Attic R Factor In Nc

Recommended insulation levels for retrofitting existing wood framed buildings.

Attic r factor in nc. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. 10 13 means r 10 continuous insulated sheathing on the interior or exterior of the home or r 13 cavity insulation at the interior of the. 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. R 19 on floor system garage ceiling.

Notes from previous r value chart a. Add insulation to attic. Adding insulation in your home s attic can help control utility bills. Wake county is 4a zone so walls floors ceilings and slab insulation values are unchanged from the 2012 code.

R 38 for the ceiling attic. Recommended insulation levels for retrofitting existing wood framed buildings. Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces. This can happen if you add denser insulation on top of lighter insulation in an attic.

It also happens if you place batts rated for one thickness into a thinner cavity such as placing r 19 insulation rated for 6 1 4 inches into a 5 1 2 inch wall cavity. Insulation which is compressed will not give you its full rated r value. U factors and shgc are maximums. Houses in a cold climate should have a minimum of r 49 in the attic which is equivalent to approximately 16 of fiberglass insulation.

Heating and cooling costs continue to rise. The map below shows the most cost effective levels of insulation for the different climate zones in the u s. The fenestration u factor column excludes skylights. Walls need to be insulated to a minimum of r 20 if the insulation is between the studs or r 15 r 5 if the insulation is a combination of insulation between the studs and a continuous layer of exterior insulation in zones 3 or 4.

If you think you re among the 90 of us homes that are under insulated 1 performing a simple insulation inspection will help you determine your insulation needs. Based on your zone use the table to find out how much insulation you need to add if you. The prescriptive r values for a new house in the new 2018 nc building code are as follows. Existing 3 4 inches of insulation.

R 15 on exterior walls. Roofs or ceilings need to be insulated to a minimum of r 38 in zone 3 or r 49 in zone 4. Warmer climates only require an r 38 or higher or about 12 or more.