We’ve taken a deep dive into the latest building regulations to help systems houses and fabricators stay up to date with Part L approved documents to guarantee the bi-fold systems they develop and work with are fully compliant.

Before we begin, let’s first explore and understand exactly what the regulations are and how this will affect the manufacture of any new bi-folding doors moving forward.

Overview of the Part L building regulations in England and Wales

The Part L building regulations set the standard for the energy performance and carbon emissions produced by both new buildings and existing properties across the UK. The approved documents act as temporary regulations ahead of the Future Homes Standard which officially launches in 2025.

In simple terms, under these new standards replacement windows and doors will need to conform to the WER, DER or U-values stipulated in Document L. They impact everyone involved in the design, construction or renovation of buildings in England which means it’ll also apply to companies responsible for developing, engineering or designing the materials or systems used in these properties.

Part L was originally introduced in June 2022 but everyone operating within the construction industry was given a 12-month period to make the required changes to ensure all products would be fully compliant. On 15 June 2023, the grace period came to an end, so companies must now comply with the regulation changes or risk being hit with a fine.

What are the compliance requirements for bi-fold doors under Part L?

Sliders UK bi-fold door

With these regulations now in force across England and Wales, what do the new standards mean and what are the compliance requirements for bi-fold doors in particular?

Well, from a glazing perspective, Approved Document L (or Part L) has introduced a reduction in the U-values required for doors, decreasing the value from 1.8 W/m2K to 1.4 W/m2K on all extension and renovation projects. The same standard has also been set for new dwellings, where the U-values have been once again reduced to 1.4 W/m2K for doors with >60% of internal face glazed.

For more information about the regulations and how the changes may affect you, check out Approved Document L here.

Methodology for calculating U-values under Part L

In terms of limiting heat gains and loss from a property under the new building regulations, as the measurement used to show how a product conducts or transfers heat in a property, U-values play a fundamental role.

To correctly assess whether the bi-fold door meets the limiting U-value (mentioned above) either one of the following methods should be completed.

1: U-value of the door calculated using the actual size and configuration of the door.

2: U-value of the door calculated using one of the following standard sizes:

  • 1.23m (±25%) wide × 2.18m (±25%) high, for doors ≤ 3.6m²
  • 2.00m (±25%) wide × 2.18m (±25%) high, for doors > 3.6m²

Part L compliant slimline bi-folding system

The most secure bi-fold door

Although we primarily focus on the manufacture and design of innovative bi-fold hardware including handles, locks, door catches and hinges, our journey in the bi-fold market actually started by developing our own bi-fold door systems.

Many years ago we created the renowned Dewall aluminium bi-fold door system and more recently we supported Cortizo with the development of an innovative slimline bi-folding system which perfectly meets the new approved document energy efficiency standards.

Ideal for modern homes, commercial buildings and other projects looking for a minimalist and contemporary design, this system has been specially designed to provide high levels of insulation, helping to minimise heat loss and reduce energy bills – something that’s incredibly important under the new building regulations.

Made from advanced insulation materials and a thermally-broken frame means the system delivers exceptional thermal performance by successfully preventing heat from being transferred from the inside to the outside. It also achieves the required U-values set out in the new building regulations.

The system is also available in a range of colours, finishes and configurations to suit any design or specification. Plus, we supply the system so that it can be branded as your own.

For more information speak to our team today.

Expert advice and resources for navigating Part L regulations with bi-fold doors

To be able to smoothly navigate and adapt to the new Part L building regulations speak to an expert in the field to ensure proper installation and compliance with the changes that have come into play.

We have 15 years of experience in the bi-fold market and always stay up to date with the latest industry trends and changes. Speak to a member of the team today to find out how they can support you with your next bi-fold door project.

Alternatively, if you’d like to find out more information about the slimline bi-folding system we have developed in partnership with Cortizo, get in touch. We’d be more than happy to run through the requirements for your next bi-fold door installation.