{"id":83740,"date":"2020-10-12T07:00:57","date_gmt":"2020-10-12T06:00:57","guid":{"rendered":"https:\/\/www.pbctoday.co.uk\/news\/?p=83740"},"modified":"2020-10-09T14:08:13","modified_gmt":"2020-10-09T13:08:13","slug":"green-homes-grant-scheme","status":"publish","type":"post","link":"https:\/\/www.pbctoday.co.uk\/news\/energy-news\/green-homes-grant-scheme\/83740\/","title":{"rendered":"Green Homes Grant Scheme: Beware unintended consequences"},"content":{"rendered":"

The new Green Homes Grant Scheme has worthy aims but, warns James Berry of the Property Care Association<\/a>, when it comes to insulation and ventilation, rushing into retrofit can bring serious unintended consequences<\/h2>\n

The Green Homes Grant Scheme was introduced at the end of September with the aim to stimulate the construction sector during the Coronavirus crisis, to help homeowners save valuable cash on their energy bills and take steps to reduce the country\u2019s carbon emissions<\/a>, all while (hopefully) improving the housing stock. Undoubtedly these are admirable and worthy causes.<\/p>\n

The sheer scale of the project, however, and the incredibly fast turnaround (announced late July, rolled out in September 2020, and finishing before Easter 2021) gives cause for concern. It is precisely another reason to look at and remind all building professionals of the consequences of poorly checked and installed insulation measures, and how we can avoid them.<\/p>\n

Moisture imbalance can lead to expensive complications<\/h3>\n

Cavity, internal and external wall insulation<\/a> changes a building and how it deals with water. An understanding of this is important not only to the designer of the retrofit insulation scheme but also to the building surveyor who will subsequently inspect insulated buildings, and to the people who own and use buildings.<\/p>\n

Dealing with moisture<\/a> generated within the building is relatively simple. Improving the ventilation system is acknowledged by almost everyone as a fundamental element of any retrofit insulation scheme. What must also be understood is that these augmented air extraction systems must be maintained for the lifetime of the building. Failure to repair, service and renew ventilation systems over time will result in expensive and unhealthy moisture imbalance.<\/p>\n

Understanding the principle of \u201cfabric first\u201d is key<\/h3>\n

The principle of \u201cfabric first<\/a>\u201d when considering retrofit insulation is taken from the highly regarded PAS2035. The principle being that insulation must never be applied within or over defects in the underlying building fabric. This mantra is hugely important and we would urge homeowners to insist on detailed pre-installation checks on the property before any insulation is applied.<\/p>\n

Moisture-related issues, blocked cavities, defective guttering and high ground levels should never be overlooked. In our experience, the risks of calamitous, costly and highly damaging issues with damp and timber decay are hugely increased when underlying defects are ignored or covered up.<\/p>\n

It must be remembered that retrofit insulation introduces new layers of material that can mask dampness, conduct or hold water, or even prevent the transition of moisture by drying. This is a fact and though it should not put people off insulating their homes, we must understand the increased importance of maintenance and keeping water out of the structure.<\/p>\n

Take cavity wall insulation, for example. Cavities filled with air are good at stopping internal walls getting wet even if the outside leaf or masonry is in poor condition. Fill it with insulation and even the best product installed by the most diligent installer can become wet and allow moisture transfer. This sort of direct correlation between what once may have been considered minor defects and the greater significance of water ingress to the retrofitted buildings can be seen in all forms of retrofit.<\/p>\n

Cavity wall and retrofit insulation fails<\/h3>\n

Cavity wall insulation has been a subject that successive governments over the past 30 years have attempted to promote. Previous government drives such as Eco and Warmfront have made it readily apparent that in many homes, instead of creating energy-saving conditions, the process locked dampness and humidity into many homes. This led to potentially expensive damp and rot repairs and, in some cases, structural problems.<\/p>\n

Quite simply, cavity walls exist for good reason and that is to provide a barrier against rainwater penetration. The problem is that a great many of these cavity voids are either simply unsuitable for cavity wall insulation, or unqualified specialists have overpacked the cavity with insulation, resulting in rainwater travelling through the insulation and reaching the internal wall. Thus, creating problems with penetrating damp, mould, condensation and rot.<\/p>\n

Why does this happen? Retrofit insulation<\/a> installers may have the best of intentions but these government-backed subsidies have always attracted a number of suppliers who are not sufficiently skilled. On top of that, as competent as a retrofit insulation specialist might be, they do not necessarily have the skills and knowledge to identify the potential ripple effects from the work they are doing.<\/p>\n

Let\u2019s think about avoiding previous problems<\/h3>\n

\u201cUnintended consequences\u201d has felt like one of the recent buzz terms 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 \u201cunintended side effects\u201d to the intended good planned for the property. Principally, this will be dampness and mould.<\/p>\n

By reducing the amount of air escaping our homes and buildings by draughtproofing 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 produce moisture. Historically, moisture would escape through draughty windows and chimneys but as we make our properties airtight, this is no longer the case.<\/p>\n

Why is it important that moisture is controlled?<\/h3>\n

Excessive humidity<\/a> 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:<\/p>\n