Ran into a job yesterday where the Sellers disclosure states the roof is Slate, installed in 1916…

The product on the roof is NOT slate, but some type of product that may have asbestos. I was able to break a piece off of a corner, (smaller than a dime)…looks like a pressed hardboard with fibers in it.

Roof is very mossy, dirty and aweful looking, but everything appears to be dry inside.

Any input would be appreciated.



You know, you can get vaccinated for that now!

You report what you observe the roof covering to be. You do not need to, nor should you make any comments about your belief that the listing or disclosure is inaccurate. Your client is smart enough to figure out the discrepancy on their own.

The roof in your photo appears distinctly like a mineral tile (likely asbestos-containing material) roof covering. Mineral tile roofs are magnets for moss, lichen and mildew, which is consistent with your photo. I would not mention breaking off a corner, nor would I do that again. I also would not walk a mineral tile roof as they are very brittle and easy to break.

I agree!:slight_smile:


Thanks for your replys.
Happy Holidays!

I can not really tell but it sorta looks like Transite. “May contain asbestos… only lab testing… bla bla bla”

You have any other pictures?
The image is to distorted to make a material call.


The most common, and strongest, type of slate comes from metamorphic rock, which has been exposed to immense heat and pressure over millions of years. This gives good slate some useful properties:

Slate can be split thinly, reducing the weight of the roof. Some slates distributed by SIG in France are a consistent 2.8mm thick mm 2.8 to 0.110236".

  1. Thick slates should, ideally, be used at the lower roof
  2. Medium thickness slates used in the middle of the roof
  3. Thin slates should be used on the upper roof

1: If the seller declares something, it is his/her decoration they are liable.
Those a crisp endcuts in the valley.

The general term is “fiber-cement”. If it’s old enough to possibly contain asbestos then removal and disposal may be expensive depending on the laws in that jurisdiction and your client should be made aware of that.

Old fiber-cement roofs were long-lived roofing materials, fire resistant and durable.

Generally, any cementitious roofing material that appears to be a magnet for biological growth is a material that is absorbing and holding moisture, which usually means it’s on the downhill side of its lifespan.

Good post Kenton.

I did not think asbestos was used in 1916 for concrete roof slate. Those slates are in excellent condition.
Here is a slate roof from yesterday. Slate roof systems ware.
I would expect to see repairs after 102 years.
I would report what I see and certainly not damage slate to see material.

Old concrete slate.