I'm going to have to replace some sections of roof sheathing
as part of a re-roof project. What is there now is 1/2" plywood.
I guess it's been OK because it's lasted almost 30 years.
Is 1/2" still OK as far as code goes, etc?
The part that is a problem was due to not being vented correctly,
which I'm going to fix. It's actually one entire section of roof
where that whole section needs to be replaced.

I'm going to get quotes and want to make sure everything is
spec'd. What is typically used now for roof sheathing? Is OSB
ok? is at as good or better than plywood? Oddly looking at Lowes
and HD, it doesn't look like they have sheathing in 1/2". Closest is
15/32.
I guess maybe lumber yards have true 1/2"?

On 2/14/2013 11:58 AM, wrote:
I'm going to have to replace some sections of roof sheathing
as part of a re-roof project. What is there now is 1/2" plywood.
I guess it's been OK because it's lasted almost 30 years.
Is 1/2" still OK as far as code goes, etc?
The part that is a problem was due to not being vented correctly,
which I'm going to fix. It's actually one entire section of roof
where that whole section needs to be replaced.

I'm going to get quotes and want to make sure everything is
spec'd. What is typically used now for roof sheathing? Is OSB
ok? is at as good or better than plywood? Oddly looking at Lowes
and HD, it doesn't look like they have sheathing in 1/2". Closest is
15/32.
I guess maybe lumber yards have true 1/2"?



It's metric out of Canada. 15/32 is the closest inch measurement they
can come up with.

Paul

On Thursday, February 14, 2013 2:58:20 PM UTC-5, wrote:
I'm going to have to replace some sections of roof sheathing as part of a re-roof project. What is there now is 1/2" plywood. I guess it's been OK because it's lasted almost 30 years. Is 1/2" still OK as far as code goes, etc? The part that is a problem was due to not being vented correctly, which I'm going to fix. It's actually one entire section of roof where that whole section needs to be replaced. I'm going to get quotes and want to make sure everything is spec'd. What is typically used now for roof sheathing? Is OSB ok? is at as good or better than plywood? Oddly looking at Lowes and HD, it doesn't look like they have sheathing in 1/2". Closest is 15/32. I guess maybe lumber yards have true 1/2"?

Nobody has true 1/2" any more. OSB is fine. Stronger and cheaper. OSB is used for almost all new construction. Get the little clips to keep it spaced properly. Why'd the original fail? Should have lasted longer than 30 years. Get wet?

On Feb 14, 5:10*pm, jamesgang wrote:
On Thursday, February 14, 2013 2:58:20 PM UTC-5, wrote:
I'm going to have to replace some sections of roof sheathing as part of a re-roof project. What is there now is 1/2" plywood. I guess it's been OK because it's lasted almost 30 years. Is 1/2" still OK as far as code goes, etc? The part that is a problem was due to not being vented correctly, which I'm going to fix. It's actually one entire section of roof where that whole section needs to be replaced. I'm going to get quotes and want to make sure everything is spec'd. What is typically used now for roof sheathing? Is OSB ok? is at as good or better than plywood? Oddly looking at Lowes and HD, it doesn't look like they have sheathing in 1/2". Closest is 15/32. I guess maybe lumber yards have true 1/2"?

Nobody has true 1/2" any more. *OSB is fine. *Stronger and cheaper. *OSB is used for almost all new construction. *Get the little clips to keep it spaced properly. *Why'd the original fail? *Should have lasted longer than 30 years. *Get wet?

It failed on one section that is a cathedral ceiling. The other
two sections have normal attics. And the dumb asses did
not vent the cathedral part. I guess I could have put a
ridge vent in, but I'm not sure it would have made much
difference. I doubt they put baffles in and without them
the insulation is likely blocking the air flow all the way
from top to bottom in each bay. Fortunately it's only
about 900 sq ft.

I did some googling on OSB vs CDX plywood. Seems
they are similar. OSB is less expensive, more water
resistant. But it appears if it does get wet enough, then
it won't return to the same thickness when it dries.
Plywood is easier to get saturated, but when it dries out,
it's more likely to return close to original size.

Looks like it will be 15/32. I doubt that will make any
difference in aligning with any sheets that are still there.
It may not matter. I think in the bad section, probably
going to have to pull it all to so as to put in the missing
baffles for air flow. After tear off, there might be a sheet
or two that needs to be replaced on the rest of the roof,
so the 1/2 vs 15/32 would only be an issue there and I
doubt it matters.

Looking at the cost of various materials, one killer is the
ice barrier that I believe is now required by code for the
lower areas. And I have long eaves, which requires more
of it because as I understand it, the ice barrier needs to
extend up 2 ft beyond where the roof meets the heated
walls. That means I need two passes, each 3ft wide.
That stuff goes for like $79 for a 3ft by 36 ft roll of the
product made by Grace. That's $790 just for that.
The freaking shingles for the whole 43 sq are only $1400.
Maybe there are other products that are less expensive?
Ice damming here hasn't been a problem in 18 years....

On Feb 14, 6:14*pm, "
wrote:
On Feb 14, 5:10*pm, jamesgang wrote:

On Thursday, February 14, 2013 2:58:20 PM UTC-5, wrote:
I'm going to have to replace some sections of roof sheathing as part of a re-roof project. What is there now is 1/2" plywood. I guess it's been OK because it's lasted almost 30 years. Is 1/2" still OK as far as code goes, etc? The part that is a problem was due to not being vented correctly, which I'm going to fix. It's actually one entire section of roof where that whole section needs to be replaced. I'm going to get quotes and want to make sure everything is spec'd. What is typically used now for roof sheathing? Is OSB ok? is at as good or better than plywood? Oddly looking at Lowes and HD, it doesn't look like they have sheathing in 1/2". Closest is 15/32. I guess maybe lumber yards have true 1/2"?

Nobody has true 1/2" any more. *OSB is fine. *Stronger and cheaper. *OSB is used for almost all new construction. *Get the little clips to keep it spaced properly. *Why'd the original fail? *Should have lasted longer than 30 years. *Get wet?

It failed on one section that is a cathedral ceiling. The other
two sections have normal attics. *And the dumb asses did
not vent the cathedral part. *I guess I could have put a
ridge vent in, but I'm not sure it would have made much
difference. *I doubt they put baffles in and without them
the insulation is likely blocking the air flow all the way
from top to bottom in each bay. *Fortunately it's only
about 900 sq ft.

I did some googling on OSB vs CDX *plywood. *Seems
they are similar. *OSB is less expensive, more water
resistant. *But it appears if it does get wet enough, then
it won't return to the same thickness when it dries.
Plywood is easier to get saturated, but when it dries out,
it's more likely to return close to original size.

Looks like it will be 15/32. *I doubt that will make any
difference in aligning with any sheets that are still there.
It may not matter. *I think in the bad section, probably
going to have to pull it all to so as to put in the missing
baffles for air flow. * After tear off, there might be a sheet
or two that needs to be replaced on the rest of the roof,
so the 1/2 vs 15/32 would only be an issue there and I
doubt it matters.

Looking at the cost of various materials, one killer is the
ice barrier that I believe is now required by code for the
lower areas. *And I have long eaves, which requires more
of it because as I understand it, the ice barrier needs to
extend up 2 ft beyond where the roof meets the heated
walls. *That means I need two passes, each 3ft wide.
That stuff goes for like $79 for a 3ft by 36 ft roll of the
product made by Grace. * That's $790 just for that.
The freaking shingles for the whole 43 sq are only $1400.
Maybe there are other products that are less expensive?
Ice damming here hasn't been a problem in 18 years....

Just found out the Owens Corning has an ice barrier
product that is less than half the cost of the Grace one.
A lot more reasonable at $330.

On 2/14/2013 6:14 PM, wrote:

Looking at the cost of various materials, one killer is the
ice barrier that I believe is now required by code for the
lower areas. And I have long eaves, which requires more
of it because as I understand it, the ice barrier needs to
extend up 2 ft beyond where the roof meets the heated
walls. That means I need two passes, each 3ft wide.
That stuff goes for like $79 for a 3ft by 36 ft roll of the
product made by Grace. That's $790 just for that.
The freaking shingles for the whole 43 sq are only $1400.
Maybe there are other products that are less expensive?
Ice damming here hasn't been a problem in 18 years....


I am curious as to why you are paying so much. Nobody I know would ever
pay that high of a price for work like that around here...

On Feb 14, 6:45*pm, Hench wrote:
On 2/14/2013 6:14 PM, wrote:

Looking at the cost of various materials, one killer is the
ice barrier that I believe is now required by code for the
lower areas. *And I have long eaves, which requires more
of it because as I understand it, the ice barrier needs to
extend up 2 ft beyond where the roof meets the heated
walls. *That means I need two passes, each 3ft wide.
That stuff goes for like $79 for a 3ft by 36 ft roll of the
product made by Grace. * That's $790 just for that.
The freaking shingles for the whole 43 sq are only $1400.
Maybe there are other products that are less expensive?
Ice damming here hasn't been a problem in 18 years....

I am curious as to why you are paying so much. *Nobody I know would ever
pay that high of a price for work like that around here...

I haven't paid anything yet. I'm trying to look at the key
issues so when I get quotes I know what I'm getting and
know how much it costs. And I can make sure that the
quotes spec equivalent grade materials.

After making that post, I found that Owens Corning has
a similar ice barrier product that is less than half. And
since I've had no problems in 18 years with no ice dam
product on there now, seems like it;s mighty fine to me.

That brings the material cost to around $2500 for a 4,000
square foot roof. Shingles are $32 a square. Sound
about right?

And for the section that probably needs all new sheating,
I'm going to get it quoted for replacement of that whole
section of roof and on a per sheet basis. That way depending on what
we find when we start taking it off, I won't get hosed.

" wrote:
On Feb 14, 6:14 pm, "
wrote:
On Feb 14, 5:10 pm, jamesgang wrote:

On Thursday, February 14, 2013 2:58:20 PM UTC-5, wrote:
I'm going to have to replace some sections of roof sheathing as part
of a re-roof project. What is there now is 1/2" plywood. I guess it's
been OK because it's lasted almost 30 years. Is 1/2" still OK as far
as code goes, etc? The part that is a problem was due to not being
vented correctly, which I'm going to fix. It's actually one entire
section of roof where that whole section needs to be replaced. I'm
going to get quotes and want to make sure everything is spec'd. What
is typically used now for roof sheathing? Is OSB ok? is at as good or
better than plywood? Oddly looking at Lowes and HD, it doesn't look
like they have sheathing in 1/2". Closest is 15/32. I guess maybe
lumber yards have true 1/2"?

Nobody has true 1/2" any more. OSB is fine. Stronger and cheaper.
OSB is used for almost all new construction. Get the little clips to
keep it spaced properly. Why'd the original fail? Should have lasted
longer than 30 years. Get wet?

It failed on one section that is a cathedral ceiling. The other
two sections have normal attics. And the dumb asses did
not vent the cathedral part. I guess I could have put a
ridge vent in, but I'm not sure it would have made much
difference. I doubt they put baffles in and without them
the insulation is likely blocking the air flow all the way
from top to bottom in each bay. Fortunately it's only
about 900 sq ft.

I did some googling on OSB vs CDX plywood. Seems
they are similar. OSB is less expensive, more water
resistant. But it appears if it does get wet enough, then
it won't return to the same thickness when it dries.
Plywood is easier to get saturated, but when it dries out,
it's more likely to return close to original size.

Looks like it will be 15/32. I doubt that will make any
difference in aligning with any sheets that are still there.
It may not matter. I think in the bad section, probably
going to have to pull it all to so as to put in the missing
baffles for air flow. After tear off, there might be a sheet
or two that needs to be replaced on the rest of the roof,
so the 1/2 vs 15/32 would only be an issue there and I
doubt it matters.

Looking at the cost of various materials, one killer is the
ice barrier that I believe is now required by code for the
lower areas. And I have long eaves, which requires more
of it because as I understand it, the ice barrier needs to
extend up 2 ft beyond where the roof meets the heated
walls. That means I need two passes, each 3ft wide.
That stuff goes for like $79 for a 3ft by 36 ft roll of the
product made by Grace. That's $790 just for that.
The freaking shingles for the whole 43 sq are only $1400.
Maybe there are other products that are less expensive?
Ice damming here hasn't been a problem in 18 years....

Just found out the Owens Corning has an ice barrier
product that is less than half the cost of the Grace one.
A lot more reasonable at $330.

You gotta wonder if the $330 product is a good as the $790 product. I know
that price isn't always an indication of quality, but that's a huge
difference.

I picture a $15K Ford vs a $36K BMW. Same uplift as yours - 2.4X. That
extra $21K isn't going to be just for the name.

Maybe you don't need whatever the extra $460 is going to get you, but is it
really apples to apples with that big of a price difference?

On Thu, 14 Feb 2013 14:10:57 -0800 (PST), jamesgang
wrote:

On Thursday, February 14, 2013 2:58:20 PM UTC-5, wrote:
I'm going to have to replace some sections of roof sheathing as part of a re-roof project. What is there now is 1/2" plywood. I guess it's been OK because it's lasted almost 30 years. Is 1/2" still OK as far as code goes, etc? The part that is a problem was due to not being vented correctly, which I'm going to fix. It's actually one entire section of roof where that whole section needs to be replaced. I'm going to get quotes and want to make sure everything is spec'd. What is typically used now for roof sheathing? Is OSB ok? is at as good or better than plywood? Oddly looking at Lowes and HD, it doesn't look like they have sheathing in 1/2". Closest is 15/32. I guess maybe lumber yards have true 1/2"?

Nobody has true 1/2" any more. OSB is fine. Stronger and cheaper. OSB is used for almost all new construction. Get the little clips to keep it spaced properly. Why'd the original fail? Should have lasted longer than 30 years. Get wet?
The reason OSB is used instead of plywood is price.. Most "half
inch" ply today is closer to 12mm -the international rather than US
standard. 5/8" is better but not used very much. I've seen 3/8 used
but I'd never use it - particularly in OSB here in snow country. (even
though it's been years since we've had a real winter)

Trader4:

If I were you, I would phone around to some of the roofing supply companies and roofing contractors in your area and see what their opinions are on OSB versus plywood and the Dow Corning Ice & Water Shield versus the Grace product. The people that sell and use those products every day would be the most knowledgable as to whether they're much the same thing, or completely different in terms of quality, and where you need to spend the extra money now to avoid spending even more later.

On Feb 14, 7:03*pm, DerbyDad03 wrote:
" wrote:
On Feb 14, 6:14 pm, "
wrote:
On Feb 14, 5:10 pm, jamesgang wrote:

On Thursday, February 14, 2013 2:58:20 PM UTC-5, wrote:
I'm going to have to replace some sections of roof sheathing as part
of a re-roof project. What is there now is 1/2" plywood. I guess it's
been OK because it's lasted almost 30 years. Is 1/2" still OK as far
as code goes, etc? The part that is a problem was due to not being
vented correctly, which I'm going to fix. It's actually one entire
section of roof where that whole section needs to be replaced. I'm
going to get quotes and want to make sure everything is spec'd. What
is typically used now for roof sheathing? Is OSB ok? is at as good or
better than plywood? Oddly looking at Lowes and HD, it doesn't look
like they have sheathing in 1/2". Closest is 15/32. I guess maybe
lumber yards have true 1/2"?

Nobody has true 1/2" any more. *OSB is fine. *Stronger and cheaper.

wrote in message
...
I'm going to have to replace some sections of roof sheathing
as part of a re-roof project. What is there now is 1/2" plywood.
I guess it's been OK because it's lasted almost 30 years.
Is 1/2" still OK as far as code goes, etc?
The part that is a problem was due to not being vented correctly,
which I'm going to fix. It's actually one entire section of roof
where that whole section needs to be replaced.

I'm going to get quotes and want to make sure everything is
spec'd. What is typically used now for roof sheathing? Is OSB
ok? is at as good or better than plywood? Oddly looking at Lowes
and HD, it doesn't look like they have sheathing in 1/2". Closest is
15/32.
I guess maybe lumber yards have true 1/2"?


Since you must go with 1/2", I would go with 1/2" CDX, 4 ply. Don't go
with a 3 ply, even tho you could save a few pennies. And yes, get it at a
real lumber yard.

I have 20+ years in construction, from my younger days. Check out
Certainteed ice/water guard. We always used the sanded, which basically is
a non-slip surface so you can walk on it b/4 the roof covering is down. We
used to start the roll on one end, and be able to roll across the edge
without cutting it into 10' pieces. Most manufacturers recommend to use 10'
pieces because the product is virtually stuck once it is applied. On
Certainteed, you are able to lift it back up if it's not going on straight.
It also has a split back instead of one solid backing, which makes it
easier to apply. I may not explain this very well, but if you applied the
different barriers, you would see the plus side of it. Word of caution, if
using Certainteed, you must apply mechanical fasteners (staples, nails,
etc) on initial installation b/4 walking on it. The adhesive takes a while
to stick, so the fasteners hold it in place so there are no WHOOPS.

On Thu, 14 Feb 2013 14:10:57 -0800 (PST), jamesgang
wrote:

On Thursday, February 14, 2013 2:58:20 PM UTC-5, wrote:
I'm going to have to replace some sections of roof sheathing as part of a re-roof project. What is there now is 1/2" plywood. I guess it's been OK because it's lasted almost 30 years. Is 1/2" still OK as far as code goes, etc? The part that is a problem was due to not being vented correctly, which I'm going to fix. It's actually one entire section of roof where that whole section needs to be replaced. I'm going to get quotes and want to make sure everything is spec'd. What is typically used now for roof sheathing? Is OSB ok? is at as good or better than plywood? Oddly looking at Lowes and HD, it doesn't look like they have sheathing in 1/2". Closest is 15/32. I guess maybe lumber yards have true 1/2"?

Nobody has true 1/2" any more. OSB is fine. Stronger and cheaper. OSB is used for almost all new construction. Get the little clips to keep it spaced properly. Why'd the original fail? Should have lasted longer than 30 years. Get wet?

The major disadvantage of OSB is that if it gets exposed to
significant amounts of water or moisture, the edges expand by up to
15%. . . especially if they are cut edges. This swell will then
telegraph onto the shingles or some flooring. When plywood gets wet,
it expands evenly throughout the panel, dries more quickly and shrinks
down to its original size more rapidly than OSB.

The "little clips" are definitely not used to keep the sheathing
"spaced properly." They are to provide additional support between the
rafters when using minimum code sheathing.

On Feb 15, 11:47*am, "Chomper" wrote:
wrote in message

...

I'm going to have to replace some sections of roof sheathing
as part of a re-roof project. *What is there now is 1/2" plywood.
I guess it's been OK because it's lasted almost 30 years.
Is 1/2" still OK as far as code goes, etc?
The part that is a problem was due to not being vented correctly,
which I'm going to fix. *It's actually one entire section of roof
where that whole section needs to be replaced.

I'm going to get quotes and want to make sure everything is
spec'd. *What is typically used now for roof sheathing? *Is OSB
ok? *is at as good or better than plywood? *Oddly looking at Lowes
and HD, it doesn't look like they have sheathing in 1/2". *Closest is
15/32.
I guess maybe lumber yards have true 1/2"?

Since you must go with 1/2", I would go with 1/2" CDX, 4 ply. *Don't go
with a 3 ply, even tho you could save a few pennies. And yes, get it at a
real lumber yard.

I have 20+ years in construction, from my younger days. *Check out
Certainteed ice/water guard. *We always used the sanded, which basically is
a non-slip surface so you can walk on it b/4 the roof covering is down. *We
used to start the roll on one end, and be able to roll across the edge
without cutting it into 10' pieces. Most manufacturers recommend to use 10'
pieces because the product is virtually stuck once it is applied. *On
Certainteed, you are able to lift it back up if it's not going on straight.

wrote:
On Feb 15, 11:47 am, "Chomper" wrote:
wrote in message

...

I'm going to have to replace some sections of roof sheathing
as part of a re-roof project. What is there now is 1/2" plywood.
I guess it's been OK because it's lasted almost 30 years.
Is 1/2" still OK as far as code goes, etc?
The part that is a problem was due to not being vented correctly,
which I'm going to fix. It's actually one entire section of roof
where that whole section needs to be replaced.

I'm going to get quotes and want to make sure everything is
spec'd. What is typically used now for roof sheathing? Is OSB
ok? is at as good or better than plywood? Oddly looking at Lowes
and HD, it doesn't look like they have sheathing in 1/2". Closest is
15/32.
I guess maybe lumber yards have true 1/2"?

Since you must go with 1/2", I would go with 1/2" CDX, 4 ply. Don't
go with a 3 ply, even tho you could save a few pennies. And yes, get
it at a real lumber yard.

I have 20+ years in construction, from my younger days. Check out
Certainteed ice/water guard. We always used the sanded, which
basically is a non-slip surface so you can walk on it b/4 the roof
covering is down. We used to start the roll on one end, and be able
to roll across the edge without cutting it into 10' pieces. Most
manufacturers recommend to use 10' pieces because the product is
virtually stuck once it is applied. On Certainteed, you are able to
lift it back up if it's not going on straight. It also has a split
back instead of one solid backing, which makes it easier to apply. I
may not explain this very well, but if you applied the different
barriers, you would see the plus side of it. Word of caution, if
using Certainteed, you must apply mechanical fasteners (staples,
nails, etc) on initial installation b/4 walking on it. The adhesive
takes a while to stick, so the fasteners hold it in place so there
are no WHOOPS.

Thanks for the info. And I understand your points. I
watched a video online of one of the ice barrier products
being applied. It had the split backing and I could see
the advantage to getting it positioned and applied.

Looks like the CT product is similar to the Owens Corning
in that it does not appear to be breathable and is priced
similarly. The 1/2" CDX is probably what I'll go with for'
sheathing. My main purpose was to learn enough about
the various issues so that I get the right stuff quoted
and don't wind up with a quote that just says "4x8 sheathing".

What do you think about the breathability issue of the
ice barrier products?

I never heard of a breathable ice barrier, felts yes (and I believe all
felts are). I don't see how an ice/water barrier could be. Thinking about
ice barriers, they have adhesive, there's no way to control the adhesive,
unless it's not sticking thoroughly.

Maybe I'm missing something. But, have been away from construction for
awhile.

On Fri, 15 Feb 2013 12:50:02 -0500, "Chomper"
wrote:



wrote:
On Feb 15, 11:47 am, "Chomper" wrote:
wrote in message

...

I'm going to have to replace some sections of roof sheathing
as part of a re-roof project. What is there now is 1/2" plywood.
I guess it's been OK because it's lasted almost 30 years.
Is 1/2" still OK as far as code goes, etc?
The part that is a problem was due to not being vented correctly,
which I'm going to fix. It's actually one entire section of roof
where that whole section needs to be replaced.

I'm going to get quotes and want to make sure everything is
spec'd. What is typically used now for roof sheathing? Is OSB
ok? is at as good or better than plywood? Oddly looking at Lowes
and HD, it doesn't look like they have sheathing in 1/2". Closest is
15/32.
I guess maybe lumber yards have true 1/2"?

Since you must go with 1/2", I would go with 1/2" CDX, 4 ply. Don't
go with a 3 ply, even tho you could save a few pennies. And yes, get
it at a real lumber yard.

I have 20+ years in construction, from my younger days. Check out
Certainteed ice/water guard. We always used the sanded, which
basically is a non-slip surface so you can walk on it b/4 the roof
covering is down. We used to start the roll on one end, and be able
to roll across the edge without cutting it into 10' pieces. Most
manufacturers recommend to use 10' pieces because the product is
virtually stuck once it is applied. On Certainteed, you are able to
lift it back up if it's not going on straight. It also has a split
back instead of one solid backing, which makes it easier to apply. I
may not explain this very well, but if you applied the different
barriers, you would see the plus side of it. Word of caution, if
using Certainteed, you must apply mechanical fasteners (staples,
nails, etc) on initial installation b/4 walking on it. The adhesive
takes a while to stick, so the fasteners hold it in place so there
are no WHOOPS.

Thanks for the info. And I understand your points. I
watched a video online of one of the ice barrier products
being applied. It had the split backing and I could see
the advantage to getting it positioned and applied.

Looks like the CT product is similar to the Owens Corning
in that it does not appear to be breathable and is priced
similarly. The 1/2" CDX is probably what I'll go with for'
sheathing. My main purpose was to learn enough about
the various issues so that I get the right stuff quoted
and don't wind up with a quote that just says "4x8 sheathing".

What do you think about the breathability issue of the
ice barrier products?

I never heard of a breathable ice barrier, felts yes (and I believe all
felts are). I don't see how an ice/water barrier could be. Thinking about
ice barriers, they have adhesive, there's no way to control the adhesive,
unless it's not sticking thoroughly.

Maybe I'm missing something. But, have been away from construction for
awhile.


For many years thick felt or roll roofing was used "as" an ice-guard.
Sometimes just 2 rows of shingles installed bottom side up under the
finish layer. I know of some areas where 3 feet of galvanized steel
was used along all the drip edges as an ice barrier, with a coat of
tar to seal the nail holes.

Today's self stick polymer products are much better, simpler to
install, readily available, and even reasonably priced. They are
impervious to moisture, so you want to install them on a dry roof.
A friend was doing his own roof - over a period of days, and to be
sure the house stayed dry if it rained before he was done, without
having to tarp, hu used the stick-down blue ice-guard product on the
whole roof. I think it was Henry Blu-skin.