Roof R Value Code

For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3.

Roof r value code.

Both codes provide specific instructions for re roofing projects and both are clear that replacements must comply with insulation r value requirements if the roof system is part of the building thermal envelope and contains insulation entirely above the deck. State applicable code ashrae zone 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. Always check with your local code authority. These energy code r value requirements change from state to state and even city to city.

For example two inches of extruded polystyrene with an r value of 11 has an rsi of 1 93721. 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. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. R value is a measure of insulation s ability to resist heat traveling through it.

Code official finds proposed design is satisfactory and complies. The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. R value based method of section c402 1 3 u c and f factor based method of section c402 1 4. Recommended home insulation r values.

Average wall and roof u factor 0 200 in climate zones. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. To convert rsi to r value multiply the rsi by 5 67826. Existing buildings requirements are sprinkled throughout the i codes.

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. Please note that the r values for roof membranes shingles tiles air films and roof deck materials might or might not be permitted by your local code to be included when total roof assembly r value is being calculated for the purpose of satisfying energy code requirements. Insulation level are specified by r value. 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 higher the r value the better the thermal performance of the insulation.