Moving heat duct between joist to over I-beam

Don Ferguson · 11-25-2012, 08:12 AM

Woud like to re-route heating duct in basement up between joist over I-beam verses current installation where the ducting is installed under I-beam. What are my options.

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**Garry Sorrells** · 11-25-2012, 08:41 AM

Become knowledgeable about the sizing and friction for the alterations that you want to make. You could inadvertently create a problem with the distribution to the rooms. Changing ducts willinilly is not good.

**Billy Stephens** · 11-25-2012, 04:59 PM

Originally Posted by Don Ferguson

Woud like to re-route heating duct in basement up between joist over I-beam verses current installation where the ducting is installed under I-beam. What are my options.

Do Not Cut the I-Beams to reroute HVAC ducts.

Don Ferguson · 11-26-2012, 06:29 PM

Originally Posted by Garry Sorrells

Become knowledgeable about the sizing and friction for the alterations that you want to make. You could inadvertently create a problem with the distribution to the rooms. Changing ducts willinilly is not good.

Duct is 14 inches wide by 8 inches - spacing above I-beam is 14.5 inches above. Should be able to squeeze ducting through space - question is what insulation is required to run the duct in between the joist. Will make sure air flow is not affected. Will have it done by HVAC person.

**Billy Stephens** · 11-26-2012, 06:44 PM

Originally Posted by Don Ferguson

Duct is 14 inches wide by 8 inches - spacing above I-beam is 14.5 inches above. Should be able to squeeze ducting through space - question is what insulation is required to run the duct in between the joist. Will make sure air flow is not affected. Will have it done by HVAC person.

The Ducts themselves are lined with insulation.

**Vern Heiler** · 11-26-2012, 07:51 PM

Originally Posted by Billy Stephens

The Ducts themselves are lined with insulation.

Hopefully! Older homes that only had heat were not insulated. Thump the duct with your screwdriver handle to be sure its insulated.

**BridgeMan** · 11-26-2012, 08:07 PM

The photo makes it look like there will be less disruption to the air flow if the duct is routed over the I-beam than there is in its current configuration (below the beam). The result of less offset, assuming the tapers/transitions are as smooth as they currently are.

And FWIW, the beam looks more like a wide-flange (WF) beam than an I-beam. Very few I-beams are used anymore, but were popular back in the 30s and 40s. WF beams have constant-thickness flanges, while I-beam flanges were tapered, being thicker near the web.

**Raymond Wand** · 11-26-2012, 08:23 PM

Don

You don't want any insulation lining the interior of the supply, nor do you require any on the exterior.

I see why they ran the duct under the beam as the joists on the far side of the beam run parallel with the beam, so you will have to use two 90 degree elbows when you run it over the beam, down to 2nd 90 deg. elbow and out under the floor joists.

**Garry Sorrells** · 11-27-2012, 04:53 AM

From the picture it would seem that you could run over the beam without a problem other that having to add to the lengths of the run to reconnect. Sheet metal work pure and simple. HVAC guy can do it faster than you with less aggravation to you. . But you could do it also. No insulation involved to rework what you show in the picture.

It may be cheaper to let a HVAC mechanic do the job and save you the cost in band aids or the trip to the ER for stitches.

**H.G. Watson, Sr.** · 11-27-2012, 07:21 AM

What is directly above this beam? (suspect loading wall, note solid blocking) looks to be bearing from below. Distance of joists (span?). Looks to be "by 8" which are less than 8". Suspect not a "duct" but a "trunk". Basement area currently no habital space? Where are the beam supports in relation to the heating plant? Ducts & trunks tend to expand and contract as they are heated and cool, popping noises, creeking, ticks, you won't be happy impinging or abutting to the subfloor or joists.