External Solid Wall Insulation Thermal Bridges Executive Summary G#9255

By January 15, 2016Code, Encyclopaedia, Issues

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External Solid Wall Insulation Thermal Bridges Executive Summary

External Solid Wall Insulation Thermal Bridges Executive Summary:


From Fuel Poverty to Respiratory Distress – Energy Company Obligations (ECO) is it going wrong?

Executive summery:

External Solid Wall Insulation (ESWI) and Internal Solid Wall Insulation (ISWI) often optimized for new-build is also being applied to old stock solid wall houses. These ESWI and ISWI do not have readymade solutions for dealing with existing external or internal services, other abutments and window reveals. The simple solution to these details is to stop and start the ESWI either side of the services and other abutments. But this is highly risky and the wrong result is inevitable unless purposeful ventilation is also installed.

Highly insulated and weather protected walls side by side with strips of un-insulated unprotected wall will result in problems. Concentrated weather saturation leading to moisture penetration will occur in the exposed strips. There is a very high risk of wall saturation leading to embedded structural timbers rising in moisture content leading to rot and structural failure. Saturated brickwork may also suffer from frost damage at the external surface in freezing conditions.

Warm moisture vapour from bathing, laundry and cooking inside the house will also find its way outwards through the line of least resistance. The colder inside face of the un-insulated strips of wall run the risk of cooling internal humid air and causing surface condensation. Spores from fungi are ever present in the atmosphere, wind blown ‘seeds’ waiting to grow. When spores land on any surfaces, if the surfaces are wet the spores can and do start growing, they increase to become mould that grows and spreads and generates more spores. Moulds and spores in the air can cause respiratory disorders and asthma in the young, unwell, older and frail people. In the worst cases toxic mould can cause death; forcing buildings along with all possessions to be abandoned and sealed up.

Un-insulated strips between insulation and service can be solved. One company in particular Enviroform Solutions Ltd. has focused on developing solutions for many of them: Window/Door Jambs Reveals; Eaves Fascia & Gutter, Ground level abutment, Soil Waste and Vent Pipes, Rainwater downpipes, Internal electrical junction and surface boxes. These solutions have been developed to be simple, practical and economical. The effectiveness and competency have been independently evaluated and documented. They solve this highly risky and inevitable problem. There is little excuse not to use them.

These products have been brought to the attention of Main Contractors, ESWI system designers, to Energy Company Obligation (ECO) obliged businesses and GreenDeal (GD) Providers. They have seen the merits of them and have sometimes engaged Enviroform Solutions Ltd. in tenders for large-scale projects. 53,000 ECO projects out of a total 200,000 ESWI projects have been carried out in 3 years since October 2012. A significant percentage are Victorian and CI pipes can be expected in most of them. When these contracts have been awarded the solutions seemed to have been removed from the scheme. With very few being actually installed, possibly due to budgetary constraints and trying to make projects commercially viable. The issue here is that the main contractor is getting paid per house not by performance. The short term gain is usually followed up by a long term legacy of continuing maintenance problems.

They are not being held accountable to the specifications or standards or even the Publicly Available Standard (PAS 2030) developed to drive competency in ECO and GD. Nor are the specifications addressing the real details. They are often written as ‘system specification’ missing out ‘detail specification’. National Building Specification (NBS) used by many specifiers, has work section M21 for External Insulation with Rendered Finish. M21 is for new-build and refurbishment, but fails to address the details associated with existing services. Many specifiers are worried to embellish or divert from the NBS standard text in fear for their Professional Indemnity Insurance (PII) cover, but this leads to greater risk.

Green Building Specification (GBS) has just developed specifications for the Enviroform Solution Ltd. This includes the Thermo-Pro® system, all of the Thermo-Pro® BeadSoilFlashFasciaTrac accessories designed to be installed before and together with a competent ESWI system to make a competent refurbishment ESWI system for buildings with external services. GBS Specification M21 for External Insulation with Rendered Finish Work Section, Clauses and GBE Checklist M21.

GBE have warned in many seminars, GreenDeal/ECO will be followed by a second programme to correct the errors of GreenDeal/ECO on much of the existing solid walled housing stock gone wrong. Use these solutions or their equivalents’ (not ‘or similar’) like these or risk failure.


© GBE GBS NGS ASWS Brian Murphy aka BrianSpecMan
6th January 2016 – 22nd January 2016

External Solid Wall Insulation Thermal Bridges Executive Summary:
See Also:


GBE ESWITB Navigation

  • G#9244 GBE Issue: External Solid Wall Insulation and Thermal Bridges
  • G#        GBE Issue: ESWITB Navigation
  • G#        GBE Issue Paper: ESWITB (xx A4 pages as a continuous page) alternatively:
  • G#9255 GBE Issue Paper: ESWITB: Executive Summary (This page)
  • G#        GBE Issue Paper: ESWITB: Contents List
  • G#        GBE Issue Paper: ESWITB: Introduction
  • G#        GBE Issue Paper: ESWITB: Chain of Topics (many sub-topics linked as a chain)
  • G#        GBE Issue Paper: ESWITB: Case Studies
  • G#        GBE Issue Paper: ESWITB: List of Solutions
  • G#        GBE Issue Paper: ESWITB: Jargon Buster
  • G#        GBE Issue Paper: ESWITB: Revision table

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G#8288 Rendering system on existing insulated cavity wall

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© GBE NGS ASWS BrianSpecMan aka Brian Murphy
15th January 2016 – 22nd January 2016

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