On 12/03/2015 16:57, Eskimo Will wrote:
That's what mine are. Slates nailed onto 6" wide x 1" thick boards (no
felt). Built in 1915 with a rather steep pitched roof so snow falls off
easily!

My house was built in 1996 and the tiles are terracotta, very thick,
heavy and interlocking. The ends of the roof have stainless steel clamps
to prevent the wind getting 'under-neath' the tiles.

I was told that the roof has this construction because the house is
built near the sea and the needs to withstand higher wind speeds than
would be experienced inland.

It also has vapour barriers and dry-lined walls to minimise damp. It
works well as we have no damp/mold at all despite the rather humid
climate here.

--
Nick Gardner
Otter Valley, Devon
20 m amsl
http://www.ottervalley.co.uk