Required R Value For Attic Insulation

The homeowner could then check table 1 to find several choices.

Required r value for attic insulation.

However there is an exception. Recycled glass or sand that s melted and spun into fibers. 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. 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.

However there is an exception. R 5 shall be added to the required slab edge r values for heated slabs. Existing 3 4 inches of insulation. 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.

You will need a higher r value of insulation if you live in the northeast than if you live in southern california. Special insulation exceptions related to ceilings with attic spaces ceilings without attic spaces masonry veneer and thermally isolated sunrooms are set forth in iecc. The higher the r value the better the thermal performance of the insulation. Achieving greater r values in exterior walls.

Where you live different climates require different insulation r values. Recommended insulation levels for retrofitting existing wood framed buildings. Does your home have enough r value. You can achieve better thermal performance in your attic by adding an additional layer of insulation.

Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1. Your home s age if your home is more than 10 year old you likely need more insulation. With an r value of 4 0 to 5 1 per inch depending on the manufacturer pre expanded injection foam provides a higher r value than fiberglass or cellulose and it seals the building from air leakage at the same time. The recommended r value for attic floor insulation for this house is r 38.

This can happen if you add denser insulation on top of lighter insulation in an attic. There are many ways to retrofit a home with fiberglass and. Most homes in the united states are not well insulated. Add insulation to attic.

Lighter in weight than cellulose or mineral wool but it settles more than those materials so you ve got to put in a thicker layer to get the protection you need. Insulation requirements for slab on grade floors is further specified in iecc section 402 2 8.