Updated Building Regulations and What They Mean for Windows and Doors

The UK is paving its way to become net zero. What does this mean exactly? The government are hoping by 2050 that the UK will no longer be adding to the total amount of greenhouse gases in the atmosphere. Therefore, many changes have been made to building regulations over the past few years.

Understanding building regulations can sometimes be quite tricky, so we have tried to break them down into manageable sections relevant to windows and doors.

WHY DO WE NEED BUILDING REGULATIONS?

Building Regulations set minimum standards for construction and safety protocols. They are necessary to ensure the safety, health, and welfare of the public and building occupants. Cover areas like safety, accessibility, energy efficiency, environmental sustainability, and structural integrity.

APPROVED DOCUMENT L – CONSERVATION OF FUEL AND POWER

What does approved document L mean for windows and doors? Well, it is pushing for all windows, rooflights and doors in both dwellings and commercial buildings to become more thermal efficient, reducing the risk of cold draughts and maintain the heat within the building.

Within approved document L, it has been split into two sections, part one covering dwellings and part two covering commercial. Under the subheadings limiting values and notional values, both have different maximum values to comply by.

APPROVED DOCUMENT L – LIMITING VALUES

In limiting values, limits have been set for U-values, airtightness of buildings and the efficiency of heating and ventilation systems for developers, builders, and designers to ensure new builds, extensions or replacements are on par. This means that your windows and doors in either a new or existing dwelling or commercial property must be airtight and thermally efficient to comply with these updated regulations. So, remember, the lower the U-value the better!

APPROVED DOCUMENT F – VENTILATION

Approved document F sets the standards for ventilation and air quality for all buildings and covers the requirements to prevent condensation and mold growth. Trickle vents tend to pop up quite regularly and are a common addition to replacement windows and doors to allow for that trickling, constant air flow

New windows being fitted into existing window places need to have the exact same background ventilators. They must not be smaller and can be controlled either automatically or by the occupant

Some existing windows have no background ventilators, meaning replacement of these windows may result in an increase in airtightness within the dwelling. For windows to get away without having a background ventilation, then the ventilation specification in the dwelling must be no worse than it was previously. This can be demonstrated in any of the following ways.

• Habitable rooms – minimum 8000mm2 equivalent area
• Kitchen – minimum 8000mm2 equivalent area
• Bathroom (with or without toilet) – minimum 4000mm2 equivalent area

APPROVED DOCUMENT O – OVERHEATING

Document O covers the overheating mitigation requirements for new residential buildings, aiming to protect the health and welfare of the building occupants to ensure indoor temperatures do not rise. This means when choosing new windows and doors you must consider the glazing options, material of the frame for airtightness and in some cases the size of the window!

Building or parts of buildings should not exceed any of these maximum glazing areas.

There will be two methods to comply by:

• The Dynamic thermal modelling method CIBSE’S TM59 which can ensure dwellings comply with the document by modelling the building to predict the risk of overheating.
• The Simplified Method which considers the size and orientation of glazing and compares the glazing area to the floor. Window opening areas are also considered to deliver suitable purge ventilation.

The overall point of approved document O is to limit unwanted solar gains and provide adequate means to remove heat. So specialised glazing or a reflective film will come in handy to ensure you meet the correct specifications.

WHAT DO BUILDING REGULATIONS MEAN TO YOU?

Building regulations are important for your house or commercial property to be signed off as a habitable area. If it were to fail due to a lack of following the latest regulations, the building inspector can ask you to take down work and refuse to sign it off!

One thing we recommend is that if work is underway or soon to be, then you make yourself aware of what is needed to be achieved to reach regulations just in case something is missed and for a little personal understanding on what to expect!

Building regulations are not the most exciting read, however they are necessary and must be noted carefully surrounding anything under construction.