Guide to external insulation

A new feature in Passive House Plus, the “Guide to…” series in intended as a reference source that the industry will long refer back to – which will also extend the lifespan of each issue and the impact for advertisers.

The Guide to External Insulation will include:

• historical context – external insulation is not as new as people may think;
• an explanation of why well-detailed external insulation systems are such an attractive option – a simple, robust, buildable approach that keeps the structure warm, dry and healthy;
• why stringent current and imminent building regulation requirements on insulation and thermal bridging are making external insulation increasingly attractive – including the forthcoming nearly zero energy building targets for all buildings – new build and major renovations, dwellings and non-domestic buildings;
• an overview of the range of materials available (insulation types, adhesive vs mechanical fixings, silicone versus mineral render systems, brick slips etc);
• advice on detailing at critical areas (below DPC, window reveals, eaves, utility boxes, gutters, etc) to avoid thermal bridging, and to keep the system weather-proof; suggested maximum U-values – subject to restrictions on existing buildings in some instances;
• the importance of allowing for contraction & expansion & building movement;
• the connection between external insulation & different wall types - be it various kinds of single leaf masonry, steel frame or timber frame, including variation in detailing;
• an explanation that insulation thickness – and potentially overall wall thickness – can be reduced if the structure offers a good thermal conductivity too. Such as with thermal blocks (in particular AAC blocks or poroton blocks);
• consumer protection. An explanation of what quality assurances are on offer – ranging from latent defect insurance, to guarantees/warrantees on materials and labour.
• The critical role of installer competency.
• Material sustainability. While we’re still in the dark ages on lifecycle analysis in general, that is changing. EPDs on systems are a start. And a note that LCA should take account of the fact that robust fabric-first approaches such as external insulation will continue saving energy for decades after high tech energy saving solutions have reached their end of life.
• information on durability – including a discussion of whether the approach certain certification bodies take to make 60 year durability statements is credible or helpful;
• fire safety (including fire break detailing in multi-storey buildings);
• Cost and value. Why the marginal cost of installing, say 200mm instead of 100mm is often remarkably low. Any why a system that can improve not just the comfort levels and energy performance, but the external appearance of existing buildings, may boost the property price.

The article will draw from the advice of independent experts in low energy building with experience of external insulation, along with technical spokespeople from relevant associations and certification bodies.

The online version of the article will link to an exclusive gallery of construction details of external insulation systems. Advertisers will be able to submit a limited number of details for this gallery, provided they meet our formatting requirements.