Home Improvement--General/insulation


Dear TB,
  I have an old house and want to insulate the roof rafters to finish my attic. The problem is that most rafters are spaced at 26 +/- 1 inches leaving a nonstandard gap between them. Can I still use fiberglass batts? Recommendations? Sincerely, Dick Schlueter


Check to make sure you didn't just measure the one or several locations that are non-standard.

If you are going to insulate the existing rafters of an attic be aware of the needed air movement requirements between the roof sheathing and insulation product you choose. That includes outside air ventilation at the high and low points.

Ceiling insulation is usually on the order of R-30 which is very thick.
Will you be able to install that with air space without furring down from the existing rafters?

If you fur down install the furring at 24" OC and use that to attach your insulation to.

If you have the space you can painstakingly slit fiberglass batts to fit around the rafters and run them horizontally.

You could just cut batts to 27" (?) lengths and install them one square at a time.

I think the final option will end up being a rigid board instead of batts that you can cut and wedge to fit though I think slitting batts will look easy after you have started doing that.

Home Improvement--General

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Thomas Buford


Licensed Architect in Virginia since 1984.
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