Replacing Chimney Pipe - Can't get old pipe off

[abrucerd]

During my spring cleaning, I found that my existing chimney pipe (metalbestos SS - class A) was corroded (documented here: https://www.hearth.com/talk/threads/37916/).

After speaking with a few folks, I decided to try and replace the top 18" of pipe myself. I bought a new section of pipe, and a new storm collar, and went up to the roof today to give it a shot. I removed the caulking and the old storm collar, but couldn't get the old pipe out. I was able to twist it... even 360 degrees, but I wasn't able to pull it up and out.

After looking through the pipe with a flash light, it looks like the pipe is connected to another piece of pipe beneath/within the roof flashing... I'm guessing there's something "locking" those two pieces of pipe together.

My question for anyone who works with chimney pipe routinely.... first, does this sound accurate? second, is there an easy way to seperate the pipe so I can take the old piece off WITHOUT taking apart the flashing? If not, how big of a job is it to take the flashing off, and put it back (obviously, i'm not a roofer)?

Thanks all!

 

[abrucerd]

bumping for assistance

 

[imacman]

abrucerd, as I remember, you have the same or similar pipe as I do for the top of my install....mine was originally for a wood stove I had. The top sections that went through, and above the roof, were locked by rotating, but also had a locking "ring" around the joint.

I had to remove that before I could get the pipes apart. Mine was just a sheet metal screw going through 2 tabs, on on each end of the ring, and as you tightened the screw, the ends of the ring would close, clamping the two sections together.

I didn't know why I couldn't get the sections apart either until i got a flashlight and really looked.

Hope this helps.....

 

[abrucerd]

thank mac,

you're right about the locking ring... and my guess is that locking ring is beneath my vent flashing. If I dislodge my flashing, and am able to replace the old pipe... can I reuse the same piece of flashing, or do I need a brand new one?

maybe this would be a better question to ask at a roofing forum...?

 

[jtakeman]

You should be able to reuse if removed cleanly. I am asuming it is tin and sealed with black goop. Warming it up helps remove. Heat gun or torch. I warm the putty knife not the roof.

I would warm up a putty 2" knife and carefully slide it around the sealed joint. Tough to start but once its going it should go easy. If it starts to get tough warm the knife again.

Reseal with roof tar or similar. Lay some tar on roof. Lay the flashing into it. Also add some tar to the top. Use an ample amount.

jay

 

[abrucerd]

Thanks Jay,

The flashing is nailed down, as well as sealed with roof cement. I hadn't thought about chipping away at the roof cement, but I like your suggestion. I'm more concerned about the nails, however... can I put new nails in the same spots?

 

[jtakeman]

Yes, You can put them in the same holes. I would put some tar in the nail holes first(helps to seal). The goop will hold it down once it sets. The nails are there to hold it while it sets. You could add a few extra nails if you want. Don't get to carried away though.

jay