R Value For Attics By Zone

Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation.

R value for attics by zone.

Your home s age if your home is more than 10 year old you likely need more insulation. The 2015 irc requires r 49 insulation for ceilings with attic spaces. Walls should be between r 19 to r 21 basement walls r13 to r 19. However there is an exception.

Department of energy recommended r values for add insulation to attic zone 4 uninsulated attic attic insulation run between r 49 to r 60. Existing 3 4 inches of insulation. Most homes in the united states are not well insulated. Floors r 25 to r 30.

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. Existing attic 3 4 inches of insulation r 38. Each state does have their own minimum insulation requirements which are often lower than the levels recommended by the department of energy.

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. Add insulation to attic. Recommended insulation levels for retrofitting existing wood framed buildings. In fact according to the u s.

Department of energy only 20 percent of the houses built before 1980 are considered well insulated. You will need a higher r value of insulation if you live in the northeast than if you live in southern california. Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1. Whenever exterior siding is removed on an.

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. Add insulation to attic. 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.

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.