This third post on the basics of Thermal Modelling and Building Regulation compliance and explains how Thermal Bridging is handled as part of the Passivhaus certification.

This FACT SHEET outlines the fundamentals of Passivhaus Thermal Bridge terminology and calculations. It is important to see how the critical details in a project are certified by the Passivhaus Certifier:

Part of the information required by the Passivhaus Certifier are:

• 1:10 & 1:5 details of all junctions

• Conductivity value certificates with CE marks

• Photographic evidence on these details showing how the thermal bridges were managed

• Thermal bridge calculations where the details are not ‘thermal-bridge-free’

This information should ideally be checked at pre-planning, pre-build and on completion. In Ireland under S.I No.9 of 2014 it would be the ‘Designer’ who takes responsibility for the detailing and drawing of the junctions and the Assigned Certifier who would take responsibility for the specification/construction of the same materials and junctions. As an authorised ‘Designer’ and ‘Assigned Certifier’ under S.I No.9 of 2014 (as a registered RIAI Architect) AND a Certified Passivhaus Designer, I am ideally placed to design, detail and manage the construction of such Passivhaus details.

The ideal scenario therefore is to use Passivhaus details that are deemed ‘thermal-bridge-free’ throughout and your Passivhaus Designer (ahem) can advise you of these. Should a detail be deemed not to be ‘thermal-bridge-free’ you can use software such as THERM or Psi-Therm or a specialist consultancy to calculate them for you.

Target-Zero (the Passivhaus training company & consultancy) have an excellent set of details in the DOWNLOADS section of their website.

It should be noted that any ‘non-standard’ details; ie those not covered by the Part L Acceptable Construction Details or Appendix D of Part L require third party certification from a body such as Agrément or equivalent or certified by a member of an approved thermal modellers scheme or equivalent. Currently as we’ve seen there is only one approved thermal modeller consultancy in Ireland (Passivate) and it would be interesting to know whether certified Passivhaus ‘thermal-bridge-free’ details meet the requirements of ‘Agrément or equivalent’? Anyone know?

Comments welcome…