R Value For Attics By Zone

Existing 3 4 inches of insulation.

R value for attics by zone.

You will need a higher r value of insulation if you live in the northeast than if you live in southern california. Whenever exterior siding is removed on an. Add insulation to attic. Most homes in the united states are not well insulated.

Department of energy only 20 percent of the houses built before 1980 are considered well insulated. We can see that sacramento and most of california are in zone 3 which requires attic insulation with an r value between 30 and 60. Why attic insulation r value matters for california homeowners at this point you may be wondering why this r value matters so much especially when it s for an attic that you probably go into once a year to fetch your christmas decorations. Existing 3 4 inches of insulation.

Existing attic 3 4 inches of insulation r 38. Floors r 25 to r 30. In fact according to the u s. Add insulation to attic.

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. Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. Many homes have no insulation at all because building codes didn t even require insulation prior to the mid 1970 s. Where you re installing it.

However there is an exception. Recommended insulation levels for retrofitting existing wood framed buildings. The 2015 irc requires r 49 insulation for ceilings with attic spaces. Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1.

Department of energy recommended r values for add insulation to attic zone 4 uninsulated attic attic insulation run between r 49 to r 60. Your home s age if your home is more than 10 year old you likely need more insulation. This zone has a recommended r value of 30 to 60 for an uninsulated attic r25 to r38 for an attic with existing insulation and r13 to r19 for the floor. There are many ways to retrofit a home with fiberglass and.

Average wall and roof u factor 0 200 in climate zones 1 5 and 0 120 in climate zones 6 8 comply with the roof solar reflectance and thermal emittance provisions for climate zone 1. Where you live different climates require different insulation r values. 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.