Roof Mastic on Flue Vent

Had a furnace flue vent with a lot of roof mastic on it. Does this fall into the category of clearance around the B vent?

Possibly yes the roof cement could be flammable.


Is wrong but; 1/ it is a double wall pipe and is not going to catch fire. 2/ no it is not about clearance it’s about the material used.

Do you have a picture from the outside?

No, its the only picture. I’m confused by your reply. Would you consider this an issue?

How in the hell did they manage to put that amount of mastic on a flue vent pipe?
The roof flue vent flashing installation is a: wrong, b: wrong, c: wrong…

1: The roof deck sheathing cutout too large/wide for the flashing.
2: Wrong style/size of roof vent flashing adaptor.
3: Mastic on a furnace flue vent.

There isn’t any PLASTIC CEMNT applied to flues. Plastic cement is applied to the flashing prior shingle being installed atop the flashing. A bead of flue mastic is applied at the flashing thimble pipe intersection.

Observation: Non professional flue flashing workmanship.

**Heating: **
Observation: Suspect: Reams of roofing summer grade plastic cement smeared atop furnace flue vent pipe…Does not appear to be flue pipe mastic. Location. Below the furnace flue vent flashing.
Recommend: A licensed HVAC furnace installation and repair contractor change the flue pipe and instal a properly sized slope/pitched roof flashing.
*Note: Flammable liquid and vapour. May be fatal if swallowed and enters airways. Harmful if swallowed. May cause respiratory irritation or drowsiness or dizziness.

Your from Texas and HI is run by Realtors. You need to ask them…

There is a difference between ‘Issue’ and ‘defect’.
Yes, it is an ‘issue’ as it is an inappropriate installation repaired with an inappropriate material.

I don’t understand why you don’t have a pic from the outside.
Were you giving a 50% discount to do half the job?
There’s more to be seen outside and needed to make any call about this photo.