Document O changes – and how it affects you

With the changes taking effect on 15th June 2022, many will already be in place on projects across the UK. However, on 15th June 2023 (less than six months from now), the Document O changes will be fully implemented and projects will be expected to have made significant progress towards the new regulations. Otherwise, they may be in line for fines.

What are the changes?

Building overheating has been a problem for a long time, but this is the first time the UK government has addressed the issue directly.

The new Approved Document O outlines the overheating mitigation requirements of the new building regulations.

Requirement O1 Overheating Mitigation of the Building Regulations states that dwellings, or other buildings containing rooms for residential purposes, should make reasonable provision to:

1. Limit unwanted solar gains in summer
2. Provide an adequate means to remove heat from the indoor environment

Mechanical cooling may only be used where insufficient heat is capable of being removed from the indoor environment without it.

Alongside meeting these obligations, the safety of occupants must remain a paramount factor.

Compliance with this requirement can be shown by using one of the following two methods:

1. The Simplified Method, as set out within Section 1 of the Approved Document O
2. The Dynamic Thermal Modelling Method, as set out within Section 2 of the Approved Document O

Dynamic Simulation Modelling (DSM), often referred to as thermal modelling, utilises computer software to assess the environmental performance of buildings. This can offer a selection of useful metrics for planning and implementation of Document O regulation.

Why the wait?

The changes were announced with a year’s notice to help aid compliance. They were announced last year to give construction firms and project managers enough time to implement the changes.

The 12-month transition period means that designers and developers were able to change planned projects, both already underway and due to commence soon, increasing compliance and ensuring a smooth transition to the new regulations.

What is the aim of the changes?

Alongside document O, there were many changes in the National Building Regulations that are aimed at reducing carbon output on new construction projects from 2022 onwards.

According to the government, 40% of the UK’s energy use comes from the heating and powering of buildings.

There is a huge investment from the government in trying to achieve net zero and one element of that is reimagining the building practices for domestic and non-domestic construction across the UK.

As a low-carbon consultant, we understand the importance of reducing carbon output within our projects and are proud to have helped increase energy efficiency on countless projects.

Get personalised advice on what Document O means for you

The document O changes may seem like a lot to consider, but we can help make sense of the regulation changes and ensure your portfolio, current and future, are compliant and energy efficient in line with all government guidance.