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Conditioned Attic: Can I add insulation to the floor?
- Thread starter johnu
- Start date
Firebrick43
Well-known member
Any water lines or condensate? Ducts insulated or bare metal?
Arizona, so a hot attic?
Fiberglass batt insulation doesn't do much to block radiant energy. If your roof is heating up from daytime solar and the underside of the roof sheathing is turning in to a huge radiant panel, that radiant will hit the attic floor, heating up the ceilings of the rooms below. Putting unfaced batts on the attic floor will prevent some of the radiant gain but not all. With a hot attic and warm batt insulation on the attic floor, conduction will make the ceilings below warmer as well.
With HVAC and ducts in the attic space I prefer to bring the attic inside the thermal envelope of the house, even with insulated ducts.
Fiberglass batt insulation doesn't do much to block radiant energy. If your roof is heating up from daytime solar and the underside of the roof sheathing is turning in to a huge radiant panel, that radiant will hit the attic floor, heating up the ceilings of the rooms below. Putting unfaced batts on the attic floor will prevent some of the radiant gain but not all. With a hot attic and warm batt insulation on the attic floor, conduction will make the ceilings below warmer as well.
With HVAC and ducts in the attic space I prefer to bring the attic inside the thermal envelope of the house, even with insulated ducts.
Tile roof, no condensation, ducts are all insulated. I guess my best play is to go around and push back into place the few dislodged and hanging down insulation rows.
Being a 1988 build I figured improvement could be found.
My Flir thermal camera shows areas with heat on the ceiling.
Would a perforated radiant foil barrier stapled to the truss help? I guess it would best work on the top of the truss, 6” below the roof sheathing and well above the insulation.
Thanks for helping!
Being a 1988 build I figured improvement could be found.
My Flir thermal camera shows areas with heat on the ceiling.
Would a perforated radiant foil barrier stapled to the truss help? I guess it would best work on the top of the truss, 6” below the roof sheathing and well above the insulation.
Thanks for helping!
Last edited:
Firebrick43
Well-known member
A foil barrier needs an air space to reflect back into. They work well on the bottom side of rafters on an house with a conventionally insulated ceiling.Tile roof, no condensation, ducts are all insulated. I guess my best play is to go around and push back into place the few dislodged and hanging down insulation rows.
Being a 1988 build I figured improvement could be found.
My Flir thermal camera shows areas with heat on the ceiling.
Would a radiant foil barrier stapled to the truss help?
Thanks for helping!
I would be dubious that it will do much with that space occupied by insulation.
Pulling out the fiberglass and putting the same thickness of polyiso sealed at the edges would significantly boost performance.