterioration.