Can a cathedral ceiling be an R-30?

In other words, you can sometimes get away with an R-30 cathedral ceiling — but only if the rafters are too shallow for more insulation, and only if the cathedral ceiling area is either (a) 500 square feet or less, or (b) unless the cathedral ceiling represents no more than 20% of the total insulated ceiling area.

How big of a ceiling do you need for a cathedral?

Note that if 20% of the ceiling area is 350 square feet, you can’t install R-30 insulation in a 500-square-foot cathedral ceiling — you are limited by the 20% rule. Similarly, if 20% of the ceiling area is 600 square feet, you can’t install R-30 insulation in a 600-square-foot cathedral ceiling — you are limited by the 500-square-foot rule. 4.

When did cathedral ceilings start to be insulated?

Insulated cathedral ceilings are a relatively recent phenomenon. The craze for insulated cathedral ceilings (and great rooms) really took off in the 1970s and 1980s, when examples began popping up like mushrooms after a warm rain. In those days, most builders stuffed cathedral ceiling rafter bays with fiberglass batts.

What kind of Batts are used in cathedral ceilings?

In those days, most builders stuffed cathedral ceiling rafter bays with fiberglass batts. Sometimes they included flimsy Proper-Vents between the fiberglass and the roof sheathing, but often they just specified thin batts to ensure that there would be an air space above the batts for ventilation.

What to use to open up cathedral ceiling?

Open Up a Ceiling With a Steel Sandwich — An angled steel flitch plate bolted between rafters eliminates the need for rafter ties in this cathedral ceiling. Ceiling Remodel: From Flat to Cathedral — Opening up a flat ceiling in the family room of this ranch-style house transformed the space.

Is it better to separate the cathedral ceiling from the air flow?

Is it better practice to separate the cathedral ceiling insulation from the air flow with a permeable fireproof material such as drywall, leaving approximately 1/2 inch between the drywall and the bottom of the roof sheathing? — Larry Gunther, Neola, UT

Do you have to put R19 in cathedral ceiling?

The Town Building Department only requires I put in R19 in my upstairs vaulted (cathedral) ceiling since it is a remodel…. The flat portion is a different story and not really concerned about.

What kind of insulation does a cathedral ceiling need?

Here are some older home cathedral ceiling roof insulation and ventilation options that you may consider: Less insulation: Reduce under-roof insulation level to 3 ½” fiberglass (R-11) under the cathedral ceiling (not good energy savings) – not recommended but functional, just poor insulation value.