# Roofing Vent Installation



## Jay Martin (Jan 2, 2021)

When HVAC cuts a hole in the roof for
their vent what is the industry standard of how big the hole can or should be?
Do shingle manufacturers have a spec on how large this can be?


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## OldNBroken (Apr 20, 2019)

They have to cut their hole per local code jurisdiction. Depends on what they are venting. If it's just a bath or kitchen exhaust vent then they need to cut a hole big enough for whatever they are installing.  Same with PVC or ABS
If it is a mechanical vent. ie b vent or the like, it must have minimum 1" clearance from combustibles.

So, what is the vent?


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## Jay Martin (Jan 2, 2021)

OldNBroken said:


> They have to cut their hole per local code jurisdiction. Depends on what they are venting. If it's just a bath or kitchen exhaust vent then they need to cut a hole big enough for whatever they are installing.  Same with PVC or ABS
> If it is a mechanical vent. ie b vent or the like, it must have minimum 1" clearance from combustibles.
> 
> So, what is the vent?


the vent that I am referring to is a type b vent .


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## Jay Martin (Jan 2, 2021)

It does not have a roof jack, nor does it have the 1” of clearance. But I’m wondering if the hole is too large or does that not matter?


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## roofermann (Jul 7, 2012)

Jay Martin said:


> It does not have a roof jack, nor does it have the 1” of clearance. But I’m wondering if the hole is too large or does that not matter?


That hole would be OK if the flue pipe were centered, as is it's a code violation. Are sure it doesn't have a jack? That's the flashing on the outside that ties in with your shingles/tiles etc.


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## OldNBroken (Apr 20, 2019)

What he said ^^^^^^
It appears to be too close to the framing as well as the sheathing. That is a safety issue and should be corrected.


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## roofermann (Jul 7, 2012)

Biloxisfinestx said:


> Dang! thats one crazy hole. I had a similar issue. I called this experienced Biloxi MS roofer. he did an amazing job.


Uh, you ARE that guy you called yourself?


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## OldNBroken (Apr 20, 2019)

Yes, yes he is. I always wondered if moronic posts in forums like that actually manage to drum up business.


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