Roof Insulation R Value Code

While the r value for a material is typically given per inch the rsi is typically given per millimeter so please be aware that the r values and rsi values for the materials in the following table are not for equivalent thicknesses.

Roof insulation r value code.

State applicable energy ashrae zone. R value is a measure of insulation s ability to resist heat traveling through it. 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. R value measures how well certain building insulation materials can resist heat.

In addition the common belief that an average r value is just as good as the code requirements is just that a common belief not a fact. Types of roof insulation. The table below shows what levels of insulation are cost effective for different climates and. Building and energy codes almost always specify a required minimum r value for exterior walls and roof assemblies with above deck insulation so the minimum required r value in your local jurisdiction is something that you need to take into account when planning a building project.

Minimum insulation r value requirements non residential above roof deck. 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 level are specified by r value. Tapered insulation is the most common method for creating a slope on a low slope roof but frustratingly neither code addresses compliance for tapered systems.

These energy code r value requirements change from state to state and even city to city. When determining how much insulation you need don t guesstimate calculate. State applicable code ashrae zone minimum r value state local al alabama 2015 alabama commercial energy code 2 r 25 3 r 25 state. 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.

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. Know exactly how much you need with our project calculators. The higher the r value the better the thermal performance of the insulation. The higher the r value the greater the insulation performance.

Minimum r value non residential above roof deck 19727 57th avenue east puyallup wa 98387.