Required R Value For Attic Insulation

This can happen if you add denser insulation on top of lighter insulation in an attic.

Required r value for attic insulation.

The table below shows what levels of insulation are cost effective for different climates and. The higher the r value the better the thermal performance of the insulation. In general to optimally isolate an attic on average an r value of the insulation is required ranging from r 50 to r 60. 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.

The homeowner could then check table 1 to find several choices. Typically current best home building practices indicate an r 30 to r 38 for attic insulation. The recommended r value for attic floor insulation for this house is r 38. Where you live different climates require different insulation r values.

Insulation level are specified by r value. If the existing attic floor insulation has an r 11 insulation value then an additional r 27 would be needed to bring the attic floor insulation up to the level recommended for that house. There are many ways to retrofit a home with fiberglass and. R value is a measure of insulation s ability to resist heat traveling through it.

Climate zone 1 consists of the following south florida counties. 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. If structural sheathing covers 40 or less of the exterior continuous insulation r value shall be permitted to be reduced by no more than r 3 in the locations where structural sheathing is used to maintain a consistent total sheathing thickness. Insulation which is compressed will not give you its full rated r value.

Recycled glass or sand that s melted and spun into fibers. Broward collier hendry lee miami dade monroe and palm beach and require a minimum r 30 attic insulation. 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. Your home s age if your home is more than 10 year old you likely need more insulation.

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. The further north northeast you go the colder it is and the more necessary r value will grow. You will need a higher r value of insulation if you live in the northeast than if you live in southern california. Recommended home insulation r values.

Achieving greater r values in exterior walls. You can achieve better thermal performance in your attic by adding an additional layer of insulation. 2015 code requires walls to be insulated with a minimum of r 20 or r 13 5 13 5 means r 13 cavity insulation plus r 5 insulated sheathing. What r value do i need.