Building Standards

Section 3.14 gives guidance on domestic ventilation. The ventilation methodology has changed and almost aligned with the English ADF in 2023.

Section 2.2 gives guidance on fire separating walls and ceilings.

Section 6 gives guidance on mechanical ventilation and air conditioning.

Since 2023 the ‘Supporting Guidance Domestic Ventilation’ has been incorporated into the Technical Handbook as Appendix 3.1.

According to the ADF/ Scottish Technical Handbook (STH) the minimum ventilation rates for dwellings are calcularted for the…

• Nominal ventilation rate, which is the normal operation mode. This is the higher value of one of the following:
  • the floor area of the dwelling
  • the number of bedrooms (ADF) or seperate habitable rooms (apartments) (STH)
• Boost ventilation rate, which is an increased ventilation rate to expel humidity more quickly.
  • The boost rate is based on the number of wet rooms and their associated min. high ventilaiton rates. If the boost rate comes out lower than the nominal rate, it is adjusted to the nominal level (or above).

The Passive House Guidance is giving more specific details to well performing systems, curated from decades of research and practitioner’s knowledge of European and UK experts. These specifcally ensure that there is e.g.:

• high real heat recovery rates (very different test methodology from UK testing),
• very little heat loss through ductwork,
• very low loise levels,
• high durable and cleanable ductwork

1. The move away from flexible ductwork, which is already bad practice due to its high resistance and because it can be easily damaged and can never be cleaned.
2. More considered ventilation planning: Introducing pressure‑drop calculations for new MEV and MVHR systems, as well as dMEV with ducting more than 2m.
3. A proposed move to installer accreditation: New ventilation systems must be commissioned by a member of a competent person’s scheme or by the Building Control Body.
4. More comprehensive tests at commissioning: Powered flow hoods must be used. Rotating vane anemometers will no longer be permitted.

The Healthy Homes Standard is a concise set of design requirements and good-practice guidance. It is intended to be used by Homes England, their development partners, and design consultants involved in the funding, commissioning, development, planning, and design of new homes, to support the delivery of healthier living environments. It can also be used by other housing providers, developers, and design teams as guidance to inform good practice in the design of new homes.

The death of a two year old boy Awaab Ishak – which was attributed to the mould-infestation of his home – has highlighted a common problem: landlords were slow to react to complaints of critical housing defects or didn’t react at all.

From the 27th October 2025 all landlords must:

• Investigate hazards within 10 working days
• Share findings with the tenants within 3 days
• Complete urgent safety works within 5 days
• Begin further works within 5 days / or 12 weeks if more complex