Mechanical Rough-In

posted in: Museum Mews, Rough-In | 0

Another important milestone today – the mechanical and electrical systems are starting to be installed.  This includes the plumbing and HVAC (air conditioning) as well as the outlets, light switches, recessed lights, and other light fixtures.  The security system, phone lines, TV lines, and internet wiring is considered low voltage and will be installed by yet another vendor.

At this stage, the builder’s role as coordinator between different sub-contractors is more important than ever. You have several trades coming together to “utilize” a limited amount of space (inside the walls and ceilings) to layout their pipes, conduits, wiring, boxes, etc.  There’s a lot going on and the challenge is to manage the competing interests of each sub-contractor while making sure that the decisions they are making on a micro level makes sense.  Each vendor would like to complete the job as soon as possible and therefore the default approach is to always take the path of least resistance.  It’s human nature.  But that doesn’t always make sense.  Just a small example is the plumber who installs his drain line below the ceiling to get around an obstruction, creating more work for the framers to build a fur down later, just because he didn’t want to put in a few extra elbow joints.

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Exterior recessed lights. Check to make sure they are evenly spaced in the ceiling.
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Exterior wall electrical outlet box penetration. Need to improve the weather proofing here.
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Recessed lights and HVAC supply registers in the ceiling. Need to make sure nothing looks too goofy.
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Furnace and other equipment in the attic. The furnace vents through an approx. 10″ metal pipe through the roof. An item called a “roof jack” must go over the pipe penetration in order to weather seal the pipe. Otherwise, it WILL leak and damage the equipment underneath! The HVAC crew does not install the roof jack, the roofer does that. Therefore, this is an area that requires the builder to intervene and help coordinate.
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Flex duct run up a “chase” and through the floor above. The 90 degree turn there looks a bit too tight. Ducts do not like to be crushed like that, as it impedes air flow and decreases performance of the system. Another item to put on the sub’s punch list.