Metal Roof Flashing Question..

[draughtdude]

Working away at the tiny house and getting closer to installing ceiling support box. The box and Class A pipe I intend to use are made by Selkirk (supervent). I've actually already bought the ceiling support box. When it comes to flashing on a metal roof, Selkirk doesn't seem to have anything other than a rubber boot kit and I've heard these don't hold up well.

Does anyone know if it would it be possible to use the ICC Excel flashing with the Selkirk pipe?

Thanks,

John

 

[begreen]

It should be ok to use with Selkirk pipe as long as the Selkirk OD is the same as the Excel pipe.

 

[draughtdude]

Well it appears that ICC Excel chimney has an OD of 8" and Supervent is 10". They both claim to achieve the same performance but Excel does it with a 1" wall? Would the Supervent be a better chimney???

 

[Hogwildz]

Wider isn't necessarily better. Also means larger look, larger hole(s) etc.
Depends if you mind seeing a larger pipe or not.
Either will do the job fine.

 

[webby3650]

It works very well. Both excel and super-vent have the same OD. If you have less than a 4 pitch roof, I wouldn't recommend the excel flashing.

 

[webby3650]

You are either looking at triple wall or 8". The 6" super-vent 8" OD.

 

[jeff_t]

From my experience, the Supervent 6" is a wee bit sloppy in the Excel flashing. I used a roof support anyway, so it didn't matter that much. Just goobered a bunch of silicone on it before I put the storm collar on.

I have it on a 3/12 roof, and so far no problems, but it is right off the peak.

 

[begreen]

Well it appears that ICC Excel chimney has an OD of 8" and Supervent is 10". They both claim to achieve the same performance but Excel does it with a 1" wall? Would the Supervent be a better chimney???

Methinks you are reading the specification incorrectly. 6" ID Supervent should be 8" OD. 6" DuraPlus is 10" because it's triple wall pipe.

 

[Oldman47]

Consider this. The flashing really just seals out the rain at the roofing surface, not at the chimney pipe. If it is close it is good enough for rain sealing. For support of the pipe it needs to be pretty close but not perfect. The storm collar and silicone is what makes the pipe not have water running down it. Look at that flashing. It has slots all around it to let the chimney breathe where it penetrates the roof deck. The storm collar covers the slots in the flashing and is what needs to marry up well with the chimney pipe. If you get a good seal from the storm collar and then silicone seal it with high temperature silicone you will not have any roof leaks.

 

[draughtdude]

Begreen, The US spec supervent is 1", but I "think" because Canada mandates the chimney survive three 30 minute chimney fires instead of three 10 minute ones, the Canadian spec is 2" insulation. http://www.selkirkcorp.com/supervent/Product.aspx?id=100 I guess Excel is using higher quality materials to pull off the same spec in a 1" insulation package??

I'm not keen on the EPDM rubber boot so I think I'll switch gears and do Excel all the way, and use their smaller OD chimney and their flashing.

Oldman47, You raise a good point, but I wonder how difficult it would be to modify the smaller hole in the excel flashing for the larger Selkirk pipe... might not be worth it.

 

[draughtdude]

It works very well. Both excel and super-vent have the same OD. If you have less than a 4 pitch roof, I wouldn't recommend the excel flashing.

The roof is 2/12. Maybe the boot is better then?

 

[draughtdude]

Ahh now I understand why in my other thread you guys all thought it was weird that the Selkirk support box was 14". Needs to be for the 10" chimney! Makes sense now!

 

[draughtdude]

I really appreciate all your help, it's helping me narrow down the choices and make the right decisions!

 

[jeff_t]

If that's the case, you can use the flashing for 8".

 

[webby3650]

The roof is 2/12. Maybe the boot is better then?

In this case I would use a boot with a storm collar and a roof brace kit.
The excel flashing is wedge shaped by design. So if the pitch is 4 or less it will create a flat spot. On a 2 it would actually be directing water toward your cut.