Small stones

[Dunstable Dasher]

I have a flat roof very similar to the one shown in :-

http://s222.photobucket.com/albums/dd36/johnniepk/?action=view&current=mybsack.jpg

on the top of the flat roof there is a covering of small stones/grit, what is the purpose of this ?

 

[breezer]

picture does not show flat roof.

but i believe the smll stones are to reflect sunlight which in turn prolongs the life of the flat roof

 

[noseall]

limestone chippings are there to protect the roof from extremes of sunlight as breezer said. they trap moisture keeping the roof cool as well as shaded.