Confusion Over Shingle
Warranty
In the item about shingle warranties with unvented roofs
(Q&A, 1/10), the first sentence clearly states
that GAF’s warranty is still valid when the shingles
are installed over a roof deck insulated with SPF foam. But
later on in the same response, the author says, “since
GAF-Elk does not supply the sprayed-in-place foam insulation,
any damage to our shingles — or any other roof-related
problems attributable either to sprayed-in-place insulation
applied to the roof deck or to a lack of ventilation —
is not covered by the terms of our warranty.”
What kind of double-speak is this? I’ve read the
response over and over again, and I still don’t know
if the company covers the shingles or not.
Rob Knorr
Nordic Construction
Pound Ridge, N.Y.
I wanted to comment on the shingle warranty
Q&A. I love how a manufacturer will, in the
same answer, say, “GAF-Elk’s shingle warranty
is still valid when the shingles are installed over a roof deck
insulated with SPF foam,” and then, “since
GAF-Elk does not supply the sprayed-in-place foam insulation,
any damage to our shingles — or any other roof-related
problems attributable either to sprayed-in-place insulation
applied to the roof deck or to a lack of ventilation —
is not covered by the terms of our warranty.” I read
the response very slowly three times in order to believe what I
was reading; I would appreciate it if JLC would screen
such nonsensical answers.
I’m also unclear what he means by, “The
issue ... is that the insulation can retard or block
moisture-vapor migration through the roof assembly, where it
can then condense in the framing, sheathing, and
insulation.” If the insulation blocks moisture, how
can that moisture then condense? The shingles have nothing to
do with condensation caused by interior vapor drive, so why
mention it?
Mr. Woodring does not allude to another problem, which is that
shingles can curl prematurely — or worse, in hot
climates — on an unvented roof, especially on the
south aspect.
Jim Olson
Viroqua, Wis.
Q&A author Bill Woodring, director of
technical services at GAF Materials, responds:GAF/Elk’s limited shingle warranty covers
manufacturing defects in the shingles and remains valid if the
shingles are installed over a roof deck insulated with SPF. The
warranty does not cover everything that can go wrong in the
roof system.
It’s like a tire warranty: If the front end of
your car is out of alignment and the tire wears out prematurely
and fails because of the misalignment, the tire manufacturer
will not pay for the new tire. However, if there were a
manufacturing defect in the tire that caused the tire to fail,
this would be covered by the manufacturer’s warranty.
Likewise, if an issue develops with the decking or substructure
that causes the roof to leak or the shingles to fail, this
would not be a shingle manufacturing defect and would not be
covered.In answer to Mr. Olson’s concerns,
spray foam insulation will retard moisture-vapor movement to
varying degrees depending on the foam. However, condensation
can occur within the insulation and roof assembly.
That’s why I recommended that the designer or
specifier run dew-point calculations when using spray foam
insulation underneath the roof deck to confirm that the
proposed roof assembly will not have a condensation issue.As for premature curling of shingles, this can occur with
an unvented roof assembly, but historically it’s been
an issue with organic-felt asphalt shingles rather than with
glass-mat asphalt shingles.
Low-Flow Caution
Regarding the story by Leigh Marymor on high-efficiency
toilets (3/10), I agree that less is better, most of the time.
However, low-flow toilets can create a problem when they are
not used often; this can happen, for example, if you have three
people living in a three-bath house. Given intermittent use, if
the drainpipe to the septic system is long, matter dries in the
pipe and clogs things up because there isn’t enough
flow to move the material downstream. Testing to see if the
bowl stays clean or how well matter makes it through the toilet
is only part of the picture.
Jeffrey Price, Esq.
Gainesville, Fla.