Lintel replacement over windows and doors

Every window and door in a masonry wall has something spanning the gap above it, carrying the brickwork overhead. In older houses that might be a timber bressummer hidden behind the brick face, a concrete lintel, a steel bar or a brick arch. When that support rots, cracks, rusts or sags, the brickwork above starts to drop and cracks climb from the corners of the opening. Windows may stick, and the frame itself can end up carrying load it was never designed for.

Replacing a lintel is a careful but routine repair. The wall above is propped or needled so nothing moves, the old lintel is cut out, and a new one is set on proper bearings at each end. Where the wall has a cavity, a tray goes in above so that water drains outward instead of soaking the new work. Inside and out, the opening is then made good so the repair is hard to spot.

What are the signs you need lintel replacement?

• A diagonal crack climbing away from a window head
• Brickwork above an opening visibly dipping in the middle
• Window or door frames that have started to bind or distort
• Rust stains or flaking steel showing above the frame
• Soft, crumbly timber visible behind the brick face over a bay
• Damp patches on the inside wall just above a window

What causes it?

Rotten timber lintels

Many Victorian and Edwardian houses have timber lintels behind the outer brick skin or across the inner face of solid walls. Once rain gets in through failed pointing or a leaking sill, the timber rots and slowly compresses. The brickwork above then drops, often most visibly over wide bay windows.

Corroded steel lintels

Steel lintels from the mid-twentieth century onward can rust where their protective coating has failed or where water collects on the flange. Rust expands, lifting and cracking the brickwork bedded on it. Severe corrosion eventually thins the steel until it bends under load.

Cracked concrete lintels

Concrete lintels crack when their reinforcement rusts and swells, or when they were undersized for the wall above. Spalling concrete with exposed bars on the underside, or a crack running through the middle of the lintel, are both signs it has stopped doing its job.

Short bearings and replaced windows

Some lintels were set with too little length resting on the wall at each end, so the masonry under the ends crushes. Older replacement windows were sometimes fitted after removing the original timber frame that was quietly carrying load, leaving the lintel above to sag.

How is it repaired?

How much will lintel replacement cost?

The price depends mainly on the width of the opening, whether it is a bay, how much wall sits above, whether inner and outer lintels both need replacing, and the access. Removing and refitting windows and internal making good add to it.

See regional prices on the prices page or work out a guide price for your home with the guide price tool.

What happens, step by step?

1. Inspect the opening

   We look at the crack pattern, the type of lintel and what sits above it. Pictures of both faces of the window, plus any visible lintel edge, help us judge it before visiting.

2. Specify the replacement

   We confirm the lintel type, length and bearing needed. For wide openings, bays or walls with unusual loads, an engineer may specify it, and where the repair needs an engineer’s design or sign-off we can arrange one.

3. Support the wall

   Props or needles are set so the brickwork above carries no load on the old lintel. Windows are protected or temporarily removed where the work demands it, and the room inside is sheeted against dust.

4. Remove and replace

   Brickwork is carefully taken out above the lintel, the old lintel removed and the new one bedded level on full bearings. A cavity tray goes in where relevant, then the brickwork above is relaid.

5. Remove supports and make good

   Once the mortar has gained strength, props and needles come out and their holes are made good. Pointing, reveals and plaster are finished, and the window is refitted or checked for smooth operation.

How long will lintel replacement take?

Replacing a single lintel usually takes one to two days on site, with wide bay openings taking longer.

Do you need building control or a party wall notice?

What if you have an insurance claim open?

Insurers normally treat a lintel lost to rot, rust or age as wear and tear, which policies tend to exclude. If cracking around an opening is part of wider movement you think could be subsidence, tell your insurer before permanent repairs start, so the cause is investigated rather than the symptom repaired. We can price to your loss adjuster’s or engineer’s schedule where the lintel forms part of a claim.

Lintel replacement: frequently asked questions