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How to Prevent Ice Dams
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Feb 27, 2025
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View Video Transcript
0:00
bit about uh preventing I stams
0:03
um if you are going
0:06
to watch this at a later date meaning
0:09
after it's it's live uh if you have
0:12
questions you can put them in the
0:13
comments uh that's probably the best
0:15
place to do it but you need a YouTube
0:17
account to do that um the one thing that
0:20
I want to also share with you is happy
0:24
to uh answer questions during the uh
0:26
live broadcast if you happen to have
0:29
them uh
0:30
a lot of fun to do uh it's a little
0:33
quirky because I um I do this by myself
0:35
I don't have a producer speaking in my
0:37
ear as to what the question is so you
0:41
know I have to kind of look and read
0:43
what the comment is so anyway we're
0:46
going to talk a little bit about I stams
0:47
and how to prevent them that's really
0:49
the thing uh it's a fitting topic for
0:51
right now
0:53
because it's so cold here where I'm at I
0:57
I'm in cental New Hampshire it's going
0:58
to be8 below zero tonight
1:00
and it was I think it only got up to 17
1:03
degrees today uh I was going to record a
1:06
video outside today uh but got a little
1:09
distracted and Didn't Do It um hey uh
1:13
Jason how you doing can you hear me okay
1:15
are you okay can you hear me I for some
1:17
odd reason I seem to think that I'm not
1:20
there's no audio going out so let me
1:22
know if you can hear me I appreciate
1:24
that um hope you're feeling
1:27
better uh yeah good okay
1:30
earlier today around 11:00 uh where my
1:34
front door is uh gets really nice direct
1:36
sun uh we had two days ago we had a
1:39
storm dropped 8 inches of powder uh here
1:42
in New Hampshire it's not as dry as what
1:44
it is out west but it was really nice
1:45
fluffy snow and the sun it's been very
1:48
sunny um that's very common for storms
1:51
here in New Hampshire we don't once the
1:53
storm hits it it kind of blows and gets
1:56
out of here really quickly uh that's
1:58
because of the Coralis effect at the
2:00
higher latitudes uh it's the same exact
2:03
reason why hurricanes if you've ever
2:05
noticed hurricanes dilly dally around
2:08
down there at the Gulf of America and
2:11
then they then once they start to hit
2:13
the mainland all of a sudden they start
2:15
to move and that's uh that's due to the
2:18
rotational forces of the earth and for
2:21
the same reason a figure skater if you
2:23
have never known that when she brings
2:24
her arms in when she's doing a circle if
2:26
she has her arms out she goes slow but
2:29
she brings her arms in and goes up she
2:31
starts to twirl really fast all right
2:34
same thing with
2:35
storms anyway uh so here it was 17
2:39
degrees today outside and water was
2:42
dripping from the front of my gutters
2:45
all right I've got really nice micromesh
2:47
gutter covers over over the gutters and
2:49
I know what was happening that the sun
2:52
even though it's still winter and still
2:53
bitter cold outside 17° it was melting
2:57
the
2:58
snow and and uh it was coming down the
3:01
roof underneath the snow and then when
3:04
it hits that cold um uh when it hits the
3:08
cold metal uh or any other cold surface
3:12
on the roof it will it typically will
3:14
instantly freeze
3:16
and so here's the here's the thing about
3:20
preventing ice stamps you basically the
3:23
only way to prevent an ice stamp is as
3:26
crazy as it sounds and we do it here in
3:28
New Hampshire all the time is you got to
3:30
get the snow off the roof all right
3:32
there's all kinds of ways to do it we
3:34
have these very handy snow rakes um
3:37
they're they're on these long aluminum
3:39
poles and you can rake the snow off your
3:42
your roof so you have to
3:44
starve the dam if there's no snow on
3:46
your roof an ice dam can't
3:49
form what people really I think they
3:52
confuse it with is they want to know how
3:54
do I prevent having a leak from an ice
3:56
Stam all right that's a that's a
3:58
probably a better question and the way
4:00
you do that is you these products were
4:04
developed 30 40 years ago uh the the the
4:08
leader of the pack is gray and
4:10
watershield and gray and watershield
4:13
developed this membrane think of it as
4:15
just like a giant Band-Aid is about the
4:18
best way to describe it or a huge like a
4:21
three foot wide 50 foot long piece of
4:24
duct tape all right so um it's a
4:28
rubberized asphalt it's an asphalt
4:30
that's got uh styrene badine styrene in
4:33
it SPS that's a polymer that makes
4:36
asphalt really sticky I
4:38
mean like sticky like fly paper if
4:42
you've ever tried to put grayan water
4:44
shield down on a roof that's warm or
4:46
while the product's warm or hot if you
4:49
as soon as you touch it to whatever you
4:51
can't lift it back up it's like contact
4:54
paper so if you were to cover your
4:57
entire roof the substrate with gryon
5:00
waterers Shield um you're not going to
5:03
get leaks you could have an ice Stam on
5:05
your roof you could have 2 fet of water
5:08
backed up underneath the shingles and
5:10
it's not going to come into the home all
5:12
right it's going to just flow across the
5:14
typ top of the gray s and Water Shield
5:17
so but what you commonly see I I I see
5:20
it all the time I see specifications or
5:24
our houses built that only have a 3ot uh
5:27
strip down at the bottom of the roof or
5:29
or they'll have six feet or they'll just
5:32
put one strip in a valley and the
5:36
trouble is is that ice stams they can
5:39
form anywhere um on on a roof all right
5:43
a grandfather I love these I love the
5:46
comment sometimes yeah I do I I am a
5:48
grandfather okay I've got two grandkids
5:51
all right so anyway um just CU I've got
5:54
old hair doesn't mean I'm I'm that dumb
5:56
all right
5:57
I I know it's not great it's
6:00
all right uh Jason can you tell I'm
6:03
having
6:05
fun it's great to be back live again
6:08
okay so ice dams can happen anywhere on
6:10
a roof um they can happen down at the
6:13
bottom they can happen 5 feet up 10 ft
6:15
up wherever they can happen all over the
6:18
roof all right so what really happens to
6:20
make an ice Stam form think about it the
6:23
water the snow melts for whatever reason
6:25
it could be from Lost heat in the house
6:27
it could be from radiation from the Sun
6:29
whatever it's it's the water starts to
6:32
fall through the
6:34
snow uh it hits the shingles or the
6:37
roofing and then all of a sudden it
6:39
comes out and the temperature of the
6:42
surface is below um 32 all right so then
6:47
boom it just starts to flash freeze it's
6:49
super chilled water doesn't take long to
6:52
freeze and if that keeps happening all
6:54
of a sudden you get this ice build up on
6:57
the roof you know you get this ice
6:58
building up like this like this like
6:59
this here's the Tilted roof you know and
7:03
here's the buildup so you get this big
7:05
drough of water back here and it can
7:07
easily flow back up underneath shingles
7:09
remember as shingles um they have a 5 in
7:13
you know they're 5 in exposure so um up
7:16
underneath the shingles um you know only
7:19
takes seven inches to get to the top of
7:22
a shingle and all of a sudden the
7:23
water's going to come right
7:24
through uh if you have any questions um
7:28
feel free to ask them in the comments
7:29
comments I look like the Kentucky no I
7:31
don't have a goatee though come on you I
7:34
don't have the goatee that the colonel
7:36
had Colonel Sanders all right
7:40
um so that's the deal with ice stamps um
7:43
you the best thing is always just to get
7:45
the snow off the roof and and then the
7:49
secondary thing is go ahead if you're
7:52
re-roofing or building a new home and
7:53
there's a threat of you're going to get
7:55
a lot of snow then just put put one of
7:57
these ice and water dam barriers over
7:59
the entire roof I do have people I have
8:02
younger Builders and remodelers who
8:04
bristle at that advice they go oh the
8:08
the um the roof sheathing is not going
8:11
to breathe you know you can't do that
8:13
you know you can't you can't cover the
8:16
the sheathing completely with um uh
8:19
Grayson Water Shield well guess what the
8:23
the regular tar paper oldfashioned tar
8:26
paper is not like a vapor barrier I mean
8:29
I mean I mean it is a vapor barrier it
8:31
it doesn't allow a roof to breathe and
8:33
here you're putting shingles you're
8:36
nailing shingles as tight as possible to
8:38
a a subro if you think there's a lot of
8:40
air moving between your underlayment
8:45
your shingles and the roof sheathing
8:46
you're dreaming all right but keep in
8:49
mind that the underside of the sheathing
8:51
it's breathing all right if the if
8:54
you've if you've installed the
8:55
insulation right in your home and you've
8:57
got a 2-in airspace you know
9:00
between the sheathing and the insulation
9:02
and you've got good
9:03
ventilation there's always air that's
9:05
moving underneath the sheathing and that
9:09
by default is removing any moisture uh
9:13
whatever it's allowing the wood
9:14
sheathing to breathe all right so so uh
9:18
it's just that simple keep in mind on my
9:20
ask the builder website you know if you
9:22
if you just tuned in I'm the ask
9:25
thebuilder guy on online go to
9:27
askthebuilder.com Jason here will tell
9:30
you all about me um and and I have a ton
9:34
of columns there about ice dams all
9:36
right so you can read all about them uh
9:38
you can see all the products uh great
9:41
great photos there and I have a lot of
9:43
videos too I've created a lot of videos
9:44
over the years here at my own home in
9:46
New Hampshire sewing some really
9:48
horrendous ice stams you know so I've
9:51
got lots of information at the website
9:54
askthe builder.com go there and uh have
9:57
have a ball while you're there your mom
9:59
well sign up for the newsletter
10:00
newsletter is a lot of fun um it's kind
10:03
of a quirky newsletter I think you'll
10:05
enjoy
10:06
it um Cara do I have a girlfriend I have
10:10
yes I do Cara my
10:12
wife uh we we celebrated 50 years of of
10:16
being married last year so I do have a
10:19
girlfriend uh and so yes um I hope you
10:22
have a nice boyfriend um 24 millimeter
10:26
wants to know 24 uh how about 35 uh I am
10:30
well I was born and raised in Cincinnati
10:32
uh I live in central New Hampshire right
10:34
now uh Jason and tell the guy who knows
10:38
what he's talking about thank you Jason
10:39
for that plug appreciate it um the um
10:44
the other thing about ice stamps is
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here's what you don't want to do if you
10:47
have one form on your roof uh it's not a
10:51
really great idea to go up there and
10:52
start beating on it with a hammer trying
10:55
to break it up there's a really good
10:57
chance you're going to damage the
10:58
roofing underneath it um there's a
11:01
really good chance you're going to slip
11:02
and fall the ladder might not be set
11:04
right um it's just um it's unfortunate
11:10
what if if you if you don't think your
11:12
roof is protected if you don't think you
11:15
have um the correct underlayment you
11:18
know the ice and watershield type
11:20
products I think the first thing I would
11:22
do is I would reach out to my insurance
11:24
company and find out what what'll happen
11:28
like if you do have
11:29
an ice Stam if you do have a water leak
11:31
inside and you get all kinds of damage
11:34
what is what are they going to cover so
11:37
you know in other words don't lose your
11:39
mind over a roof leak um and it's
11:42
probably if you have anything of value
11:43
in the winter time that's near an
11:45
outside wall where a gutter line is the
11:48
Eve is you might want to move it away in
11:50
case the uh it starts to leak over night
11:53
whatever just use some common sense and
11:56
um that that will help you minimize
11:58
damage to your home
11:59
home um let's see here Brian's got a
12:02
question I have an old house for 1900
12:05
and I add a foot of insulation on top of
12:07
the Old Mex like good idea good idea the
12:09
the thing that I just saw some bad
12:11
information in a little magazine that we
12:13
get here it's a really a promo for um
12:17
home builders and reers in the central
12:19
New Hampshire and it was an article
12:21
about ice stamps and and I just kind of
12:23
shook my head at some of the advice in
12:25
it because the people that were quoted
12:28
in the article the number one thing they
12:30
said was just go ahead and add more
12:32
insulation um sure here's what typically
12:35
happens all right the when when a in in
12:39
some modern houses when the roof passes
12:42
over the outside wall like if this is
12:44
the outside wall of the house and here
12:46
well I'll just do it this way here comes
12:47
the roof and the roof's passing over it
12:50
this area right here um if it's done
12:54
with traditional trusses that we have
12:56
now the heel what we call the heel
12:58
height of the truss of a standard truss
13:01
is only about 4 in so what happens is
13:05
that at that point where the outside
13:08
wall is is um and the drywall is inside
13:12
where they nail the drywall to the truss
13:14
there's only 4 and A2 Ines of space or 5
13:18
Ines of space um between the drywall and
13:23
the underside of your roof sheathing all
13:25
right and then you're supposed to have 2
13:28
in of of um insul airspace so that means
13:32
you might only have three Ines of
13:34
insulation there so what these guys are
13:36
telling it's like oh add a bunch of
13:38
insulation well the problem is it
13:40
doesn't do any good there because you do
13:42
not want to choke off that air space so
13:47
um you know you can add insulation
13:49
farther back in your attic but but
13:53
you're still going to get a a pretty
13:55
decent amount of heat loss going through
13:57
the roof at that spot right where the
13:59
roof crosses over the exterior wall you
14:01
cannot insulate that uh really really
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well I mean unless you ordered trusses
14:07
that have a very high heel height which
14:09
I used to specify or if you common frame
14:12
with 2x 12s all kinds of things so um
14:15
just adding insulation through the old
14:17
attic the whole attic is not going to
14:19
stop I stamps um Ryan says I read some
14:24
vermiculite has asbestos contamination
14:26
from a mine in liby Montana could be um
14:29
could be but who cares seriously all
14:32
right um here I'll get off I'll get off
14:36
on a little tension about asbest for
14:38
just a moment um early in my building
14:41
career which was quite a long time ago
14:44
um I handled lots of asbestos uh we
14:47
would take asbest it would be wrapped
14:49
around duct works of these old gravity
14:51
furnaces really thin uh like almost like
14:55
a Band-Aid um there would be thick 34
14:58
inch thick made like cardboard
15:01
asbes insulation around old furnaces we
15:04
would take all that stuff out all right
15:06
I don't have cancer of the lungs all
15:09
right I didn't wear a mask um I
15:15
um we weren't working with it every day
15:18
all right so I do my now in my family
15:22
and my sister my sister's brother-in my
15:26
let me let me back up my my uh sister's
15:31
husband had a sister and her husband who
15:35
both died of asbestosis he was a union
15:39
plasterer he worked with asbest every
15:43
day he came home from work with asbest
15:46
in his clothes and the wife I'm sure
15:49
picked up the asbes from giving him a
15:52
hug or doing the laundry all right so it
15:55
absolutely is a serious thing if you're
15:57
handling all the time so Brian up in
15:59
your attic as long as you don't go up
16:02
there and you know fluff it up and get
16:05
the vermiculite in the air and cause all
16:07
kinds of dust it's not an issue all
16:09
right it's not an issue period all right
16:12
once again people need to use a little
16:13
bit of Common
16:15
Sense uh okay well that's all I really
16:17
want to talk about about Iams uh once
16:20
again all the information is on the
16:21
website just go to askthebuilder.com uh
16:24
sign up for my newsletter while you're
16:26
there I think you'll enjoy it uh if you
16:28
have have ideas for future live
16:32
broadcasts uh go to the ask Tim Page
16:34
you'll notice at the in the navigation
16:36
there's an ask Tim Page uh just tell me
16:40
that you watched uh the live broadcast
16:42
and uh tell me what you'd like me to
16:44
cover in the next one I'll I'll give it
16:45
a shot uh we're going to have some
16:48
graphics and some more um better things
16:51
to be able to show you um in in in the
16:54
future remember Brian I talked Jason I
16:57
talked about having a whiteboard to draw
16:59
some pictures so anyway thanks for
17:02
watching appreciate it I'm Tim Carter
17:04
ask the Builder and I appreciate you
17:07
watching and um let's see Brian one last
17:10
comment Bri Brian half the house has
17:12
balloon Fram was hard to insulate
17:14
because there was no plot tight plate
17:16
well balloon framing allows you to to
17:18
really go up from the top all the way to
17:20
bottom sometimes it's an advantage the
17:22
only trouble is that you have with
17:24
balloon framing is you don't have any
17:25
installation underneath your uh Windows
17:28
um you know you only get it in the
17:30
places where you where you've got a
17:32
straight shot down all the way from top
17:34
to bottom from the attic down to the
17:36
basement all right uh well thanks very
17:39
much Brian thanks for watching Jason
17:40
thanks for watching everyone else I
17:41
appreciate you being here I'm going to
17:44
start to do more of these live vertical
17:46
lives uh I think that we're can have a
17:48
lot of fun with them and that I'm able
17:50
to share uh the information that uh I've
17:53
accumulated over these decades so thanks
17:55
very much once again go to
17:56
askthebuilder.com sign up for the
17:59
newsletter read everything about ice
18:01
dams and watch all my ice dam videos
18:04
have a wonderful evening
#Roofing