Confused in NC about Mechanical Room Air and Insulation Requirements
I purchased and have nearly completed the remodel of a 1972 brick ranch in Raleigh, NC with west-facing daylight basement (on the back and one side). During the upstairs remodel I installed continuous drywall walls and ceiling before installing new interior-walls. For existing walls I used spray foam in the attic to air seal them. Downstairs I caulked and insulated rim joists and followed the steps in https://www.greenbuildingadvisor.com/article/installing-rigid-foam-concrete-slab to insulate and air seal the walls and floor. Where I had load-bearing walls bearing on concrete, I sealed the sill to the floor with “big stretch” caulk. I thought I had done the best I could considering the age of my house; however, I think, I have failed in the mechanical room and can use some advice please. I have not installed any XPS on the one exterior wall in the mechanical room or the concrete floor (slab only has vapor under the 4” concrete.) I’ve not considered the floor in this room because some of it has vinyl flooring on it and all the appliances are sitting directly on the concrete – direct vent furnace, heat pump H20 tank and well water treatment tanks. I’m trying to understand what I need to do to properly treat this as space inside my building envelop – air seal and insulation. I spoke the company I used to blow insulation in the attic and they told me I need to either insulate the walls between the mechanical room and the finished space above, install a 6 mill plastic-type barrier over that and insulate all the water lines or they could spray it all with foam. Does that sound right? Advice on how to properly manage this to keep this in my building envelop and not end up with an airtight musty room would be more than appreciated.
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