# Attic Insulation - Strange Pipe



## gpraceman (Aug 18, 2012)

I was trying to get my attic insulated better, and ran into a pipe that I couldn't figure out what it was for. It is a relatively thin walled white pipe and has no markings on it. I have accounted for all of the vent pipes for the bathrooms, so I'm thinking that it isn't a vent pipe. The vent pipes all penetrate the roof and look to be a thicker walled PVC and have black markings.

Since it is next to the furnace flue, I checked the basement to see if it originates there, but couldn't see anything like it.

I thought that it might have been installed as a future way to run wires. If that is the case, then why didn't they run the bundle of wires near the flue through it?

I'm not sure that I can find out where it goes without tearing into the wall of the void it runs through.

I was tempted to cap it off, but I ended up extending it up a couple of feet so it would not get buried under the new insulation that I was blowing in. I would still like to know what is up with that pipe.


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## joecaption (Nov 30, 2011)

Anyway there used to be a hot water heater up there?
SCH is sometimes used on the relief valves.


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## djlandkpl (Jan 29, 2013)

Tie a weight to a length of string and drop it down the pipe. When it stops, mark the string, pull it out, and then measure the distance traveled. It might give you a clue where is goes. The weight might stop early if there is a 90 degree bend in the pipe.


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## gpraceman (Aug 18, 2012)

There hasn't been a water heater in the attic. This is a two story house, built in 2000, with the furnace and water heater down in the basement.


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## CitadelBlue (May 23, 2013)

Maybe someone thought ahead.... Since the pipe is running parallel to the furnace flu in the basement ..... it could be a conduit for future electric, cat and cable wires from the basement to attic/2nd floor....


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## gpraceman (Aug 18, 2012)

I could not find the end of that pipe in the basement. The flue goes down a void space. How far that pipe goes down the void, I'm not sure, as that would mean tearing open drywall. If it was meant as a wire run, I would have thought that they would have run the bundle of alarm and coax wire, that you can see near the flue, through it.

Now that adding more blown in insulation to the attic is done, I'm not sure that I want to disturb it to try djlandkpl's suggestion. If I have a compelling reason to go into the attic in the future, I'll give that a try.


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## Dragfluid (Dec 30, 2013)

Did you take a whiff and detect any odors coming from it?


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## Windows on Wash (Aug 30, 2011)

I am going to guess some venting but depending on the age of the home, it should have been through the roof.

Perhaps a conduit as mentioned before.

The string method will give you the stopping point.


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## gpraceman (Aug 18, 2012)

Old thread I know, but I finally was able to figure out what this pipe was for. The end in the basement was well hidden, but it terminated in the ceiling right above our IC panel. So, CitadelBlue was correct, someone thought ahead. I used this pipe to run a Cat6 cable up to the attic so I could add a ceiling mounted wireless access point to our 2nd floor. Just dropped the cable down the pipe and connected it to the access point and the switch in the panel. Saved me a ton of work of trying to otherwise get a cable up to the attic.


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## JoshInWi (Oct 10, 2018)

gpraceman said:


> Old thread I know, but I finally was able to figure out what this pipe was for. The end in the basement was well hidden, but it terminated in the ceiling right above our IC panel. So, CitadelBlue was correct, someone thought ahead. I used this pipe to run a Cat6 cable up to the attic so I could add a ceiling mounted wireless access point to our 2nd floor. Just dropped the cable down the pipe and connected it to the access point and the switch in the panel. Saved me a ton of work of trying to otherwise get a cable up to the attic.


That's awesome! Thanks for the follow-up.


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