On 04/02/2018 11:50, Harry Bloomfield wrote:
Simon T wrote on 03/02/2018 :
http://www.clipsfromthecryptserver1.com/temp/tile1.JPG

Not very much overlap there at all. My roof has three thicknesses of
tile over the entire roof. Loose one tile and it would make absolutely
no difference to weather ingress.

Lucky you spotted it in time to prevent major damage.

Modern roofs don't rely on the tiles for weatherproofing.
The sarking underneath is what makes them weather proof, the tiles are
there to protect the sarking.

You could take all the tiles of my roof and as long as you put them back
in a few weeks/months nothing bad will happen baring a huricane.