We are in strange times. Surely a government announcement with the promise of lowering heating bills and 100,000 (much needed) more jobs to boost the economy could never be seen as a bad thing?! Add to this, it has also been packaged up as a “green investment” helping the UK meet its 2050 target of achieving net-zero carbon emissions. So a double whammy – saving the economy and the planet at the same time! Sounds brilliant…but why am I feeling a little concerned about a scheme that seemingly delivers so much?

This industry specialises in dealing with defects as a result of dampness in the built environment and I’ve had numerous conversations with our members, who have reported growing numbers of incidences of dampness as a consequence of retrofit. So naturally, I have been watching the events following Rishi Sunak’s £2bn home insulation scheme announcement very closely.

Lets think about avoiding previous problems

“Unintended consequences” has felt like one of the buzz terms in the last few years with the more airtight we make our properties (without taking a proper and holistic approach to improving the energy efficiency of our building) the more likely we are to end up with “unintended side effects” to the intended good planned for the property. Principally this will be dampness and mould.

By the reducing the amount of air escaping our homes and buildings by draft proofing and insulating, we are also preventing moisture escaping too. Modern lifestyles mean we now produce a huge amount of moisture within our homes through cooking, cleaning, washing and of course breathing; all of which produces moisture. Historically moisture would escape through drafty windows and chimneys etc, but as we make our properties airtight this is no longer the case.

Why is it important that moisture is controlled?

Excessive humidity can provide the perfect conditions for mould growth and condensation. If the conditions are right for mould growth, then they are probably right for other indoor air quality issues too. A supply of fresh air is not just important for controlling moisture, but also for:

• Supplying air for breathing
• Dilution and removal of pollutants
• Air for fuel burning appliances
• Temperature control

This means that if we are to avoid “unintended consequences” we must ensure that in addition to the retrofit measure – the insulation, windows etc that are available through grants – we must also be ensuring that the property is adequately ventilated. Typically, this is provided by mechanical ventilation. There are various mechanical ventilation systems, but most commonly, they are extractor fans in the kitchen and bathrooms.

Before you insulate, ask yourself ‘how is my home ventilated?’

If you are thinking of insulating your home, you should also be thinking about how your house is ventilated and is it enough to avoid the “unintended consequences”.

We understand that in the latest roll out of the green homes grant scheme that ventilation will be eligible for the scheme. This is a very welcome development. As homeowners will be enticed by the prospect of lower heating bills, little if any consideration will be given to the wider-reaching consequences this might have on the internal environment. Ventilation should not be an afterthought and we hope that proper consideration is given to install appropriate ventilation.

Assessment of ventilation is a specialised subject

Some of the new guidance being provided around retrofit, which unfortunately will not be enforced by the time this scheme is rolled out, does give some consideration to ventilation. Whilst this is commendable, one concern is that it places the assessment of building services such as ventilation on limited criteria, and principally assumes the presence of a ventilation system is sufficient.

In my experience, assessment of ventilation is a specialist subject and making the assumption that it is adequate based solely on its presence without appropriate testing and assessment, is likely to result in issues of dampness and mould which may potentially be harmful to occupants.

Make sure it complies with Building Regs

Unfortunately there are also a number of pitfalls when looking to have ventilation installed. Whilst I will not go into any great depth on these here, if you are looking to get ventilation measures installed ensure it always complies with the relevant building regulations, principally Approved Document F – Means of Ventilation. This was the very reason the PCA residential ventilation group was set up.

We would recommend that ventilation providers should be speaking to their local green deal contractors to help them fulfil the ventilation requirements under the new green deal scheme.

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