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DzNtz
LSU Fan
BR
Member since Oct 2007
621 posts

Ductwork condensating throughout attic
Looking for recs on someone that can either reinsulate old hard pipe ductwork in attic or replace with new flex if that’s a better option. Ductwork is approx 35 years old and insulation is sagging and leaking condensation on ceilings in several spots. In Baton Rouge


s14suspense
USA Fan
Baton Rouge
Member since Mar 2007
14238 posts

re: Ductwork condensating throughout attic
Following this... Had local company give me a quote for 12 new drops of flex and a new plenum for >$3500 I want to say. Only 2 of them are real bad and some of them run long distances around the house that don't seem to need replacing.


easy1234
LSU Fan
Baton Rouge
Member since Oct 2010
125 posts

re: Ductwork condensating throughout attic
First check for air leaks if no leaks. I bought insulation for duct foil outside and wrapped and stapled the old duct.


s14suspense
USA Fan
Baton Rouge
Member since Mar 2007
14238 posts

re: Ductwork condensating throughout attic
quote:

bought insulation for duct foil outside and wrapped and stapled the old duct.


I did the same thing, patched some obvious spots where there were gaps in the insulation Friday night but it hasn't been hot enough for the problem to show back up recently.


Cracker
Montana Fan
in a box
Member since Nov 2009
11480 posts
 Online 

re: Ductwork condensating throughout attic
No way I would replace hard duct with flex crap.
Have it re taped Sealed and insulated


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70
CrawDude
LSU Fan
Baton Rouge
Member since Apr 2019
2432 posts

re: Ductwork condensating throughout attic
I think I would also be inclined to keep the rigid ducts if they are sized properly and not in to bad of shape not because flex ducts are bad but they often seem to be installed improperly with many kinks/bends, etc that restrict air flow, but then that should not be an issue with a good installer.

But as Cracker recommends, I would have a duct blast test performed to check for air leakage, have all leaks properly sealed with HVAC mastic and then insulated with R-8, unless it’s best to go the flex duct route. Sounds to me you have duct leakage if you have sagging and dripping duct insulation.

Someone I know with knowledge of this general subject recently suggested this firm to me Entergis in BR as a company to consider as I also want to have my HVAC ducts and house envelope checked for air leakage prior to HVAC replacement but I haven’t reached out to them yet.

I’ll also be following to see what, and who, others might recommend.

This post was edited on 7/28 at 8:49 am


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21
keakar
Member since Jan 2017
15202 posts

re: Ductwork condensating throughout attic
all the comments are good but double check your power vent fan is working, check the simple stuff first.

that said, making sure things are well insulated is never a wasted effort but you gotta remember to do it in winter time when its not 150 degrees up there like it is now. since we have rainy conditions all week try going up there after midnight and it shouldnt be any hotter then 90 degrees


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10
Hamma1122
Member since Sep 2016
10694 posts

re: Ductwork condensating throughout attic
Wait till November and do yourself


glorymanutdtiger
LSU Fan
Baton Rouge
Member since Jun 2012
2038 posts

re: Ductwork condensating throughout attic
Having the same problem in Baton Rouge. I re wrapped some of the spots with insulation wrap. I might have to do little by little or wait till November.

I'm also on raised home with old wood flooring. Humidity is not my friend.

This post was edited on 7/28 at 8:14 am


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10
glorymanutdtiger
LSU Fan
Baton Rouge
Member since Jun 2012
2038 posts

re: Ductwork condensating throughout attic
Do you have two units and how big is the house for that price quote?


s14suspense
USA Fan
Baton Rouge
Member since Mar 2007
14238 posts

re: Ductwork condensating throughout attic
quote:

Do you have two units and how big is the house for that price quote?



Two units, yes but I think that was a quote for just the one bigger unit. ~3K.


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easy1234
LSU Fan
Baton Rouge
Member since Oct 2010
125 posts

re: Ductwork condensating throughout attic
Ok is it condensing at registers or in attic. If is't register it sucking air from plenum or cooling coil. If it condensing in attic more insulation check for leak also I put radiant barrier on the ceiling help keep attic cooler.


diat150
Tulane Fan
OPELOUSAS
Member since Jun 2005
33734 posts

re: Ductwork condensating throughout attic
What’s air flow like in the attic? A few fans in the attic may help keep the condensation from forming until you can work on it.


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DzNtz
LSU Fan
BR
Member since Oct 2007
621 posts

re: Ductwork condensating throughout attic
Condensating in attic and dripping on ceiling in two spots. Also on grills but that doesn’t concern me too much. Old insulation is sagging and wet in a lot of areas that have not started dripping yet.

Airflow in attic is minimal. Might try that. Got ac company coming by to give me a price on reinsulating.


s14suspense
USA Fan
Baton Rouge
Member since Mar 2007
14238 posts

re: Ductwork condensating throughout attic
quote:

Got ac company coming by to give me a price on reinsulating.


Share the details on that please.
Luckily it’s not been hot enough for it to be a issue recently.


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Rhino5
Auburn Fan
Atlanta
Member since Nov 2014
21536 posts

re: Ductwork condensating throughout attic
Get up there and check first. I found stain one morning on the ceiling and got up in the attic and noticed the glue/adhesive from the duct had partially come undone. $5 trip to Lowe’s and patched up myself, no issues since.



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SaintDb
Member since Sep 2011
45 posts

re: Ductwork condensating throughout attic
Sounds like the ducts are reaching dew point or improperly sealed. Do you have a variable speed unit(s)?


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s14suspense
USA Fan
Baton Rouge
Member since Mar 2007
14238 posts

re: Ductwork condensating throughout attic
quote:

DzNtz


Any update on this?

Went and checked mine yesterday evening since it was hot again and the insulation on the worst line was only damp to the touch instead of sopping wet like it had been at its worst.

One thing I noticed was the cold air coming out of the evap? coil box where the insulated copper line goes in and the naked copper line comes out and oddly enough the PVC drain line had cold air blowing out of the top of the pipe you pour bleach in. Should that be capped normally?


DzNtz
LSU Fan
BR
Member since Oct 2007
621 posts

re: Ductwork condensating throughout attic
Still waiting on price. Was supposed to hear back by this evening. Will report back when I hear something


DzNtz
LSU Fan
BR
Member since Oct 2007
621 posts

re: Ductwork condensating throughout attic
Got a quote for $2500 to reinsulate all the ductwork. Never heard back from other company. However this new quote is from a fella that doesn’t speak the best English. Will be sure to inspect his work as he goes.


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