“Pyrite Free” Slates rusting…

 

4.Severe rust causing breakages within the stone resulting in the roof needing to be replaced(Image 4)

Here is a clear example of slates installed containing “invisible” pyrites.

Within a few months after being installed, the slates started to leach and brown the roof.

You can see that only a certain area of the roof had been affected – luckily the rest of the roof remained intact and the offending slates were removed and replaced.