I propose to take Questions Nos. 166 to 168, inclusive, together.
I refer to the reply to Question No. 788 of 15 April 2015 which addressed the approach to calculating the temperature factor in the vicinity of thermal bridges at junctions and around openings in accordance with Appendix D of Technical Guidance Document L 2011. The surface resistance values given in IS EN ISO 13788 are consistent with those given in the Building Research Establishment Report BR 443 Conventions for U-Value calculations (2006 edition) for such details. A surface resistance value of 0.25 is only used in very specific situations as outlined in section 4.4 of the EN ISO 13788 standard which is of rather limited relevance in this context and, for that reason, it has not been referenced at Appendix D of TGD L 2011 or referred to in the reply to Question No. 788 of 15 April 2015. I.S. EN ISO 13788 is referenced elsewhere in TGD L 2011 - in relation to Appendix B, which provides additional guidance on fabric insulation for common constructions, in particular - and it may be relied upon to the extent to which it has relevance to the matters raised in TGD L. My Department is willing to assist further in relation to this matter by way of correspondence or meeting as appropriate. A dedicated email account - buildingstandards@environ.ie – is in place to facilitate such requests.