Proper Insulation For Vaulted Ceiling

Have a newly framed vented cathedral ceiling to insulate.

Proper insulation for vaulted ceiling.

How should you insulate. Then you need to determine the amount of material needed for your ceiling. Some builders rely on batts with attached kraft paper facing to do that job but tom recommends unfaced batts covered in plastic with all the seams taped shut. Cut and insert 1 or thicker high r foam insulation sheets r 8 per inch against the furring giving a 1 or greater air path between the insulation and the roof deck under the cathedral ceiling.

This density prevents air from carrying damp into the insulation. Be sure to seal around any pvc pipes as well. Straight bays 2x12 24 o c. Nail 1 furring along every rafter side against the roof deck.

How to insulate a vaulted ceiling installing a vaulted ceiling requires careful consideration of the building codes in your area. Instead most builders prefer a foam spray insulation either cellulose or urethane which can be placed into the ceiling using a spray can and left to dry. Seal all ceiling openings. Check the joists and wall plates for any holes or openings.

Honestly if you ve done your prep work properly you can use cellulose spray foam fiberglass recycled denim or horse hair and your home will be relatively well insulated and energy efficient. Fiberglass insulation comes in lightweight batts and rolls precut to widths that match standard stud and rafter spacing. Cellulose insulation s higher r value is very important in limited space areas such as a cathedral ceiling cavity. The current plan is to use batts of some kind in the bays take care to air seal the interior surface avoid penetrations air seal the vent channel too bays fully sealed double prime the inside surface for vapor resistance.

Stand on a ladder and using a caulk gun seal any areas where there is visible wiring or plumbing. This will protect the room from air infiltration and will also suppress fires. After you ve reduced humidity problems in your home then air sealed the ceiling between the living space and the attic cathedral ceiling then you can insulate. Plus with fiberglass batts you must leave ventilated space further diminishing the insulating potential of the cavity.

Foil faced batt insulation is often used in cathedral ceilings because it provides the permeability rating often required for use in ceilings without attics. Like other batt type insulation fiberglass has a predictable r value if not compressed but is difficult to fit around obstacles without leaving gaps. However don t make the mistake of using a lot of foam spray insulation as this stuff is expensive. You also need to make sure that you are leaving at least 2 inches of breathing space between the insulation and the roof sheathing.

A vent baffle should be installed between the insulation and the roof decking to maintain the ventilation channel.