Polystyrene Insulation R Value Per Inch

Because rigid foam plastic insulation products are not all aged in accordance with the same standards it is useful to publish comparison r value data.

Polystyrene insulation r value per inch.

It provides r values that range from 3 6 to 4 2 per inch. The thermal conductivity k of a material is expressed as the rate of heat flow in british thermal units per hour. Products with a higher r value have a higher cost but have an increased capacity to resist heat flow and therefore provide greater insulation. 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.

It also is the least expensive. Eps is suitable for ground contact and can be treated to resist. Eps has the lowest average r value of the three most common types of rigid foam insulation around r 4 per inch. For instance if the specified insulation has an r factor of 3 8 and you are using 3 5 inches of insulation the r value is 13 3.

Expanded polystyrene eps eps is the insulation used most widely in insulated concrete forms and structural insulated panels sips. The time of testing. R value then is the r factor of an insulation material multiplied by the amount of material used. The r value for foamular xps insulation is provided from testing at two mean temperatures 40ºf and 75ºf and from two aging conditioning techniques 180 day real.

Also called styrofoam insulation this is the least expensive material. Expanded polystyrene made from expanded foam beads that are molded into shape expanded polystyrene or eps is ideal for above grade applications such as exterior walls and offers an r value of 3 6 to 4 2 per inch. Expanded polystyrene foam eps is the cheapest and least used foam board product on the market. Material costs are about 0 31 per square foot for each inch of thickness plus installation costs.

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. Falls in the middle of the three types of rigid foam insulation in both cost and r value used most in walls or below grade applications recyclable and at about r 5 per inch costs around 42 per sq. Each type comes with unique advantages. For a 1 in thick 4 8 panel comes unfaced or with a number of different plastic facings.