I've been told that the first membrane sheets that came out for
Ice/Water had a smooth top side (10 to 15 years ago). That's why
you're seeing smooth membranes now in re-roofing jobs because your
seeing these original membrane sheets.

The membranes now are coated (sanded, granular) and I think it's
because roofers were slipping on the smooth membranes so the granules
make it non-slip. These have been available for maybe 10 years now
and the odd job is coming across these membranes.

I don't buy the argument that the granules are there to be able to
un-roll it (the peel-away backing will prevent it sticking while
rolled up). In theory, the granules serve NO purpose to help the
membrane shed water and actually make it hard for the shingles to bond
to the membrane when the granules are in the way of making a good
bond.

It is said that the asphalt (in the membrane) softens when heated and
migrates around the granules and adheres to the underside of the
shingles. Why go through all that hassle? Seems the granules are
more trouble than they're worth if you need this heating/asphalt
migration thing to happen.

So basically the use of a granular-top-coated peel-and-stick IS a pain
in the butt when it comes to re-roofing and that you can't tear off
old shingles WITHOUT ripping the membrane to hell (yes?) and even more
- that you can expect to destroy or pull up the wood decking. Seems
like a VERY high price to pay - and I'm not sure what the benefit is
(to using THAT kind of membrane).

If I understand this correctly:

If you put on a granular-top-coated peel-and-stick membrane now, then
in 15 or 20 years (when you need to re-roof) that:

(1) the shinges won't release easily from the membrane (because the
membrane NEEDS an asphalt layer to flow through the granules and bond
to the underside of the shingles!)

(2) the membrane won't release easily from the deck

(3) you've essentially got a sandwitch of shingles/membrane/deck that
can't be separated without lots of effort and destruction of the
surface of the wood deck so much so that it becomes more cost
effective to rip the plywood deck off and replace.

Have I got that right?

If so, then the solution is

(a) use a membrane with a smooth top surface with no asphalt layer to
become permanently bonded to the shingles (does anyone make such a
membrane ?)

(b) use a membrane (with a granular top layer or not) but without a
peel-and-stick bottom side (so that you can rip it off later without
messing up the wood deck). Again, does anyone make a NON
peel-and-stick membrane? (seems not).

(c) use a peel-and-stick membrane BUT leave the release sheet on.
Unroll the membrane and nail it down. Then in 10 or 15 years it will
come off easily.

I'm thinking that accidents, law suits, and product liability issues
have played a LARGE role in the design of the currently-available
ice/water membranes.

Think about it - peel-and-stick underside, granular coated top side -
both serve basically ONE purpose - to prevent the roofer from sliping
and falling off the roof. Neither the adhesive underside or the
granular coated top side help AT ALL in helping the membrane perform
it's function of preventing water that gets under the shingles from
making contact with the wood deck.

However, both the peel-and-stick bottom side and
granular/asphalt-coated top side are a MAJOR pain when it comes to
re-roofing.

Comments?