CAMBRIDGE -- It’s not hard to tell which slate tiles covering a landmark Cambridge church are brand new.

After hours of steady rainfall on Thursday one section of Central Presbyterian Church’s roof gleamed with a liquid sheen.

But the stone plates protecting another section of roof lacked lustre. Not even a cascade from heaven could make them shine as they would have more than a century ago when they were first installed.

In fact, the friction of repeated rainfalls has worn down the once-stately slate tiles and turned them into thin and flaking remnants from another age.

This past summer workers replaced old tiles covering a 450-square-metre section of roof.

While the worn pieces of slate have served their purpose, they aren’t completely useless.

Darlene Thomson hopes they will help add new life to other sections of church roof.

Thomson, fundraising co-ordinator for the church’s re-roofing project, is turning the old tiles into souvenirs and selling them to raise money for the next phase of the project.

“We’re trying to recycle and reuse,” Thomson said. “People also get to own a piece of history.”

Along with the bowstring bridge spanning the Grand River, the church’s steeple is a landmark for downtown Cambridge.

“It’s part of our architectural landscape,” Thomson said.

Made with the help of a power saw in a parishioner’s basement, the souvenirs include a choice of drink coasters ($10 for a set of four) and cheese platters ($20 each).

The old tiles are so thin and brittle they’re only being made into small coasters. The cheese platters are made from new tiles that were deemed too flawed to install.

They will be available at Heart Strings Fine Giftware & Artful Decor in Cambridge starting Friday Nov. 20. They will also be available at the Cambridge Farmers’ Market on Saturday Nov. 21 and Sat. Nov. 28.

The supply of raw material doesn’t seem to be a problem.

“We have a skid of slate in the basement,” Thomson chuckled.

The entire project, to be completed in four phases over a dozen years, will replace 1,647-square-metres of roof. It’s expected to cost about $1.3 million.

The first phase, completed this past summer, cost slightly more than $235,000. The work was funded by donations from parishioners and grants from the City of Cambridge and the Waterloo Regional Heritage Foundation.

The next phase, replacing tiles over the west side of the sanctuary, is expected to cost $273,000. So far the congregation has donated about $85,000.

Scott Thomson, Darlene Thomson’s husband and a member of the church’s property committee that’s overseeing the re-roofing project, acknowledged that slate tiles are a huge outlay of money.

Covering the roof in asphalt shingles would have cost about $500,000, he said. But in the long term the slate was more cost-effective, he said, because it’s expected to last more than a century compared to a 30-year lifespan for the asphalt shingles.

Scott Thomson said it’s hard to imagine the magnitude of the financial burden on the parishioners who built the church from scratch.

“You have to keep it in perspective,” he said. “All we have to do is put the roof back on.”

In addition to selling slate-tile souvenir coasters and cheese trays, the church is holding a fundraising concert of Handel’s Messiah by Toronto-based musical ensemble Arcady. The concert takes place at 7 p.m. on Saturday, Nov. 28. Central Presbyterian Church is located at 7 Queen’s Square in Cambridge. Tickets cost $20 for adults and $10 for students. Call 519-623-1080.

Anyone wishing to donate to Central Presbyterian Church’s re-roofing project can call the Thomsons at 519-621-0909.