M21 Insulation With Rendered Finish Checklist

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GBE Checklist: M21 Insulation With Rendered Finish (CL)

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GBE Checklist: M21 Insulation With Rendered Finish
Problems/Solutions:

Issues:

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.
See Solutions and Problems below
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.

Problems:

Energy Company Obligation (ECO) funding may be inadequate for the job, shortcuts are being taken and insulation is being stopped and started around external exposed service pipes on solid external walls.
Leading to condensation, mould and in time ill health, respiratory distress, asthma and at worst death.
The products listed below 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.

Misunderstandings:

‘or similar ’ does not equal ‘or equivalent‘

Solutions:

Thermal break/weather protection/edge protection beside and behind all exposed external services interrupting insulated render

Some years ago Enviroform Solutions Ltd. had solved the window jamb/reveal thermal bridge problems with Solid Wall Internal Insulation Systems and Solid Wall External Insulation systems. GBE discovered that Enviroform’s Liam Brown has been very busy inventing and developing solutions to many of the recurring problems with these systems. Un-insulated strips between external insulation and external services have now been solved. Enviroform Solutions Ltd. has solutions for many of them:
- System: Thermo-Pro®
- Window/Door Jambs: Thermo-Pro Bead
- Eaves Fascia & Gutter: Thermo-Pro Fascia
- Ground level abutment: Thermo-Trac
- Soil Waste and Vent Pipes: Thermo-Pro Soil Pipe
- Fence and gates: Thermo-Pro Soil Pipe
- Other service attachments: Thermo-Pro Soil Pipe
- Realigned Rainwater downpipes: Thermo-Pro RWP
- Roof abutment flashings: Thermo Flash
- Window wall posts: Thermo-Pro Steel Box
- Internal Window/Door Reveals: Magnaline Reveal
- DIY Internal Window/Door Reveals: DIY Thermal Reveal Kit
- Internal electrical junction and surface boxes: Thermo-Soc
- Internal Joisted floor/External wall: Thermo-Joist
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.

GBE Checklist: M21 Insulation With Rendered Finish
Consider/Avoid:

Consider:

Thermal break/weather protection/edge protection beside and behind all exposed external services.
External insulated building make the most of the external wall’s thermal mass to hold solar gained heat and store it to release later when the sun has set; thus regulating the temperatures inside whilst external temperatures fluctuate.
This can be exploited in Passive, Zero Energy Developments, Solar Designed Buildings,
Lightweight timber buildings cannot do this as well but the use of the right surface and thermal insulation materials can achieve equivalent results.
Cellulose fibre insulation
Mineral based render
Mineral based finishes

Substitute:

Minimise:

Avoid:

Thermal bridges through insulation on solid external walls with exposed external service pipes; insulate behind the services
Plastic based renders, static electrical charge attracts dust and dirt will look mucky and will need maintenance sooner on appearance grounds
Plastic thermal insulation See P10 & Z50
PVC edge beading See M21 & Z50
Virgin plastics See Z50

GBE Checklist: M21 Insulation With Rendered Finish
Health/Environmental

Health:

Upon further investigation it turns out this type of ‘Stop-Start Solution’ can be seen everywhere. In these cases highly insulated/weather protected walls and strips of un-insulated/unprotected wall will result in problems:

Concentrated weather saturation leading to moisture penetration will occur in the exposed strips:
- Wall saturation leads to rot in embedded structural timbers and structural failure
- Saturated brickwork can suffer from frost damage in freezing conditions
Warm moisture vapour from bathing, laundry and cooking inside the house will find its way outwards through the line of least resistance:
- Un-insulated strips of wall will be colder inside than surrounding insulated wall
- This runs the risk of causing surface condensation
- Spores from fungi are ever-present in the atmosphere, wind blown ‘seeds’ waiting to grow
- When spores land on wet surfaces, they can and do start growing, this becomes mould that grows generating more spores
- Mould and spores in the building can cause respiratory disorders and asthma in the young, unwell, older and frail people
- In worst cases toxic mould can cause death; forcing buildings to be abandoned and sealed up