Ceiling Insulation Requirements

Existing 3 4 inches of insulation.

Ceiling insulation requirements. Friction fit insulation snugly between and parallel to all standard and narrow attic framing members. The minimum requirement is r30 as long as its properly installed over 100 of the ceiling and extending down over the top plate of the wall at the bottom. While federal and in some cases state guidelines for insulation levels are merely recommendations the local building code is the true authority over insulation requirements.

Ceilings pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1. Meet the fenestration requirements in table r402 1 2. However there is an exception.

The trick to this is that r30 requires a minimum cavity of 8 1 4. Just because insulation is labeled r30 does not mean it can be compressed into a cavity of smaller size. 1102 2 1 ceilings with attic spaces when section 1102 1 would require r 38 in the ceiling r 30 shall be deemed to satisfy the requirement for r 38 wherever the full height of uncompressed r 30 insulation extends over the wall top plate at the eaves.

Recommended insulation levels for retrofitting existing wood framed buildings. See the department of energy s doe ranges for recommended levels of insulation below. The 2015 irc requires r 49 insulation for ceilings with attic spaces.

R 38 shall be deemed to satisfy the requirement for r 49 wherever the full height of uncompressed r 38 insulation extends over the wall top plate at the eaves. Ensure insulation extends to the outside edge of the exterior top plates and is flush against any ventilation dams baffles. R 5 insulation shall be provided under the full slab area for heated slabs in addition to slab edge insulation r values.

Add insulation to attic. Depending on where you live and the part of your home you re insulating walls crawlspace attic etc you ll need a different r value. Typical recommendations for exterior walls are r 13 to r 23 while r 30 r 38 and r 49 are common for ceilings and attic spaces.