Home>Discussions>INSULATION & HVAC>Insulating the basement ceiling
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Re: Insulating the basement ceiling

Here in NH a basement must be insulated in one of two ways in order to pass the current energy code. You either need to insulate the basement ceiling/first floor or you need to insulate all the basement walls from the slab up to the insulated walls above. If you don't do this the energy code audit will not pass.

Re: Insulating the basement ceiling

Interesting ... hard to imagine that insulating the basement ceiling would be a requirment or an alternative .... the walls make sense.

Around here it was mandatory for the top 4 feet of the basement wall in the past .... it was changed to be the entire basement wall ... no requirement for the ceiling and wouldn't be an alternative.

Personally don't see a major advantage insulating the basement ceiling.

Goes to show the difference from region to region.

Re: Insulating the basement ceiling

I didn't say it made sense. The idea here really comes down to insulating the complete conditioned space. So, if you say that you're not heating your basement (regardless of what heat comes off your boiler) then you'd insulate the floor. If you intend on heating the basement then you would do the walls. In theory it makes sense. Most of the new homes we build now get the floor insulated.

Re: Insulating the basement ceiling

Here in MN we don't insulate the underside of the floor that separates the basement and the upper level but we do insulate the basement walls even if the basement isn't heated.

Re: Insulating the basement ceiling

Even though you may not have heat runs open in the basement, your basement is still unintentionally conditioned having combusiton appliances there, with heat runs and the flue pipes radiating heat. You must also be careful if you seal this area off that the volume of the basement that houses the combustion appliances (also known as the combustion appliance zone, or CAZ)has enough air to supply the units to burn properly. I would not recommend insulating the floor, but it you do, install unfaced fiberglass or slash the paper to allow it to breath, or you could end up with moisture/condensation problems. Same goes for interior walls.


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