Polyurethane Foam R Value

During the 1970s in idaho s snake river valley my firm insulated the walls of many new homes with 1 25 inches of spray in place polyurethane foam.

Polyurethane foam r value. A foams r value is its resistance to heat flow or in other words how well they insulate. The r value of closed cell foam is r 6 5 7 per inch. By expanding 100 times its original size icynene seals cracks and gaps in attics walls ceilings and other spaces where air might escape. Open cell spray foam typically has an r value of 3 5 per inch and it should be noted that open cell does not form a tight air seal.

This product typically has an r value of 3 6 to 4 0 per inch of thickness. However fiberglass generally does not provide as tight a seal as a foam product would since it is unable to achieve as tight of a seal. An r value tells you how well a type of insulation can keep heat from leaving or entering your home. Insulation r values vary based on the type thickness and density of the insulation material.

In comparison glass wool typically has an r value of only r 3 to r 4 per inch. Typically a higher insulation r rating means better climate control and better energy efficiency for your home. Polyurethane is a closed cell foam insulation material that initially contains a low conductivity gas in its cells. The r value of a material is of no interest or consequence if air can get past it.

It performs better than other insulation types. Closed cell foam has a higher r value than open cell foam usually about 6 0 per inch. In 1970 the popular number for the r value of one inch of urethane foam was 9 09 per inch. It performs much better than any form of batt for stopping air flow but it is not as complete of an air seal as closed cell spray foam.

Expanded polystyrene insulation is similar to the foam used for packing peanuts and it s typically used for insulated concrete forms also knows as icf s. Additional r value for a masonry wall constructed using these materials needs to add the insulating value of additional wall components typically included such as 1 solid foam polyisocyanurate r 8 extruded polystyrene r 5 expanded polystyrene r 4 or 1 of perlite r 2 7 and for an exterior air film winter no wind r 0 17 an interior. Contractors often use it to insulate under slabs ceilings walls and roofs. This r value is similar to that of r13 fiberglass batting.

Expanded polystyrene foam eps is the cheapest and least used foam board product on the market. Icynene sprayed in foam is an insulation and air seal system that works to help ensure that your home doesn t suffer from air loss while providing an effective r value. A typical 2 4 stud filled with open cell spray foam will have an r value between 10 5 and 14.