On Thu, 12 Aug 2010 20:14:29 -0700 (PDT), Adam Aglionby wrote:

Whats anyones experience of undertile fabrics and the pros and cons?

Had the modern breathable membrane stuff put in when we had our slate
roofs redone a few years back on the basis that the normal sarking
rots eventually and doesn't withstand exposure at all well. ie you
loose a slate and the sarking fails where day light (and water) can
get in between the slates... Along the gutter line our roofers put
18" (maybe 2') wide DPM with the membrane stopping 6" or so short of
the slate edge on top of it. DPM doesn't degrade...

Inside the roof it is dry, there is occasional condensation but it
does dry out no vents as such but it's still pretty drafty up
there... The lofts is much brighter as well, membrane is a light
colour rather than
dark.

--
Cheers
Dave.