50mm Cavity Wall Lintels

50mm cavity lintels were introduced by Catnic when 50mm was the most common cavity size in house walls. It is significantly lower than more modern, much better insulated dwellings. Nowadays, Catnic lintels for a 50mm cavity are used in refurbishments and replacement situations in existing buildings. They deliver the structural performance and durability needed for long-term service in an established wall build-up, making them a great swap for failed or corroded lintels.

 

Manufactured from sustainably sourced steel that is 100% recyclable, Catnic cavity wall lintels offer a single-piece structural solution. Our lintels are backed by more than 55 years of UK manufacturing experience, combining dependable performance with Duplex corrosion protection and CFC/HCFC-free insulation for improved thermal efficiency.

 

Browse our full range of cavity wall lintels or buy direct today. 

CG50 lintel render

If you have a structural opening or need to support a masonry load, Catnic lintels can help.

Today’s building standards require far larger cavities to ensure homes have appropriately insulated walls.  50mm cavity wall lintels are therefore predominantly used for mid-century builds constructed before modern legislation came into force - with compulsory insulated cavity walls and the thickness of insulation gradually increasing every few years.

Read on to learn more about 50mm cavity wall lintels from Catnic and discover answers to frequently asked questions.

Support & FAQs

Catnic lintels are available in the following load capacities:

•    Standard — Safe working load up to 26kN
•    Heavy — Safe working load up to 48kN
•    Extra heavy — Safe working load up to 60kN
•    Extreme load — Safe working load up to 88kN

50mm cavity lintels come in standard, heavy, extra heavy and extreme load.

For guidance on cavity wall lintel selection, see our technical guide: Steel lintel solutions for masonry cavity walls. 

Specifications vary across the Catnic range, including load capacity, insulation thickness, and compatibility with partial-fill or full-fill insulation.  

Catnic 50mm cavity lintels are:
•    Available in various materials and finishes - including hot-dipped galvanised steel to BS EN 10346:2015 with zinc coating and a black polyester powder coating, and stainless steel to BS EN 10088-2:2014.
•    Available in multiple lengths – up to 4,800mm. 
•    Fully-filled - with CFC and HCFC-free insulation shaped to optimise thermal performance along the entire length, preventing cold spots. 
•    Certified - CE marked to harmonised European Standard BS EN 845-2:2013, BBA certified, and assessed as able to contribute to satisfying NHBC Standards Chapter 6.1 External masonry walls. Made in the UK and certified to BES 6001 Responsible Sourcing. 

Browse our lintels online or request a lintel schedule - a concise document detailing dimensions, load tables, thermal performance, and pricing. 

Duplex corrosion protection gives Catnic lintels lasting durability in service. Therefore, once a lintel is installed, maintenance is not required. However, appropriate pre-installation checks must be carried out.

Check the lintel for damage prior to fitting, and confirm the cavity is free of debris. Prepare the opening by inspecting for signs of damp, repointing mortar as required and verifying that insulation sits in the correct position.

Make sure to:
•    Confirm insulation has not bridged the cavity.
•    Verify the residual cavity is clear of obstruction.
•    Check DPC trays and stop ends have been installed correctly.

Both 50mm and 100mm cavity wall lintels look very similar, the latter having the cavity section noticeably wider. Both ranges have the same structural performance, same durability and are equally easy to install.

If you are unsure of what size cavity wall lintel you need, please consult our lintel selector tool. 

To ensure you have the right lintel, get in touch with our technical team on 029 2033 7900 or use our lintel selector to quickly identify the correct product for your project using defined search parameters. 

Catnic manufactures cavity wall lintels across cavity widths spanning 50mm to 225mm, with safe working loads ranging from standard through heavy duty to extra heavy duty.

Popular searches include:

100m cavity lintels  

150mm cavity lintels  

•    As the UK's leading manufacturer, we were the first to achieve BES 6001 certification.
•    Our steel is responsibly sourced and fully recyclable.
•    We've built a reputation for dependable products since 1969.
•    A knowledgeable customer service team is on hand to help.
•    Our scheduling service comes at no cost.
•    A wide selection of our lintels can be bought right away. Buy direct from Catnic here. 

  • Book a CPD

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Download Lintel Whitepaper

Unlock practical, up‑to‑date guidance on modern lintel specification. Three expert whitepapers cover thermal breaks, Part L & Future Homes Standard compliance, and best‑practice lintel design for today’s residential builds, giving you the clarity you need to specify with confidence

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What our customers think

  • “We have found the thermally broken lintels well-made, easy to work with and durable. Using thermally broken lintels on site has helped us to comply with the Building Regulation Part L requirements in a simple, straightforward manner”

    George Sowerby
    T.G Sowerby Developments Ltd

  • “I recently placed two orders with Catnic and I can honestly say from speaking to the rep Toby, all the way to transport their service and communication regarding the orders was superb!.”

    Dave Daniels
    Travis Perkins PLC

  • "Catnic has always been very quick and prompt in getting back to us when we ask for quotes and any problems we may come across. Very useful and easy to deal with! Excellent!"

    George Atkins
    Turnbull

  • “Catnic is a leader in its field, and the high quality of its TBL is testament to that. The team has been on hand at every stage of this project so far, offering technical support during the planning stages and now into the early stages of installation"

    Matt Taylor
    RBLI

  • "We have been using Catnic Lintels for over 10 years, they are by far the best. A superbly well organised company who offer exemplary service, their lintels are extremely capable and well suited to our high quality homes."

    Chris Dodge
    County and Coast Homes

  • “Catnic worked with our drawings and outlined exactly what we needed - including the structural loading measurements. Catnic is the only manufacturer that provides such a comprehensive scheduling service for free. It really is invaluable."

    Mike Parkinson
    Keyworker Homes

  • "Catnic is able to provide quality products according to the demands of the project at a competitive price"

    Steve Blythe
    Skanska

Video Guides

When selecting a lintel, there are three factors that should be considered to ensure the correct specification: the type of wall construction, the dimensions of the structural opening and the total load on the lintel. In this video, we run you through the lintel selection process.

Catnic thermally broken lintel installation

Once you have chosen the correct lintel for your project, it is crucial that the lintel be installed properly – if it is not, it could lead to serious issues for the building. In this video, we explain the installation considerations for cavity wall lintels.

Builder installed Catnic CG90/100 lintel

Catnic’s Thermally Broken Lintel is the only lintel on the market to provide a complete thermal break between the inner and outer leafs. In this video, we outline the key benefits of Thermally Broken Lintels and explain the installation process.

Catnic TS90/100 lifted into position by builders

Steel lintels, and specifically Catnic's thermally broken lintels, have a significant role to play in reducing thermal bridging and achieving carbon gains. They represent one of the simplest and most economical ways for building fabric to be designed and constructed to help achieve the carbon gains necessary to meet current and future building regulations.

Catnic balcony installation at kingsdown gate

Lintel Resources

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