“Technical Paper 15 - Assessing risks in insulation retrofits using hygrothermal software tools - Heat and moisture transport in internally insulated stone walls” originally commissioned by Historic Scotland (a branch of the Scottish Government, now restructured as Historic Environment Scotland) was launched in September 21st 2015 in Dublin. It is intended to be a significant support to building professionals and building fabric consultants engaging with the topics of:
1) Applied building physics relevant to solid wall construction;
2) Hygrothermal risk assessment;
3) Appropriate internal insulation strategies for solid walls.
Technical Paper 15 has a number of original illustrations that should be of value in explaining heat and moisture transports and evaporative pumping (aka rising damp). It assesses various alternative internal insulation strategies from a number of perspectives using a specific test case building in Glasgow. The strategies are subjected to hygrothermal risk assessment under the two major methods (set out in BS EN ISO 13788 and BS EN 15026), as well as to thermal and biochemical assessment. It proves that different assessment methods have specific applications, are not inter-changeable and that the wrong method can give an utterly inaccurate understanding of hygrothermal risk. The glossary of Technical Paper 15 may prove useful for those wanting to understand building science terms, while the appendix includes a methodology for a useful simple way of measuring the amount and rate of moisture uptake from a surface (i.e. the Karsten Tube method).
The report is downloadable from
Its authors are Joseph Little of Building Life Consultancy (BLC), Beñat Arregi who worked with BLC for many years (returning to Spain in 2016), and talented services engineer Calina Ferraro from Canada (currently working in San Diego). Its issue was delayed by multiple re-writes, international releases of revised standards, rights of reply requests and a number of peer reviews. We like to think this was to the final benefit of the reader in allowing a deepening of knowledge and broadening of perspective and content. The authors were as interested in cultural forces that influence what Industry and guidance writers do, as they were in the technical standards, scientific mechanisms and boundary conditions present in the subject building fabric.
Building professionals often find pure building science daunting, while building scientists often miss the perspective of building professionals. In the process of being as accurate as possible about specific phenomena, and reporting these through peer-reviewed channels, scientists may not communicate using the language, methods and channels that building professionals need or expect. Increasingly the latter need support in the certification of compliance of building projects, where they have elevated hygrothermal risks (whether new build or retrofit), with the national building regulations. The reports need to be focused and clear: they also need to be supported by the author’s PI insurance if they are to have value in the chain of certification.
Going forward either existing consultancies (perhaps architectural technologists or services engineers) need to expand their remit to start providing independent, sober, standards-based hygrothermal risk assessments to the building industry, or a new breed of dedicated building fabric consultants (ideally combining on-site building pathology experience with desktop hygrothermal risk assessment tools) need to come into existence. When combined with a 2D and 3D thermal modelling service, the experience of Building Life Consultancy is that the assessor has (a) a powerful array of tools to gain an understanding of what is happening, or may happen, in a building (post-works), and (b) a potentially lucrative business. BLC developed its service, reputation and brand to such an extent that it had a larger market in the UK than in Ireland after some years, most of which was served remotely. Consultants take note!