Manufacturer Welcomes New PAS Airtightness Guidance but Warns About Ventilation

A ROOFING component manufacturer has welcomed toughened airtightness standards for government-funded whole house retrofits but is warning against overlooking the role of ventilation.

The warning from Klober follows updates to PAS 2035/2030:2023, which focus on energy efficiency and airtightness. The PAS standard is followed by project managers and installers who are working on whole house retrofit projects.

PAS 2030 certification covers installation requirements in existing dwellings and is a means of access to grant-funding, such as the ECO+ Scheme. While PAS 2035 specifies the retrofitting requirements for compliance against funding regulation. Together they set out best practice for “whole house” retrofit projects.

Airtightness Guidance

Nick King, Portfolio Manager at Klober, welcomes the latest updates but restates the importance of ventilation: “It’s great to see these latest steps for addressing airtightness, particularly in line with energy efficiency regulations and decarbonisation targets. However, we cannot forget that properties that are ultra-airtight by design may face increased risk of condensation due to humidity levels, so appropriate ventilation is crucial.”

Ventilation

Under PAS 2030, retrofit installers must investigate and determine whether the installation of energy efficiency measures (EEM) would compromise the functionality of existing ventilation systems in relation to air movement within dwellings.

“If effective ventilation isn’t implemented, or is compromised through EEMs, occupants could experience mould and damp issues,” said Nick. “Installers have a crucial role to play in ensuring airtightness and ventilation are balanced. It’s positive to see this acknowledged within PAS 2030.”

“However, while awareness of solutions including trickle vents, dehumidifiers and extractor fans is commonplace, ventilation for the roof space must also be considered. Failure to ventilate roof voids could increase the risk of condensation, and associated risks, in the ceiling joists and in the uppermost rooms in the home.”

Health Risks

Mould and damp in a property can lead to health risks such respiratory problems, infections and allergies, and the worsening of existing conditions such as asthma.

Nick added: “Not only is prolonged condensation exposure a big health risk, but it can also cause structural issues, such as rot. Retrofitting solutions like dry ridge systems and roof tile vents are key ways to preserve home health, from an occupant-safety and structural perspective. Roof ventilation measures can enable ‘easy breathing’ in a space that is also super airtight.”

Retrofit installers can find out more about recommended ventilation requirements here.  

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