If you re considering turning your attic into conditioned storage or living space it s worth changing tactics to insulate between the rafters and wall joists instead of the floor.
Insulating attic as conditioned space.
Install insulation along the underside of the roof deck of an unvented attic rather than on the ceiling deck of a vented attic for either of two reasons.
Hire a pro to install spray foam insulation.
In an unvented attic assembly air impermeable insulation is applied directly to the underside of the structural roof deck and is tied into the insulation located in the walls so that the roof system becomes part of the insulated building enclosure.
The insulation reduces wildly high temperature spikes and so the attic becomes a conditioned part of the home like any other room.
When hvac equipment is in the attic insulation and an air barrier at the roof line brings that equipment within the conditioned enclosure envelope thereby allowing it to operate in more favorable temperature and humidity conditions without air leakage and heat loss gain directly to the exterior.
Here s the answer to the question posed in my article title.
To provide an unvented conditioned space for locating hvac equipment in the attic and or to provide a continuous thermal barrier for designs that have complex coffered ceiling planes and or numerous penetrations for lights speakers vents soffits etc which make it difficult to achieve an airtight ceiling plane.
However in a traditionally insulated attic insulation on the ceiling the attic is vented.
Minimize thermal bridging and reduce heat loss through the foundation protect the damp proof coating from damage during backfilling provide some protection against moisture intrusion make the.
In new construction adding insulation on the exterior of the basement walls will do the following.
You can use rigid foam panels or do as tom silva does with nearly all houses these days.
When spray foam is installed on the underside of the roof deck the attic space is insulated from heat that otherwise would be entering the attic.
The attic space becomes indirectly conditioned as a result of the air leakage heat transfer and vapor diffusion through the ceiling.