Fiber Cement Siding R Value

Half inch thick rigid foam insulation has an r value of r 2 to r 3 5.

Fiber cement siding r value.

Fiber cement siding doesn t add much insulation to your wall system measuring in at a mere r 0 50. Asbestos loose packed fibers powder. This beats fiber cement which has an r value of 5 at most. Because vinyl siding is thinner than fiber cement siding it can better accommodate insulation beneath its surface.

Adding inch of rigid foam insulation r 2 in this example will increase a 2x6 stud wall from an effective r 15 to an effective r 17. R value see table 2. If you choose fiber cement siding for your project then the r value of the product is only 0 5. While fiber cement siding is energy efficient vinyl siding has the potential for this too.

This is an increase of 13 of effective thermal resistance. According to table 5 1 of the ashrae fundamentals handbook fiber cement has an r value of 15 better than brick and stone but lower than vinyl at r 60 wood at r 81 and insulated vinyl siding at r 2 0 3 5. Esr 1844 noncombustibility see page 1 section 3 1 flame spread and smoke developed see page 1 section 3 1 1 hour fire walls see page 2 section 4 3 design wind loads see page 4 5 table 4 r values see page 3 table 2. Standard vinyl siding has an r value 6.

This means as a stand alone product fiber cement isn t going to add much insulation to your home. That s a little less than you ll get from vinyl siding which is rated as r 0 61 but the. When vinyl siding is optionally insulated it can achieve r 2 values and even greater. Asbestos cement shingle siding.

Underlayment material even a foam board doesn t offer much extra and would be applicable to both materials. For instance if you have a material with an r value of 12 attached to another material with an r value of 3 then both materials combined have an r value of 15. Foam thicker than a half inch will yield even higher r values. Most siding including fiber cement have an r value of less than 1 when installed alone with out additional layers or types of insulation.

Thermal conductivity k 0 15. Adding foam back vinyl siding leaves fiber cement in the dust as that has at minimum 1 8 r value. As we said before the r value measures the thermal resistance of a material. Asbestos lagging and paste will have a lower value.