H1 Construction R-values for walls
In new edition of H1/AS1, the schedule method requires wall construction R-values to be R2.0 in all six new climate zones. The increased R-values apply under both the schedule and the calculation methods of determining H1 compliance.
How to achieve H1 construction R-value
If using the schedule method of compliance, the number in the H1/AS1 document is the minimum R2.0-value and this must be met or exceeded. However, if using the calculation method or the modelling / verification method it is possible to use a construction R-value which is lower than this number - provided this is offset elsewhere and that the designed home performs at least as well as a reference building. By using construction R-value which is higher than in the table, it provides the ability to use a lower R-value on other elements or to adapt the home elsewhere such as using lower cost windows, slab construction or using a higher glazing percentage to increase natural light to the home.
Considerations for H1 Compliance
It is worth noting that actual framing ratios should be taken into account, The H1 documents provides details on what needs to be included, but high timber ratios can make wall compliance in a 90mm frame a challenge.
It is possible to use a 45mm internal secondary layer to increase performance. For example, a simple 90mm frame with a R2.6 batt could achieve R2.0 construction value. By adding the additional layer R1.3 this could lift to R3.4 construction value.
Benefits of Knauf Insulation Solutions
Our wall insulation segments are designed for use in framed cavity applications between studwork, offering a range of thermal performance to meet evolving construction requirements. Knauf Insulation has a full range of R-values for R2.4 in a 90mm cavity and R4.4 in a 140mm cavity. The R1.3 45mm secondary layer provides flexibility for increased performance.
Earthwool Glasswool R1.3 Wall Insulation Batt is specifically designed to meet H1 Building Code changes. The R1.3 45mm secondary layer provides flexibility for increased performance.
Earthwool Glasswool R4.4 Wall Insulation Batt is specifically designed to meet H1 Building Code changes.