The message
from Hugo Nebula abuse@localhost contains these words:

AFAIK it is a requirement for all new roofs in Scotland, not so in the
rest of the UK. It may have been used on higher status buildings in
the past where a higher standard of weatherproofing may have been
needed (by the coast, for example), but it was by no means common, and
it is virtually unknown these days (except when the roofer is
Scottish).

My first experience of building work was helping out on a house
reconstruction in Argyll one summer holiday in 1961 or 62. Even then
that roof was boarded first, and by a English Builder from
Stoke-on-Trent of all places.

--
Roger Chapman
Sure as Hell
My next Computer
Won't be a Dell