Minimum R Values For Roof And Walls

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Minimum r values for roof and walls.

R value measures how well certain building insulation materials can resist heat. The higher the r value the better the thermal performance of the insulation. Basement walls require a minimum of either r 10 continuous or r 13 batted insulation. See the department of energy s doe ranges for recommended levels of insulation below.

You should of course see the manufacturer provided technical data sheet for the r value of specific products. R value is a measure of insulation s ability to resist heat traveling through it. Below is a table outlining the basic r value requirements for walls roofs and floors. Roofs or ceilings need to be insulated to a minimum of r 38 in zone 3 or r 49 in zone 4.

Recommended home insulation r values. R value of various materials. 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. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials.

Required r values for walls roofs and floors. The higher the r value the greater the insulation performance. Minimum r value state local al alabama 2015 alabama commercial energy code 2 r 25 3 r 25 state local ak alaska 2012 alaska building energy efficiency standard 7 r 35 8 r 35. Insulation level are specified by r value.

When determining how much insulation you need don t guesstimate calculate. State applicable energy ashrae zone minimum r value state local ms mississippi ashrae 90 1 2010 2 r 20 3 r 20 state local mo missouri 2012 iecc. 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. Note that there are many other requirements and exceptions to these figures depending on the state type of home and materials your home uses.

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.