Stack flashing

mattmia2

Is there a better type of stack flashing than this? I have 2 of these that are about 20 years old and the synthetic rubber collar has split on both. one is metal and the collar is replaceable on that, but the other is plastic and I will have to replace the whole flashing anyhow so i would like to use something more durable.

https://www.supplyhouse.com/Oatey-12959-4-No-Caulk-Roof-Flashing-Aluminum

pecmsg

mattmia2 said:

Is there a better type of stack flashing than this? I have 2 of these that are about 20 years old and the synthetic rubber collar has split on both. one is metal and the collar is replaceable on that, but the other is plastic and I will have to replace the whole flashing anyhow so i would like to use something more durable.

https://www.supplyhouse.com/Oatey-12959-4-No-Caulk-Roof-Flashing-Aluminum

Yes

Lead

mattmia2

What kind of lead? the stuff i have seen was kind of a lead ring in the top of a galvanized boot.

JUGHNE

A reason to change flashings when reroofing.

mattmia2

They were new 20 years ago, just apparently picked the wrong ones.

JUGHNE

Pretty hard to lift shingles that are 20 years old, if that is what you have.

You could look at "Dektite" flashings, they have a variety of sizes, trimmable for pipe sizes. You would want one that covered any cut shingles.

I have used them on metal roofs with success.

Lyle {pheloa} Carter

Check kozykollar.com I've installed maybe a dozen and always had good luck. Other than removing the old roof collar and cutting the roof and shingles you won't have to try and bend the shingles to install a new roof collar.

mattmia2

I have several bundles of spares, i think it will be possible as long as i pick a hot day

mattmia2

I don't think whoever designed that kozy kolar understands how a shingle roof works

pecmsg

mattmia2 said:

What kind of lead? the stuff i have seen was kind of a lead ring in the top of a galvanized boot.

mattmia2

i think i saw exactly one of those in like 2" in lowe's once...

does the top roll over inside the stack?

ChrisJ

mattmia2 said:

i think i saw exactly one of those in like 2" in lowe's once...

does the top roll over inside the stack?

From what I recall there needs to be a counter flashing that fits inside the pipe and over that piece. It needs to be able to move up and down with temperature changes and what not.

I have a lead flashing on my 4" stack and I'm going with the one you posted this time around.

mattmia2

If the top edge is just rolled over the top of the pipe and inside the stack, the stack can slip up and down inside.

This is 3" ci and the hub end sticks out above the roof.

heathead

Look at a PermaBoot. Their is another style I like better but can't remember the name. You can use it on your replacement boot. It keeps the boot out of the sun. If needed temporary you could use it over your ripped boot. It slides in pipe so you don't have to mess with shingles.

mattmia2

I thought about making a storm collar out of a strip of copper, possibly to put over the new rubber ring. One is the thermoplastic version and doesn't have a removable rubber ring.

Intplm.

I would use one of these.
You can also get them with a full tube that goes over the edge of the top of the pipe and pean it down and around and inside the stack pipe, rather than the short six-inch tube pictured.

Intplm.

mattmia2 said:

i think i saw exactly one of those in like 2" in lowe's once...

does the top roll over inside the stack?

Yes exactly. The copper one I mentioned above and the lead ones too.

GW

I’ve done hundreds of roof flanges, the image you originally pasted is what I like best. Kinda curious why the originals lost their seal though, I’ve never seen that. 

If you pop the nails (from the attic) up and remove, you can easily remove several shingles to pull the old flange and set the new flange. 

mattmia2

I like the idea of tapping the nails up from below but the decking is 3/4" wood, not plywood. I think a flat bar should get the nails out. It is around ci so maybe it being stretched combined with uv caused the synthetic rubber to degrade and split. i have 2 of them and both have split along with having a lot of checking that i installed with the roof in 2000.

pecmsg

Cut the lead about 1" above the pipe. Using a ball peen hammer peen the extra over the pipe.

ChrisJ

The only thing I feel I can add is whatever flashing you choose, please do not put a shingle on the bottom of it to make it look pretty. Just don't.....

mattmia2

ChrisJ said:

The only thing I feel I can add is whatever flashing you choose, please do not put a shingle on the bottom of it to make it look pretty. Just don't.....

why would i do that. what i do usually try to do is bend the part that brings the water out from under the shingles so it lays flat and glue it down with a couple dots of roof cement so there are no exposed fasteners to maintain.

ChrisJ

mattmia2 said:

ChrisJ said:

The only thing I feel I can add is whatever flashing you choose, please do not put a shingle on the bottom of it to make it look pretty. Just don't.....

why would i do that. what i do usually try to do is bend the part that brings the water out from under the shingles so it lays flat and glue it down with a couple dots of roof cement so there are no exposed fasteners to maintain.

I'm hoping you wouldn't but I've seen an awful lot of people do it.

mattmia2

So this is the 4" collar, what has happened to it after 20 years. The shingles still feel very pliable, I should be able to replace the 3" with lead. The 4" has the aluminum base so i can replace the synthetic rubber collar, the 3" is the thermoplastic version so the collar is welded to the base.



I have not had good luck getting a response from those who purport to sell lead flashings. Any suggestions where I look? The diameter and the height are both a little nonstandard, it has a bead at the to that makes it wider than standard 3" ci.

Larry Weingarten

Hi, Could you put a storm collar on it? https://www.supplyhouse.com/sh/control/search/~SEARCH_STRING=storm collar I see a range of styles.

Yours, Larry

mattmia2

I had considered making a storm collar out of copper but it was getting as complicated and expensive as just replacing it with lead and since the shingles are still pliable, the roof is 8 in 12 and these stacks are the only penetrations, I would like to replace it with something that will last the additional 15-20 years that the shingles will.

JUGHNE

We had a hail storm and our 7 year old roof is considered totaled.

One of the two flashing rubber boots had deteriorated from simply sunlight and maybe a hailstone.

I think I will go back with the Al flashing but put a storm collar just above the neoprene collar to shade it from the sunlight.

For your case the raintite flashings that Larry pointed to above might be the simplest solution.

When we built new I used 3" Sch 80, sunlight resistant, electrical PVC conduit for the roof penetrations.

Both the "Stormchaser" roofers and the insurance were quick to condemn the shingles and gutters. To me it looked like it still had 5-10 years left.

But within 3 days they mailed a check for over $20K to replace....as they did 7 years ago.
You know they are going to get that back out of you in the future.