Types of Spray Foam
A major factor regarding Spray foam cost is the type of spray foam you need. There are two main types: open cell foam and closed cell foam. Open cell foam is lighter, expands further, and is an excellent sound barrier, while closed cell foam is rigid and specializes as a thermal insulator.
Because of our climate RRSO only sprays closed cell foam. Open cell foam projects would be for special orders only.
Pricing for Closed Cell
Closed cell spray foam costs from $1.25 to $2.00 per board foot. A board foot is a square foot by 1 inch thick (Roughly R6.5 per inch) If you want R20 and your wall is 100 square ft you would need 300 board feet of foam (100sqft x 3inchs). The bigger the job the closer to $1.25 per board foot your price will probably be. Some projects with thousands of square ft will be priced even more aggresively.
If you want a square ft price simply mutiply the board foot price by the required thickness. Since we know the R-value is about R6.5 per inch and using the example above we require R20 - 3 inches. We'll mutiply $2.00 by 3 for a square ft price of $600 per square ft and a total price of $600 plus gst.
Some companies, RRSO included have a minium charge. Really small projects are just not worth doing on a per board foot basis even if we were to charge $5.00 per board ft. At RRSO we have a minum charge of $1200.00-$2000.00 depending on how busy we are. Winter months are usually less busy.