Window Formers

Subframes UK is the market leader of welded and mechanically joined window formers in the UK

At Subframes UK, we are the nation’s largest supplier and manufacturer of high quality, BBA certified window formers to suit all makes and types of PVCu windows and doors.

Situated in our Midlands-based factory, our experienced team manufactures premium window formers for commercial and domestic properties alike. Each product is subject to rigorous quality control before leaving our facility and delivered nationwide on a daily basis.

We provide a bespoke service designed to meet the specifications of particularly unique homes and commercial properties. You can choose from 2, 3, or 4-sided frames, with or without vented heads. Our range of window formers is available in a variety of shapes, such as circles, arches, ovals, mosque-inspired design, or a combination of T or P-shaped flags.

For those interested in windows casement options, our formers are compatible with various styles, ensuring a perfect fit for your project. When deciding on the best windows choose our products for unmatched quality and durability.

Our extensive collection includes standard, fire-rated and structural closers, spanning sizes from 50mm to 300mm.

Product lengths

All profiles comply with Building Regulations Part L and are available in lengths of 6 metres or can be custom-cut to specific dimensions. We offer a diverse range of products sourced from some of the UK’s top manufacturers in the industry, including Cavalok, Dacatie, Kingspan, Timloc and Titon Vents.

Quick Enquiry

FAQs

What are window formers?

Window formers, also known as cavity closers, are important components in building development. They create a barrier against potential gaps by fitting within the cavity walls at the reveals where windows and doors are installed.

At Subframes UK, our profiles are suitable for a range of build types, including brick and block, timber frame, Metsec steel frames and more. All our frames are fully welded and can close any cavity from 50mm to 300mm using a variety of profiles.

Do I need to use a window former?

Window formers are the most efficient way to insulate properties by sealing cavities around wall openings to address thermal loss. They contribute significantly to sustaining the energy performance of a building, protecting it from factors such as water ingress, damp, heat loss and condensation.

Additionally, during the construction process, cavity closers can be used in place of dummy timber frames by providing a solid, square template. This not only reduces waste but also provides greater convenience to builders by facilitating quicker and more precise bricklaying.

Are standard window formers fire-rated?

In general, standard window formers are not fire-rated. However, at Subframes UK, we recognise the importance of fire safety and offer specialised fire-rated profiles. For example, we proudly supply Cavalok FlameBlok – a cavity closer with a 1-hour fire rating.

Subframes UK caters to various construction needs, offering both standard and fire-rated cavity closers tailored to timber windows and doors, including types of composite door. For detailed information on our fire-rated options or to discuss your project requirements, please reach out to our team by calling 01773 590100, or send an email to [email protected].

How do I choose the right window former for my specific project?

When choosing the appropriate window formers for your project, there are a few factors to consider. If the former is being installed during the construction of the cavity wall, you can choose between pre-formed cavity closers or lengths.

For installations after the wall has been constructed, the profile can be cut to the desired cavity size. To do this, you will need to determine the cavity width, measuring across the cavity from the inner to outer leaf of masonry. Subframes UK offers a variety of cavity closers that are compatible with various project requirements, ranging from 50 to 300 millimetres.

If you need assistance with your project, feel free to contact our experienced team for personalised guidance and support.

How does Subframes UK ensure the quality of their products?

Subframes UK upholds the highest industry standards in both the administration and manufacture of our BBA-certified cavity closers. As a registered ISO 9001-2000 company and active members of the Chamber of Commerce, we consistently apply our set standards to all of our products manufactured in our state-of-the-art factory.

This includes adherence to specifications such as bracing quantity, bracing spacing, corner stays, customer information and identification.

Our deliveries are made with third parties that use unmarked transport, where proof of delivery is supplied to the manufacturer. Overall, we are committed to ongoing improvements in both service and quality throughout our company.

How can I order this product?

In order to process and complete your enquiry, please fill out our dedicated order form on our website. Our standard procedure involves providing a quotation within 24/48 hours, although take-offs from drawings might require additional time.

For inquiries related to quotations, product details, or technical assistance, feel free to contact us at 01773 590100 or send an email to [email protected]. The expert team at Subframes UK would be delighted to speak with you about your next project.

Do window formers work with aluminium windows?

Yes, our window formers are designed to be compatible with all types of windows, including aluminium windows. Whether you are installing PVCu windows, aluminium windows, windows timber our window formers ensure a precise fit and superior performance.

For more information, you can choose from our range of products on our Cavity Closers page.