Recommended Wall Insulation Values

Foam plastic insulation on the interior of the building envelope must adhere to the requirements of protection of foamed plastics as per 9 10 17 10 of the national building code of canada.

Recommended wall insulation values.

For example insulation that is compressed will not provide its full rated r value. Achieving greater r values in attics. While rated differently these two types of insulation are close enough in thickness that they can both fit into modern two by four wall systems. In most wall applications you will use r 13 or r 15 kraft faced fiberglass insulation rolls for these two by four stud walls.

R value is a measure of insulation s ability to resist heat traveling through it. Recommended home insulation r values. Typical recommendations for exterior walls are r 13 to r 23 while r 30 r 38 and r 49 are common for ceilings and attic spaces. The following 2008 department of energy zone recommendations are based on comparing estimated future energy savings to the current cost of installing insulation.

Department of energy r value recommendations for new and existing homes. Along with knowing the r value of a particular insulation it is also important to calculate the r value of a total system. While wall insulation is limited by the width of the studs different materials provide higher or lower r values. The overall r value of a wall or ceiling will be somewhat different from the r value of the insulation itself because heat flows more readily through studs joists and other building materials in a phenomenon known as thermal bridging.

The insulation must be water resistant and be continuous from the adjacent finished ground level to a depth of 300mm or for at least the full depth of the vertical edge of the concrete slab on ground. Fiberglass batts for standard 2 4 walls are now available in low medium and high density products that range from r 11 to r 15. In such cases where r value is assigned this may decrease the r value requirement for batt insulation. Insulation level are specified by r value.

The insulation must achieve a minimum r value of 1 0 in zones 1 to 7 and a minimum r value of 2 0 in zone 8. For example a wall with 3 fiberglass batting r value of 10 8 11 9 may have an overall r value of nearly 14 because of siding sheathing and drywall. The ideal attic insulation r value is different than the ideal wall insulation r value. See the department of energy s doe ranges for recommended levels of insulation below.

Insulation ratings can be improved by adding more layers of insulation. Make sure your home is properly insulated in all these locations.