Hi all.
We are taking bids to reroof a low-slope (flat roof) and are looking
at the new modified bitumens( 2 or 2 ply sys). There are lots of
types, but all seem to mention that the base sheet be applied to clean
dry wood decking.I defy anyone to get hot mopped tar off of our
decking. You could likely get the old roll roofing off but the tar it
was set in??!
We are getting many varied ideas as to how to best re-roof it and
wondered what was the norm?

So far we have,
1. Remove it as best as possible and screw down the base sheet, then
the self adhesive 2nd sheet then Cap
2. Leave the roof as is and screw down the base sheet to it. then the
2nd self adhesive sheet then Cap
3. Hot mop OVER the old roof and apply base sheet. then the 2nd self
adhesive sheet then Cap

4. screw down 1" rigid insulation, then use self ashesive base coat,
then the 2nd self adhesive sheet then Cap


Any thoughts and ideas Every roofer to come out has a different idea!

G--

On Jan 27, 7:23 pm, "AustinScoobee" wrote:
Hi all.
We are taking bids to reroof a low-slope (flat roof) and are looking
at the new modified bitumens( 2 or 2 ply sys). There are lots of
types, but all seem to mention that the base sheet be applied to clean
dry wood decking.I defy anyone to get hot mopped tar off of our
decking. You could likely get the old roll roofing off but the tar it
was set in??!
We are getting many varied ideas as to how to best re-roof it and
wondered what was the norm?

So far we have,
1. Remove it as best as possible and screw down the base sheet, then
the self adhesive 2nd sheet then Cap
2. Leave the roof as is and screw down the base sheet to it. then the
2nd self adhesive sheet then Cap
3. Hot mop OVER the old roof and apply base sheet. then the 2nd self
adhesive sheet then Cap

4. screw down 1" rigid insulation, then use self ashesive base coat,
then the 2nd self adhesive sheet then Cap

Any thoughts and ideas Every roofer to come out has a different idea!

G--

Check the various manufacturer's web sites.
If the specifics are not there, contact the tech department.
They want to sell product and they do not want it to fail.
The tech departments are usually very helpful.
That's a good way to sort out the folks who will not support you after
installation.
TB

do you know that hot tar is on the sheathing, or is that just an assumption?
On flat roofs, felt is applied first to sheathing with fasteners, then the
hot tar process is done on top of the felt.
If tar was applied directly to the decking, it was probably done by
amateurs.

Bill


"AustinScoobee" wrote in message
oups.com...
Hi all.
We are taking bids to reroof a low-slope (flat roof) and are looking
at the new modified bitumens( 2 or 2 ply sys). There are lots of
types, but all seem to mention that the base sheet be applied to clean
dry wood decking.I defy anyone to get hot mopped tar off of our
decking. You could likely get the old roll roofing off but the tar it
was set in??!
We are getting many varied ideas as to how to best re-roof it and
wondered what was the norm?

So far we have,
1. Remove it as best as possible and screw down the base sheet, then
the self adhesive 2nd sheet then Cap
2. Leave the roof as is and screw down the base sheet to it. then the
2nd self adhesive sheet then Cap
3. Hot mop OVER the old roof and apply base sheet. then the 2nd self
adhesive sheet then Cap

4. screw down 1" rigid insulation, then use self ashesive base coat,
then the 2nd self adhesive sheet then Cap


Any thoughts and ideas Every roofer to come out has a different idea!

G--

"AustinScoobee" wrote in message
oups.com...
Hi all.
We are taking bids to reroof a low-slope (flat roof) and are looking
at the new modified bitumens( 2 or 2 ply sys). There are lots of
types, but all seem to mention that the base sheet be applied to clean
dry wood decking.I defy anyone to get hot mopped tar off of our
decking. You could likely get the old roll roofing off but the tar it
was set in??!
We are getting many varied ideas as to how to best re-roof it and
wondered what was the norm?

So far we have,
1. Remove it as best as possible and screw down the base sheet, then
the self adhesive 2nd sheet then Cap
2. Leave the roof as is and screw down the base sheet to it. then the
2nd self adhesive sheet then Cap
3. Hot mop OVER the old roof and apply base sheet. then the 2nd self
adhesive sheet then Cap

4. screw down 1" rigid insulation, then use self ashesive base coat,
then the 2nd self adhesive sheet then Cap

Number 4. most closely resembles what I saw them do on the various 30-50
year old gravel-covered hot mop roofs on the monstrosity of a building
complex I work at. (Hey, looking out the window watching them beat looking
at my computer screen.) Rip off or scrape off what they could, apply another
layer of plywood and/or rigid insulation board, put down a layer of some
sort of blue membrane, and then a layer of beige membrane. Mop joints and
flashing with a matching color sealer. No hot-tar buckets in evidence, and
no gravel. Roof looks kinda funny to someone like me used to traditional
methods, but seems to be holding up okay. (This building is 100+ years old,
in this wing, so it has had multiple reroofs and remodels, most badly done,
over the generations.)

aem sends...

Thanks Bill,
No I dont know that it's mopped directly onto the tar. Its just 3 out
of four roofers preferred to go right over the existing rather than
pull it up, mentioning tar and PIA work. Everything on the building so
far has been done to very good standards so I will now assume it was
mopped over the appropriate paper first.

Since most of the roofers want to leave it there, should I suggest
maybe adding 3/8plywood, then 1" insulation, right over it, would it
cause problems?
I will try to reach some manufacturers monday, thr Grace roofing
membranes look really good,
Thanks
G


On Jan 27, 9:36 pm, "bill allemann"
wrote:
do you know that hot tar is on the sheathing, or is that just an assumption?
On flat roofs, felt is applied first to sheathing with fasteners, then the
hot tar process is done on top of the felt.
If tar was applied directly to the decking, it was probably done by
amateurs.

Bill

"AustinScoobee" wrote in ooglegroups.com...



Hi all.
We are taking bids to reroof a low-slope (flat roof) and are looking
at the new modified bitumens( 2 or 2 ply sys). There are lots of
types, but all seem to mention that the base sheet be applied to clean
dry wood decking.I defy anyone to get hot mopped tar off of our
decking. You could likely get the old roll roofing off but the tar it
was set in??!
We are getting many varied ideas as to how to best re-roof it and
wondered what was the norm?

So far we have,
1. Remove it as best as possible and screw down the base sheet, then
the self adhesive 2nd sheet then Cap
2. Leave the roof as is and screw down the base sheet to it. then the
2nd self adhesive sheet then Cap
3. Hot mop OVER the old roof and apply base sheet. then the 2nd self
adhesive sheet then Cap

4. screw down 1" rigid insulation, then use self ashesive base coat,
then the 2nd self adhesive sheet then Cap

Any thoughts and ideas Every roofer to come out has a different idea!

G--- Hide quoted text -- Show quoted text -

If you cap the roof with ply or even pearl board, it is just about
like starting out new. The big difference is the weight of the
existing roof plus the new roof. If your structure can stand the
load, go for it. No one likes tear off and there is a definite
cost in time, money, and clean up/haul off to do the tear off. It
is the right thing to do.

If you don't have 1/4"/ft fall now, you should strongly consider
creating it in this re-roof. Modified bitumen is a great roof,
but you want to make sure water doesn't stand on it.

--
~~~~~~~~~~~~~~~~~~~~
DanG
A live Singing Valentine quartet,
a sophisticated and elegant way to say I LOVE YOU!
(local)
http://www.singingvalentines.com/ (national)


"AustinScoobee" wrote in message
oups.com...
Thanks Bill,
No I dont know that it's mopped directly onto the tar. Its just
3 out
of four roofers preferred to go right over the existing rather
than
pull it up, mentioning tar and PIA work. Everything on the
building so
far has been done to very good standards so I will now assume it
was
mopped over the appropriate paper first.

Since most of the roofers want to leave it there, should I
suggest
maybe adding 3/8plywood, then 1" insulation, right over it,
would it
cause problems?
I will try to reach some manufacturers monday, thr Grace roofing
membranes look really good,
Thanks
G


On Jan 27, 9:36 pm, "bill allemann"

wrote:
do you know that hot tar is on the sheathing, or is that just
an assumption?
On flat roofs, felt is applied first to sheathing with
fasteners, then the
hot tar process is done on top of the felt.
If tar was applied directly to the decking, it was probably
done by
amateurs.

Bill

"AustinScoobee" wrote in
ooglegroups.com...



Hi all.
We are taking bids to reroof a low-slope (flat roof) and are
looking
at the new modified bitumens( 2 or 2 ply sys). There are lots
of
types, but all seem to mention that the base sheet be applied
to clean
dry wood decking.I defy anyone to get hot mopped tar off of
our
decking. You could likely get the old roll roofing off but
the tar it
was set in??!
We are getting many varied ideas as to how to best re-roof it
and
wondered what was the norm?

So far we have,
1. Remove it as best as possible and screw down the base
sheet, then
the self adhesive 2nd sheet then Cap
2. Leave the roof as is and screw down the base sheet to it.
then the
2nd self adhesive sheet then Cap
3. Hot mop OVER the old roof and apply base sheet. then the
2nd self
adhesive sheet then Cap

4. screw down 1" rigid insulation, then use self ashesive
base coat,
then the 2nd self adhesive sheet then Cap

Any thoughts and ideas Every roofer to come out has a
different idea!

G--- Hide quoted text -- Show quoted text -

buffalo ny: some roofs have mandatory tear-off. this makes repairing
of the wood below much easier.
when roofing, first explore additional possibilities [subject to
climate and load and permits and zoning of course] for skylight, deck,
pool slide, adjacent tree house, patio garden, etc. they may modify
your roof selection and be installed before your new roof.
review also, rainwater/snow/ice/gutters/downspouts, deicing cables,
lighting.
lots of other related help:
http://www.buildingscience.com/resources/default.htm

On Jan 27, 7:23 pm, "AustinScoobee" wrote:
Hi all.
We are taking bids to reroof a low-slope (flat roof) and are looking
at the new modified bitumens( 2 or 2 ply sys). There are lots of
types, but all seem to mention that the base sheet be applied to clean
dry wood decking.I defy anyone to get hot mopped tar off of our
decking. You could likely get the old roll roofing off but the tar it
was set in??!
We are getting many varied ideas as to how to best re-roof it and
wondered what was the norm?

So far we have,
1. Remove it as best as possible and screw down the base sheet, then
the self adhesive 2nd sheet then Cap
2. Leave the roof as is and screw down the base sheet to it. then the
2nd self adhesive sheet then Cap
3. Hot mop OVER the old roof and apply base sheet. then the 2nd self
adhesive sheet then Cap

4. screw down 1" rigid insulation, then use self ashesive base coat,
then the 2nd self adhesive sheet then Cap

Any thoughts and ideas Every roofer to come out has a different idea!

G--

do you know that hot tar is on the sheathing, or is that just an assumption?
On flat roofs, felt is applied first to sheathing with fasteners, then the
hot tar process is done on top of the felt.
If tar was applied directly to the decking, it was probably done by
amateurs.

Bill

"AustinScoobee" wrote in message
oups.com...
Hi all.
We are taking bids to reroof a low-slope (flat roof) and are looking
at the new modified bitumens( 2 or 2 ply sys). There are lots of
types, but all seem to mention that the base sheet be applied to clean
dry wood decking.I defy anyone to get hot mopped tar off of our
decking. You could likely get the old roll roofing off but the tar it
was set in??!
We are getting many varied ideas as to how to best re-roof it and
wondered what was the norm?

So far we have,
1. Remove it as best as possible and screw down the base sheet, then
the self adhesive 2nd sheet then Cap
2. Leave the roof as is and screw down the base sheet to it. then the
2nd self adhesive sheet then Cap
3. Hot mop OVER the old roof and apply base sheet. then the 2nd self
adhesive sheet then Cap

4. screw down 1" rigid insulation, then use self ashesive base coat,
then the 2nd self adhesive sheet then Cap


Any thoughts and ideas Every roofer to come out has a different idea!

G--