Specification J1.6 Sub-floor thermal performance
To provide the R-Values considered to be achieved by sub-floor spaces and soil in direct contact with a floor.
The R-Values provided are intended to assist in determining whether and how much additional insulation is required to achieve the minimum Total R-Values in Table J1.6. This is provided as an alternative to carrying out a more detailed calculation using Section 3.5 of CIBSE Guide A.
2. Sub-floor thermal performance
Table 2a details the R-Values considered to be achieved by enclosed sub-floor spaces that are—
mechanically ventilated by not more than 1.5 air changes per hour; or
|Ratio of floor area to floor perimeter (m)||Sub-floor space R-Value|
Note to Table 2a
Note to Table 2aWhere the ratio of floor area to floor perimeter is between the values stated, interpolation may be used to determine the sub-floor space R-Values.
Table 2b details the R-Values considered to be achieved by the soil for floors that are in direct contact with the ground.
|Ratio of floor area to floor perimeter (m)||Wall thickness of 50 mm||Wall thickness of 100 mm||Wall thickness of 150 mm||Wall thickness of 200 mm||Wall thickness of 250 mm||Wall thickness of 300 mm|
Note to Table 2b
Note to Table 2bWhere a wall thickness or ratio of floor area to floor perimeter is between the values stated, interpolation may be used to determine the soil R-Value.
To detail the thermal performance achieved by sub-floor spaces and soil in direct contact with a floor.