On 13/03/2016 18:23, pamela wrote:
On 17:18 13 Mar 2016, Mr Macaw wrote:

My neighbour had his roof jetwashed, now he has to replace the
whole thing for £3000.

http://roofcoatingscam.com/is-it-saf...e-wash-a-roof/

"The most common roof tiles in the United Kingdom are
made from concrete and have a sandy/granular finish on
the exposed side of the tile. This part of the tile is
designed to gradually wear off until the tile needs to
be replaced, usually after 80-100 years of normal
weathering."

No wonder the gutters get clogged up with lots of silt.

Why is a concrete roof tile designed to wear away?

When all our coal-fired power stations are gone, where will the building
industry get their raw material from ?. I believe fly-ash from burning
powdered coal is a useful constituent.