Melted Plumbing Vent Stacks & Boots?

Found this today on an inspection. I wanted to know if any of you guys have seen this before? The plumbing vent stacks and flashing boots were melted above the roof shingles. They were located within 10 feet of the chimney. The chimney had a large horizontal separation crack inside the attic under the roof decking, but there were no signs of heat damage to the vent stacks inside the attic, only at the exterior. This was a pre-listing inspection for my client, and they are the original owner. There is no history or evidence of any chimney fires. It gets hot here in Atlanta during the summer months, but not hot enough to melt PVC. The roof has been replaced within the last 11 months. Any ideas? (See attached photos) Thanks for any feedback.

Chimney Crack.jpg

Chimney Crack.jpg

Vent Stack 2.jpg

Chimney Crack.jpg

Melted Vent Stack 1.jpg

Roof & Chimney Area.jpg

Vent Stack Under Roof Decking.jpg

Melted or damaged during roof replacement?

The homeowner did not know. The roofing contractor did not mention anything to the home owner about the vent stacks and boots being damaged. It might of happened after the new roof was installed.

The melting point of lead is
**621.43 °F)

What besides fire could get that hot.?

LEAD covered

That’s what it looks like to me Buck. Did you traverse the roof, or observe from the eaves? Did you actually get your hands on it?

It was to hot to touch.:smiley:

Thats an expensive jack to use on a comp roof what a waste of money. Its a lead jack typically used on tile roof waste vents. They cover the entire waste vent & are folded down inside the ABS water tight & ugly.

looks like lead to me. Probably looks a little deformed from being pounded on with a hammer on the reroof.

No. The vent stacks were all PVC. The upper exposed sections are just spray painted black.

I also thought it was lead covered and the roofers beat it to death.

Now, after closer look I see pvc.

Testing to the ASTM D 4803Standard Test Method for Predicting Heat Build-up in PVC Building Products indicates that radiant heat from the sun can increase pipe surface temperatures by 50ºF or more,]( 44

The black paint would help increase temperature.

How far away is pic. 2 from chimney? Did you look inside the chase?

IMO if the heat from chimney caused that there would also be a sign of damaged shingles.

Looks like a lead sleeve, also look like it may have been the wrong size for the pvc pipe it covers and it beat into submission to fit.

Picture #2 was about 7 feet from the chimney. Picture #3 was directly behind the chimney. There appeared to be more damage to the vent stack furthest from the chimney. The roof was recently replaced, so there were no signs of damaged roof shingles, no signs of excessive heat or damage at these areas underneath the roof decking inside the attic. I am wondering if there may have been enough heat coming from the separation crack inside the attic at the chimney to cook the underside of the roof decking and previous shingles to cause the plumbing vent stacks & boots to melt. The chimney has a metal flue pipe that ran through the brick chimney chase. Could there have been enough heat radiating from the metal chimney flue pipe to cause high enough temperatures to melt the PVC plumbing vent stacks & boots? It sounds far fetched, but I’m not sure what else could have caused enough heat to melt the PVC plumbing vent stacks.

Here is a better picture of the PVC melted vent stack and boot. This zoomed image also shows where the top of the vent stack has melted shut.


The metal flue pipe should be a B-vent which only requires a one inch clearance.

I would have the owners replace both pvc vent stacks at roof by cutting them off in attic and attach new extensions and have tuckpointing repair at chimney to avoid any problems with potential buyers.

You may also recommnd a A Level II Inspection for fireplace to be on the safe side.

Are you sure they are plumbing vent stacks? Not for furnace or water heater.

Yes. The furnace & water heater type B vent pipes were located at the backside of the roof. I verified that both melted PVC vent stacks were originating from the bathrooms below.