What's so bad about having insulation contractor work before HVAC contractor?


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Old 01-07-13, 10:14 PM
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What's so bad about having insulation contractor work before HVAC contractor?

Hi. I am doing a new construction project. I understand that the HVAC contractor generally is scheduled to work last, after the insulation workers install the new insulation. But, I am wondering... What's so bad about having the insulation contractor work before the HVAC contractor?
 
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Old 01-07-13, 10:19 PM
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I understand that the HVAC contractor generally is scheduled to work last, after the insulation workers install the new insulation.
Not where I come from.
We electricians rule the roost on construction sites but usually the duct work goes in early and way before the insulation is installed.

OR are we talking about ductwork in an attic ?

Normally.....the insulation is the last thing to be done....after duct work is in and inspected.
 
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Old 01-08-13, 05:07 AM
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You definitely want the duct work installed before insulating. Think about where ducting needs to be and then think about where insulation goes. How can ducting be installed with insulation in place... by removing the insulation. You also want insulation to be tight fitting around any ducting to prevent air infiltration and that can only be done after the duct is installed.
 
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Old 01-08-13, 09:14 AM
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Oh dear me. I accidentally wrote the wrong thing backwards in my initial sentence. I should have written... That I think the HVAC contractor works BEFORE the insulation contractor, not that the HVAC guy comes in last. Oops sorry. My bad. Anyway, my question about why is it so bad about having the insulation guy go after the ducting goes in was well answered. Thanks PJmax and Pilot Dane.
 
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Old 01-08-13, 09:19 AM
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I'm just wondering... If the ceiling ducting goes in first, then how is it possible to get insulation above the ducting afterwards? Seems like it would be really, really difficult.

In a new construction, after the framework is up... What is the order of operations for electricity, plumbing, HVAC, etc?
 
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Old 01-08-13, 09:24 AM
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All the mechanicals are roughed in shortly after the framing is done. They can pretty much be done in any order or at the same time. It's mostly decided by the contractors [and subs] scheduling. After the HVAC, elec and plumbing is roughed in and inspected, they'll insulate the walls followed by hanging the drywall.
 
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Old 01-08-13, 09:31 AM
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Just based on personal experiences.........get the plumbers and HVAC guys there first. Their locations are pretty much set and as their lines are more ridgid......they can't be moved in the future.

If you get the electrician in there first and he runs wiring.....there is a risk of it being in the way of a duct or plumbing drain line.
 
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Old 01-08-13, 09:37 AM
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How they insulate depends on how a building is constructed but probably most common with an attic the insulation is blown in after the wiring, HVAC and sheet rock have been installed. There's usually a truck in the driveway with a really long hose and the insulation is blown through the hose. It comes out the end almost like snow and blankets everything.

Around here the house is framed and the roof must have at least tar paper before any wiring can begin. Work usually progresses by what is most limited by it's nature which is often plumbing. Drain lines have to go where they are called for in the plans and they must have the proper slope and work their way through the structure of the house. You don't want drain lines to have to divert because of wires. Next is duct for HVAC. It's not limited by having to slope like drain lines but the pipes are big. Lastly comes wiring because it's easiest to snake around obstacles. Often though the rough electrical is done early on. A good electrician is mindful of the trades to follow and runs the wires out of the way and up close to framing to stay out of the way of other, bigger stuff. Then the walls are insulated and sheet rock hung. Then the insulators come back after the ceiling sheetrock is up and do the attic space.
 
 

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