Installing chimney flashing in cold weather

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Jakee

Member
Oct 27, 2020
98
New Jersey
I planned on cutting the hole in the roof and installing the flashing tomorrow. I'm in NJ and it's 38º today, supposed to be about 48º tomorrow, 55º day after, so this is my window to do it.
I did a test run today, It's a 7 1/2 pitch roof and I won't have a problem with the hole, but I tried loosening a shingle or two to see how that would go and it's difficult. They're stuck pretty tight. I didn't want to destroy anything so I backed off. I only have about 6" around the sides and top of the flashing.
Do you just muscle through it, or is there a method so as not to scew things up?
Thanks in advance.
My questions will cease at some point.
 
I've never done this but I wonder if you could tent the area using a temporarily tacked down tarp with a space heater under the tarp to warm up the area to 70º? The heater would need a platform to sit on and stay level.
 
I've never done this but I wonder if you could tent the area using a temporarily tacked down tarp with a space heater under the tarp to warm up the area to 70º? The heater would need a platform to sit on and stay level.
Unfortunately that wouldn't be practical, I have a hard enough time not sliding off it. I thought about a heat gun, but I don't have one, nor do I know if it would be a good idea.
 
In most cases at 38 I would be able to work with shingles but if not I always bring a heatgun when doing flashing in cooler weather. It doesn't take long at all to heat them up enough that they are easy to work with
 
In most cases at 38 I would be able to work with shingles but if not I always bring a heatgun when doing flashing in cooler weather. It doesn't take long at all to heat them up enough that they are easy to work with
Thank you. Maybe I'll pick one up today
I was thinking once the hole is cut it might be easier to see exactly what I need to do. I'm just nervous about cutting the hole and then having problems.
 
In most cases at 38 I would be able to work with shingles but if not I always bring a heatgun when doing flashing in cooler weather. It doesn't take long at all to heat them up enough that they are easy to work with
Thanks so much.
I got a heat gun with variable fan and temperature settings. If there are any tips or knowledge you can give I could use it. I haven't used a heat gun on asphalt shingle yet and hate screwing up. Thanks again.
Doug
 
Thanks so much.
I got a heat gun with variable fan and temperature settings. If there are any tips or knowledge you can give I could use it. I haven't used a heat gun on asphalt shingle yet and hate screwing up. Thanks again.
Doug
Just start on medium heat and heat it a little try and try it. If they are still to hard and stuck to much heat it more
 
Be sure and have spare shingles in case you rip one. It's the tar strip that melts and adheres to the shingle below. They used to be pretty wimpy but modern shingles are getting much thicker and stickier tar strips which makes roof repairs like this harder.

Roofing around the flashing is a very difficult thing to do right. Even professionals do it wrong. There are many ways to screw it up.
 
Be sure and have spare shingles in case you rip one. It's the tar strip that melts and adheres to the shingle below. They used to be pretty wimpy but modern shingles are getting much thicker and stickier tar strips which makes roof repairs like this harder.

Roofing around the flashing is a very difficult thing to do right. Even professionals do it wrong. There are many ways to screw it up.
I never found it very difficult at all
 
I never found it very difficult at all
If I use the heat gun where the tar strip is and work it gently with a 4" joint compound blade and prybar when needed, carefully taking out the nails as I go, I should be fine, Right?
My confidence level WAS at 100% until I read Highbeams's post. No offense Highbeam, but I'm nervous about this.
 
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If I use the heat gun where the tar strip is and work it gently with a 4" joint compound blade and prybar when needed, carefully taking out the nails as I go, I should be fine, Right?
My confidence level WAS at 100% until I read Highbeams's post. No offense Highbeam, but I'm nervous about this.
Get a flat pry bar also known as a wonder bar as well. I always use an old slate shingle tool as well but they aren't easy to find.
 
Get a flat pry bar also known as a wonder bar as well. I always use an old slate shingle tool as well but they aren't easy to find.
I only have about 6" on top and 4" or so on the sides to do. If I have to I can bang the nails from the underside to get them started out. My pry bar is flat on one end but I was going to go gentle on it just in case with that 4" blade
 
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I only have about 6" on top and 4" or so on the sides to do. If I have to I can bang the nails from the underside to get them started out. My pry bar is flat on one end but I was going to go gentle on it just in case with that 4" blade
You want one like this.

I have an old one of these that works fantastic.
 
That’s what everybody says.
But it really isn't hard at all. Just remember water runs down hill, and keep all fasteners covered and you really should be fine. And no caulk. If you need caulk you did something wrong.
 
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That's what I have. It's about 30 yrs old and has served me well.
I used to have one of those long shingle rippers like you pictured, but It dissapeared.

Thanks. Over and out for tonight.
Make sure you leave a gap between the cone of the flashing and the shingles ontop. 1/2" to 3/4" should be enough.
 
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I note that shingle companies recommend some spots of roofing tar under the tab edge when doing a repair in cold weather. This is because the built-in tar strips need at least 70º heat to bond well. Do you do this or just use the heat gun to rewarm once all is in place?
 
I note that shingle companies recommend some spots of roofing tar under the tab edge when doing a repair in cold weather. This is because the built-in tar strips need at least 70º heat to bond well. Do you do this or just use the heat gun to rewarm once all is in place?
You shouldn't need it. But a little dab of goop there is fine if needed
 
I have a 22.5/12 pitched A-frame, and regularly have to make shingle repairs due to falling pine branches. The heat gun is definitely your friend. Once your work is done, I would run the heat gun over the tar strips just to give them a little better adhesion. You will eventually get a warm day, but since it's the beginning of winter -- why take a chance. In a pinch, you can always fix a mistake with that "Through The Roof" caulk.

I use a version of this tool when do simple repair jobs. It pries up the shingles, pulls out the nails, and can also pound in nails. It's a great all-in-one roofing tool for small jobs.

[Hearth.com] Installing chimney flashing in cold weather
 
Make sure you leave a gap between the cone of the flashing and the shingles ontop. 1/2" to 3/4" should be enough.
Well the rough part is done, it took all day. The heat gun worked really good, and the flashing is buttoned up for tomorrow. I put a plastic bag over the top even though it's not going to rain. I hooked a rope to the opposite side of the building for something to hang on to. Turned out to be a good idea, 7/12 is slightly more than 45º and felt a little hairy at first but it all went well and I'm in one piece.
I did leave 3/4+ space between the cone base and the shingles on top. Why is that important?

The part that had me stymied for a bit was making sure I placed the top curved edge of the oblong shaped cone the proper distance from the center point of the pipe. I set it up on a table first on a 7/12 pitch, looked down through it, fit the pipe through it as a dry run.
The strange part was that it looked completely different on the roof at the same pitch, and I wanted to make damn sure when I went to mark and cut the hole it would be right.
So thanks again, you've been a big help. I'll take a picture tomorrow.
 
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I have a 22.5/12 pitched A-frame, and regularly have to make shingle repairs due to falling pine branches. The heat gun is definitely your friend. Once your work is done, I would run the heat gun over the tar strips just to give them a little better adhesion. You will eventually get a warm day, but since it's the beginning of winter -- why take a chance. In a pinch, you can always fix a mistake with that "Through The Roof" caulk.

I use a version of this tool when do simple repair jobs. It pries up the shingles, pulls out the nails, and can also pound in nails. It's a great all-in-one roofing tool for small jobs.

View attachment 268972
Your right, the heat gun worked great. That is a nice tool.
 
Well the rough part is done, it took all day. The heat gun worked really good, and the flashing is buttoned up for tomorrow. I put a plastic bag over the top even though it's not going to rain. I hooked a rope to the opposite side of the building for something to hang on to. Turned out to be a good idea, 7/12 is slightly more than 45º and felt a little hairy at first but it all went well and I'm in one piece.
I did leave 3/4+ space between the cone base and the shingles on top. Why is that important?

The part that had me stymied for a bit was making sure I placed the top curved edge of the oblong shaped cone the proper distance from the center point of the pipe. I set it up on a table first on a 7/12 pitch, looked down through it, fit the pipe through it as a dry run.
The strange part was that it looked completely different on the roof at the same pitch, and I wanted to make damn sure when I went to mark and cut the hole it would be right.
So thanks again, you've been a big help. I'll take a picture tomorrow.
12/12 is 45 degrees. Is only about 30. Glad it worked out though