In article ,
"harryagain" writes:

"Dave Plowman (News)" wrote in message
...
In article ,
harryagain wrote:
Most lead has been replaced with various sorts of plastic these days.
You can buy plastic valley pieces and aluminium soakers for roof work.

Love to know what plastic has anything like the life of lead when exposed
to the elements.

Lead lasts for many decades. Even centuries.
However there is a move to get lead out of the environment.
Causes brain damage.
Could be TNPs problem.
Usually cracks appear in it on corners etc due to work hardening and
vibration with wind. Eventually.

The cracks are mainly due to thermal cycling.
Hence, larger pieces have shorter lives.
You should get at least 70 years from a good installation
using lead strips. (Sheet lead may be less - not sure).
You may need to redress it into brickwork one or two times
during this period if the mortar and/or wedges fail, which
again does happen due to thermal cycling and movement of
the lead.

Noboby knows how long the plastic stuff will last.
It is tested by the BRE.

I've had a GRP valley gutter for almost 30 years. 10 years
ago, I refitted the roof around it, but the plastic itself
was fine and I kept it (just had to add new sand strips for
pointing onto it).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]