If You Read One Article About Cavity Wall Lintels Read this One

by scott douglas

Does your Property have Cavity Walls? If so, you will likely have Cavity Wall Lintels installed.

Cavity Walls have been a popular choice in UK Properties since the 1920s

Before we move on to the Cavity Wall Lintels, what exactly is a Cavity Wall?

A Cavity Wall is constructed of two walls, also known as inner and external leaves or inner and outer leaves the terminology we will use.

WADE BUILDING SUPPLIES | CAVITY WALL UNDER CONSTRUCTION SHOWING OUTER LEAF AND INNER LEAF AND INSULATION PLACED IN THE CAVITY

The outer wall is the external Leaf, and the inner wall is the internal leaf.

Inner and external Leaves of the Cavity Wall is separated by a Cavity that is typically around 100mm.

Wall ties link the inner and outer leaves to provide more stability and strength.

The Cavity now prevents the moisture from travelling from the external leaf to the inner leaf.

A Finished Cavity Wall provides a space for insulation.

The Cavity Walls Inner Leaf will carry the Structural Load and is typically built from concrete blocks.

An Outer Leaf tends to be constructed from Bricks and tends to be non-load bearing.

Therefore, any water which finds its way into the Cavity Wall will drain out through weep holes in the outer leaf, keeping the moisture away from the inner leaf.

External Cavity Walls

There are many Key Benefits to your Cavity Wall.

External Cavity Walls have a proven track record are simple to build and meet your Homes Fabric energy efficiency.

Key Benefits

  • Robust and Durable
  • Accessible Materials
  • Familiar to UK Builders and Constructers
  • Cost-Effective
  • Building Fabric Efficiency
  • Adaptable to Building Extensions / Alterations
  • Accessible to Address Foundation Level Issues
  • Offers Acoustic Performance
  • Good Thermal Mass


Steel Lintels


Before installation starts, you must have the correct Lintel for your Cavity Wall.

Steel Lintels manufacturers offer help with Lintel Selectors, and as a UK Lintel Distributor, Our In House Lintel Technical Engineers can assist with any lintel queries you may have.

Different types of Lintels include Steel Lintels, Timber Frame Lintels, Concrete Lintels.

When considering which New Lintel you need, start by accessing

  • Type of Wall Construction
  • Dimension of Structural Opening
  • Total Load on the Lintel

WADE BUILDING SUPPLIES | LINTEL SELECTION STRUCTURAL OPENING WALL CONSTRUCTION AND LINTEL LOAD

Different types of Wall Construction include

  • Timber Frame
  • External Solid Wall
  • Internal Partition | Load Bearing Wall
  • Cavity Wall

When measuring your Structural Opening, ensure you calculate the minimum recommended bearing length of 150mm

When calculating the Total Load of your Lintel, you must consider

  • Timber Floor Joists
  • Roof Trusses
  • Masonry

Always consult a Structural Engineer before applying Concrete Floor Loads.

Our Lintel experts can also help with Concrete Floor Questions.

Finally, before you begin the installation, Check your Steel Lintel or Concrete Lintel to ensure it is free from Damage.

Installation Tips | Cavity Lintel

Now you have selected the correct Lintel, start by ensuring the Brick and Blockwork Inner and Outer Leaves are level and complete in Bearing Areas.

You should not use Cut Blocks at bearing points.

Before placing your Cavity Lintel, add a think mortar bed to the inner and outer Brick and Block.

Place your Lintel, ensuring the Outer Leaves are supported with a minimum bearing of 150mm on each side, considering the required load.

Ensure your Lintel is installed correctly and is level across both length and width.

Place blockwork over the Inner Leaf Channel, ensuring an entire block is in position over the line of the Open Span.

A national house building council requirement is to simultaneously apply a flexible damp proof course over your Lintel and outer leaves.

Some Lintels, including Catnic Cavity Wall Lintel, will offer the added protection of a Duplex Corrosion Protection.

WADE BUILDING SUPPLIES | CATNIC CAVITY LINTEL WITH Duplex Corrosion Protection

This innovation from Catnic Lintels means the added protection of Duplex Corrosion makes the installation easier with less chance of incorrect installation of Damp proof course - dpc

To Help with extracting Moisture, place one or two weep vents on the Damp Proof.

Weep Holes should be 450mm maximum centres with at least two weep holes per opening.

Cavity Tray or Lintels should also have Stop ends.

You can purchase Catnic Weep Vents and Stop Ends together to save time.

Buy Catnic Weep Vents and Stop ends Packs.

All Block and Bricklaying mortar must be well cured before constructing loads, including applying floor loads.

Timber floor Joists and Roof Trusses should have full block depth between them and lintel flanges.

When installing Lintels for Windows, consider using Lintel Soffit Cladding for extra protection, particularly if you are located near a Coastal Region or an area with High Levels of Moisture.

Of course, Lintel Projects are rarely the same, but we have tried to give you a general overview of fitting Cavity Lintels, which is not as daunting as you may expect.

Some extra pointers include, You should not Cut Lintels (cavity) unlike some varieties of Concrete Lintel, which can be cut on Site.

If you are installing concrete floor units, we would strongly recommend speaking with your Engineer, or you are welcome to contact our Lintel Technical Team for advice.

Always check with your Supplier of Steel Lintels or Steel Lintels Manufacturer if you have any questions regarding fitting or an existing Lintel issue.

The Lintel information provided is related to Catnic Cavity Lintels and Stressline Cavity Lintels.

WADE BUILDING SUPPLIES | CATNIC LINTELS STRESSLINE LINTELS

Please ensure Lintel Installation instructions provided by your Steel Lintels Manufacturer or Supplier is followed.

What does the Future Homes Standard mean for Cavity Lintels?

Lintel Manufacturers have been fast to embrace the New Building Regulations in Part L of the Future Homes Standard.

Higher Standards of Building Fabric are required, and a big part of the change will be reducing Thermal Bridging Heat Loss on New Dwellings with changes to U Values set out in the Future Homes Standard.

Lintel Manufacturers are way ahead of the Curve and have developed Cavity Lintels offering reduced psi values between 0.02 and 0.05 W/mK, including the Catnic Thermally Broken Lintel ahead of the 2025 Changes.

For more information on Catnic Lintels | Birtley Lintels | Stressline Lintels | Naylor Lintels, Browse our Website or Contact our Sales and Technical Teams

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