Due to the nature of spray foam or blown insulation and other materials used, Stellrr is unable to guarantee the exact output. Sprayed or blown insulation does not apply to exact depths, this is neither a defect in materials or workmanship.
All R-Values/Thickness depths in quoted/contracted are Averages (nominal fill), not minimum. The nominal thickness is plus or minus 1-inch.
If 90% of the project meets the nominal thickness, then it is considered within the approved specifications. If some areas have significantly more than the nominal thickness installed, other areas may have considerably less thickness, and this is appropriate.
Do not be concerned if depths of foam vary greatly. The depth of the foam is less of a concern than with other products.
The performance of the building will be minimally impacted by the depth, as the biggest benefit of foam is the air infiltration sealing ability.
The ultimate determination of how much foam was installed will be determined as follows:
The manufacturer’s specifications state how many board feet (1 sq ft area, 1 in thick) are made out of each gallon of materials.
The material installed is measured by the Graco Proportioner computer which pumps out the material and is the brains of the foam rig.
Stellrr will installs the correct number of gallons/pounds of material. If the project requires more gallons than included in the estimate, Stellrr will consult the client about making a change order to add more materials, and achieve the clients goal.
Stellrr sells and installs foam, ultimately by the gallon/pounds, according to the manufacturer’s coverage and yield Technical Data Sheets.
Open Cell Foam is called 0.5 pound foam because at the stated R-value per inch (R3.6 – R4.0), it will weigh .5 pounds per cubic foot. A cubic foot is 12 board feet (12”-wide x 12”-deep x 1”-thick). So a bd ft of open cell foam would weigh .04166 pounds each.
Closed Cell Foam is called 2.0 pound foam because at the stated R-value per inch (R6.4 – R7.1, it will weigh 2.0 pounds per cubic foot. A cubic foot is 12 board feet (12”-wide x 12”-deep x 1”-thick). So a bd ft of open cell foam would weigh .16666 pounds each.
Two 55 gallon drums of foam is called a Set. The weight of material in the drums is 500lbs and is 50 gallons. So spraying a set of material is 1,000 pounds being installed.
Here is the formula for calculating 1,000 pounds of foam installed equals:
- Open Cell 1,000lbs / 0.5lbs per cubic ft x 12bd ft per cubic ft = 24,000 bd ft per set or 240 bd ft per gallon.
- Closed Cell: 1,000lbs / 2lbs per cubic ft x 12bd ft per cubic ft = 6,000 bd ft per set or 60 bd ft per gallon.
Stellrr ultimately sells foam to the Client by the pounds/gallons installed.
We can accurately measure the number of gallons installed on your project. We cannot measure how many inches are hard to account for because of metal corrugations, wrapping around rafters, filling hidden cavities, and much more.
Our costs to to do your project are tied up in the materials installed. We will install the correct number of pounds of material over the estimated sq footage. We cannot guarantee the depth of the foam. If you desire more depth, we are happy to continue to sell it to you by the pound / gallon of material installed.