chris French wrote:

In message , tony green
writes

"Dave" wrote in message
...
Some recent extension work involved slightly changing the run-off point
from a section of flat roofing. Where the new felt at the run-off point
was bonded to the old felt there's now a ridge (about 5mm) so an area of

When I started work in the roofing trade in 1954, all felt roofs had the
outlet standing up about 1"or 25 mm to retain a wet surface,

Which is ok until a leak somewhere occurs...

Keeping the roof wet stops degradation of the felt in the first place.
A wet roof is much better than one that is kept dry, bakes in the sun,
expands, contracts and subsequently cracks. If its is properly done
in the first place, not covered in sharp stones and not regularly
walked on they can easily last 40-50 years.


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