Lintel Load Calculations: Basics and Considerations

 

When designing a building, especially one with openings like doors and windows, one key structural component often goes unnoticed: the lintel. Lintels are horizontal structural members placed above openings to carry the load from the structure above. Correct lintel load calculations are critical to ensuring structural safety and compliance with building regulations.

In this blog post, we’ll walk you through the basics of lintel load calculations, the factors that influence them, and some best practices to keep in mind.

 

What Is a Lintel?

A lintel is a horizontal support element that spans across an opening in a wall, such as a window, door, or fireplace. It transfers the load from above the opening to the adjacent wall structure.

Lintels can be made from various materials, including:

• Concrete
• Steel
• Timber
• Stone

 

Why Lintel Load Calculations Matter

Failing to correctly size and install a lintel can result in structural cracking, sagging, or even failure. That’s why structural engineers must carry out accurate lintel load calculations to:

• Ensure the lintel can bear the load safely.
• Prevent deformation or collapse.
• Meet local building codes and regulations (such as those outlined in the UK Building Regulations – Part A).

 

Basic Principles of Lintel Load Calculations

To calculate the load on a lintel, you need to understand what loads are acting above it. These can include:

1. Dead Load

This is the permanent static weight of the structure above the lintel—typically including:

• The weight of masonry (brick or block)
• Flooring systems
• Roof structure (if applicable)

2. Live Load

Live loads are temporary or movable loads, such as:

• People
• Furniture
• Snow or wind loads (in roof applications)

3. Point Loads

These are concentrated loads, such as:

• Roof trusses
• Beams
• Joists

 

How to Calculate the Load

The most common method involves the triangular load distribution or 1:1 rule, where the effective area of masonry above the lintel is considered at a 45-degree angle (or 1 unit high for every 1 unit wide).

Formula (Simplified):

Total Load = Area of masonry above x unit weight of material

You must then add any point loads that fall within the triangular load area.

 

Key Considerations

When calculating lintel loads, consider the following:

1. Span Length

The longer the span, the more bending moment the lintel must resist. Always match the lintel size and material to the span.

2. Support Conditions

Ensure the lintel has adequate bearing at each end—typically a minimum of 150mm on masonry.

3. Material Strength

Use the manufacturer’s specifications or engineering tables for steel or concrete lintels to check their load-bearing capacity.

4. Building Use

Loads will differ depending on whether the building is residential, commercial, or industrial. For example, a domestic property has different live load requirements than a warehouse.

5. Compliance with Codes

In the UK, lintel design should comply with Eurocode 6 (EN 1996) or BS 5977, as well as Building Regulations Part A (Structure).

 

Tools and Resources

• Lintel manufacturer load span tables (e.g., Catnic, IG, Keystone)
• Structural design software (e.g., Tekla, Robot, Tedds)
• Building Regulations Approved Document A
• Consult a structural engineer for complex scenarios or non-standard openings

 

Final Thoughts

Lintel load calculation is a crucial step in any structural design involving wall openings. Whether you're a structural engineer, architect, or builder, understanding the basics of how to calculate and accommodate loads on lintels can save you time, cost, and potential structural failures.

When in doubt, always refer to an experienced structural engineer or relevant standards. A correctly designed lintel is not just a line above a window—it’s a key to the safety of the entire structure.

Need help with lintel design or structural calculations?
Feel free to contact us or comment below with your questions!