Fair replacement for old John-Mansville Asbestos Slate


Old timers help!
Have Slate tile roof Made by Johns-Mansville 107 years ago and was still in good condition until recently hit by windstorm and tree fell on roof. Insurance company only wants to replace with 25 year roof as per Xactimate. I can not find anything comparable with even a 75 year warranty that is Slate fibered cement that is similar in like , kind and quality that is made today. Do any of you pros know of such a product ? Stuff made today develops effervescence shortly after installation also. Because it has asbestos they do not want to pay for new slate roof.


First things first, Johns-Manville has NEVER quarried slate. The product you are inquiring about is a slate “looking” transite asbestos shingle with a very long lifespan.

What “new products” develope efflorescence? (its not effervescence…that’s soda water bubbles) Cement-based products develop efflorescence.

That said, you will have a problem finding something that has a 75 year material warranty. Even real slate and clay tiles carry only a 50 year warranty.

The insurance carrier should be on the hook for replacing the roof “as is” unless the product is no longer manufactured. This is the pickle you’re in.

Now you need to find a similar slate “looking” product with individual pieces, as opposed to +/- 36" wide asphalt composition shingles.

Your best bet will be a Davinci product and then down the list will be the Carlisle “Eco” product line and then CertainTeed’s Symphony slate. Or, you could investigate a slate “looking” clay tile but you will quickly run into weight problems. And, of course, you could look into the lightweight extruded concrete tile products made by Boral and made specifically for re-roofing houses that do not have the framing elements to support a +1100 lbs. per square dead load. Those products are made in California and shipping them across the country will quickly get expensive, should your project be on the east side.

Last, you could bid a a super high-end shingle like CT Grand Manor or GAF Camelot.

Good luck


First, if it has asbestos content, you need to get a 3rd party Hazmat certified subcontractor to handle the removal and disposal of the asbestos. Very expensive but would be covered by the insurance.

We had something similar last year, i.e., a fiber cement composite with asbestos content. They wanted to replace with cement, then moved to a synthetic composite. We eventually got them to pay enough to install Brava Slate and make a tidy profit.