Streamlining Building Projects with Cavity Closers

Understand the importance of cavity formers and their benefits in new build development projects.

Cavity formers, also known as cavity closers, window formers, or frame formers, are essential components in the construction of new buildings. They can be used across various applications, including masonry, timber frame, and steel frame systems.

While we’ve previously discussed the role of cavity formers/closers in construction projects, this article delves deeper into their specific benefits, particularly in streamlining building projects for developers and builders.

Cavity closers have two main benefits:

  1. They safeguard the development project against water penetration, heat loss, dampness, and condensation.

  2. They serve as a guide/template for window and door installation by pre-defining the dimensions, allowing for their installation at a later stage.

Why Are Cavity Closers So Important In New Build Developments?

In addition to facilitating the progress of building projects, they provide a multitude of other advantages.

Exceptional Thermal Performance:

Cavity formers, or closers, provide exceptional thermal performance for properties. They are the most efficient and secure way to seal cavities around wall openings.

Comply With Building Regulations:

Every new build development project must comply with Part L of the Building Regulations, and cavity formers are just one easy way to do that.

The construction of new properties entails numerous considerations. As construction industry experts, it’s vital to prioritise building homes that minimise the likelihood of future problems, such as mould growth and condensation.

Tackling Tight Deadlines:

At Dale Joinery, we collaborate closely with builders, developers, and architects to ensure seamless project execution within specified timelines. Our cavity formers enable builders to accommodate tight schedules and integrate smoothly with other contractors' timelines. Opting for cavity formers enhances efficiency and reduces on-site errors.

In addition to the above, insulated cavity closers also provide the following key benefits:

Easy installation.

Reduces the risk of condensation, mould and moisture migration across the cavity.

Complies with Part L Building Regulations.

GWP levels less than 5, OPD Zerio and Green Guide A+.

Reduces cold bridging.

What Are Other Benefits of Cavity Formers?

Cavity formers offer outstanding thermal performance for properties. They serve as the most effective and secure method for sealing cavities around wall openings.

Reduces Heat Loss

Part L of the Building Regulations, which addresses energy efficiency standards, mandates that cavity closers possess a minimum thermal resistance path of 0.45m2k/W.

Cavity closers prevent thermal loss from occurring within uninsulated walls, helping to keep the building warm and complying with Part L Building Regulations.

Prevents Water Ingress

Formers work hard to prevent water from occurring around the edges of a window or door - essentially acting as a damp-proof solution to reduce condensation and mould. 

Preventing water ingress is paramount in ensuring the building’s compliance with Part C Building Regulations concerning resistance to contaminants and moisture.


Formers can be manufactured as 2, 3, or 4-sided frames - all made bespoke to your project and utilising different cavity thickness options to suit your project. 

Improves Window Installation

The use of cavity formers allows window and door installers to revisit the project at a later date and fit the windows much quicker, streamlining the window installation process entirely.

Improves Fire Safety

There are standard cavity formers and fire-rated cavity formers. Fire-resistant window formers can prevent a fire from spreading for 30 minutes to an hour. 

Opting for fire-rated cavity formers not only enhances fire safety measures but also ensures compliance with Part B Building Regulations.

Additional Resources from Dale Joinery.

How To Install Cavity Formers.

Cavity Former FAQs.

Contact Us

Our timber cavity formers are BBA-certified, bespoke and competitively priced. If you’re in need of formers for your project, please get in touch with our expert team. Use our contact form online to share the following information:

Drawings that include the overall width and height.

Fire-rated requirement.

Check reveal requirement.

Cavity width.

We will provide you with a quote based on your information, but you can also give us a call on 0808 304 4884 to learn more about Dale Joinery’s cavity formers and services.