If you are building a new home and heading towards the insulation portion of your project, it will be very daunting to know that prescriptive or dictated R value requirements to meet code have gone up once again. The R values required in our region are now R60 in attics, R30 for exterior walls, and R 30 for basement/garage ceilings. Following these scheduled bar values requires the following amount of spray foam to meet this new code:
Attic/rafter – 8.5 inches closed cell, or 16 inches open cell
Walls - 4.5 inches closed cell.
Basement or garage ceilings – 4.5 inches closed cell, or 8 inches open cell
A spray foam installation with these thicknesses of application cost and outrageous fortune. What makes matters worse is that in meeting code in this fashion nearly half of the installed spray foam doesn't even increase the performance of the thermal envelope as can be seen in the conductive flow chart below of spray foam performance by inch thick apply.
This is why we, at Black Bear Spray Foam, have utilized and continue to utilize the prescriptive section of the code which allows for engineering and calculating a specific homes thermal envelope with its mechanical systems. When we can show that we exceed the performance of the above stated R values with traditional insulation materials (fiberglass, mineral wool, cellulose) with high performance insulation (Spray Foam) by 30%. Once the calculation reaches 30%, that it is the only amount of spray foam required to be installed in your home. This is the prescriptive or performance-based approach to meeting the code. This method typically results in the following/below amount of foam being required which is significantly reduced from the above numbers which in the average size home can save customers anywhere between 5,000.00 and as high as $20,000 for an installation without losing any performance of the system.
Attic/rafter – 3-4 inches closed cell, or 6-8 inches open cell.
Walls – 2 inches closed cell.
Basement or garage ceilings – 2.5 inches closed cell, or 4 inches open cell.
The total foam thickness reduction as can be seen below in the charts is only eliminating the foam that is achieving less than 1-2% of performance increase per inch resulting in thousands of dollars of real saved money to our customers.
More technical information: When our reports indicates that your project meets the 2021 IECC-CT standard
International Energy Conservation Code, 2018 Edition: Developed and published by the International Codes Council, the IECC‐2018 “establishes minimum regulations for energy efficient buildings using prescriptive and performance‐related provisions. This code is founded on principals intended to establish provisions consistent with the scope of an energy conservation code that adequately conserves energy; provisions that do not unnecessarily increase construction costs; provisions that do not restrict the use of new materials, products or methods of construction; and provisions that do not give preferential treatment to particular types or classes of materials, products or methods of construction.”
Summary:
By utilizing Black Bears Home energy modeling performance based approach we meet and exceed code with R-values that are substantially lower than the prescriptive approach. In Fact, The REM program will typically show that a Spray foam house at the lower R-values will outperform the prescriptive home by 30-50%.