Chimney Breast Damp

[Zebra]

A braver man than I!

Or woman...
Sorry, I'll get off my soap box ...

 

[stuart45]

Thank you for this, it's really interesting as I always assumed they were just thinner slates!

Looking at the pictures, would you have worried over headlap/sidelap on this installation?
I'd love your opinion on what could be improved up there as I will be looking to remedy that area soon.

It's difficult to say without knowing the exact pitch. Generally the lower the pitch, the greater the headlap. I think that the lowest is around 17.5degrees for those tiles, which would require the max headlap of 4 inches. If you increase the headlap too much the weight of the tiles becomes too much for most roofs. You can decrease it to about 3 inches for a steeper pitch. To check it you just need to measure the tiles and take it away from it's length.