Noticed a crack in your brickwork? Before you panic, it’s worth understanding what’s actually causing it.
Magda and I recently attended an interesting CPD session with Target Fixings and Target Structural, looking at structural movement, cracking and the different ways buildings can be repaired.
One of the biggest takeaways was that not every crack means subsidence. In fact, there are lots of reasons why buildings crack, and understanding the cause is essential before deciding how to repair them.
Buildings Are Always Moving
We tend to think of buildings as solid, immovable structures, but different building materials behave differently.
Clay bricks expand and contract with temperature changes. Concrete and calcium silicate bricks can shrink. Older buildings constructed with lime mortar are often more flexible than those built with modern cement mortar.
Sometimes cracks are simply the result of these materials moving at different rates.
We saw examples where cracking had been diagnosed as subsidence, when the actual problem was thermal movement in the brickwork.
What Can the Cracks Tell You?
The position and pattern of cracking can provide useful clues.
- Stepped cracks in brickwork can indicate foundation movement, but they can also be caused by thermal expansion.
- Horizontal cracks may suggest corrosion of wall ties, particularly in older cavity walls.
- Vertical cracks can occur where long sections of brickwork have insufficient movement joints.
- Cracks around windows may develop because these are weaker areas of masonry or because of movement in the surrounding materials.
Interestingly, we learnt that some older steel wall ties can expand considerably as they corrode, effectively pushing the brickwork apart.
But it’s important not to diagnose a structural problem from the crack pattern alone.
Trees, Drains and Foundations
Trees and leaking drains can also contribute to structural movement, particularly where properties are built on shrinkable clay soils.
Tree roots can remove moisture from the ground, causing clay to shrink, while leaking drains can affect the supporting ground beneath foundations.
However, removing a tree isn’t necessarily the answer. Changes in soil moisture after removal can create further movement.
The important thing is to establish what’s happening before deciding on a solution.
How Much Do Structural Repairs Cost?
One of the most useful parts of the session was discussing actual project costs.
Target Fixings shared some indicative figures:
| Structural repair | Indicative cost |
|---|---|
| Wall tie survey | Around £350 |
| Replacement wall ties to a typical 1930s semi-detached house | £6,000–£7,000 |
| Localised masonry reinforcement to an opening | Around £2,500 |
| Helical mini-piling | £240–£260 per linear metre of pile installed |
| More extensive piling and masonry reinforcement to a house | Potentially £28,000–£30,000 |
These were examples discussed during the CPD, not fixed quotations. Actual costs depend on access, the extent of the problem, structural design and the work required.
The wall tie replacement example included scaffolding, making good and dealing with the existing corroded ties.
What really interested me was how the right diagnosis could potentially save a homeowner thousands of pounds.
Do You Really Need Underpinning?
This was probably one of the most interesting parts of the session.
We looked at examples where substantial underpinning had initially been proposed, but further investigation showed that localised repairs or masonry reinforcement could be more appropriate.
Modern repair techniques include helical stainless steel reinforcement, crack stitching, replacement wall ties and specialist mini-piling systems that can be installed where access is restricted.
Sometimes these techniques can avoid the cost and disruption of more extensive structural work.
But there isn’t a one-size-fits-all solution. The repair needs to address the underlying cause, not simply cover up the crack.
Don’t Just Fill the Crack!
At Pride Road Architects, we regularly work with existing buildings, particularly when homeowners are planning extensions or internal alterations.
One of the most important things is understanding the building you’ve already got before making changes.
If you’ve noticed cracking, particularly if it’s widening, recurring or accompanied by distortion, it’s worth getting professional advice rather than simply filling it and hoping for the best.
A structural engineer or suitably qualified building surveyor can help identify whether movement is ongoing and what repairs, if any, are needed.
The message from our CPD was simple: diagnose the problem before spending money on the solution.
Thanks to Target Fixings and Target Structural for an informative session and some fascinating examples of structural repairs.
At Pride Road Architects, we help homeowners across Cheshire and South Manchester understand their existing properties and explore the possibilities for extending and refurbishing their homes.
