Cracked Brickwork in Dunstable: How to Read the Crack
Cracked Brickwork Diagnosis — Dunstable, Bedfordshire · LU5, LU6
How to tell thermal movement, lintel failure and genuine structural movement apart before anyone quotes you for underpinning.
Most cracks we're called to in Dunstable (LU5, LU6) are not subsidence. They're thermal movement, a corroded lintel or an old repair opening back up — all fixable without a structural scheme. This guide explains how we work out which one you've got before quoting anything.
- County
- Bedfordshire
- Postcode district
- LU5, LU6
- From our Bidwell yard
- ~1 miles
- Nearby areas
- Bidwell, Beecroft, Northfields
Reading the crack on a Dunstable property
We start with width, path and whether it is tapering. Hairline vertical cracking at a corner or under a window is usually thermal or shrinkage movement. Stepped diagonal cracking that widens toward the top, particularly near a tree line or a made-ground boundary, needs a closer look. Horizontal cracking a few courses above an opening usually points at a corroded steel or a failing lintel rather than the ground. Most of the town sits on chalk and chalky boulder clay beneath shallow topsoil, which generally gives sound bearing for shallow foundations but rewards a proper trial hole before digging.
Lintels, wall ties and old repairs
Two very common causes on Bedfordshire housing are corroded lintels and failed wall ties. Both push brickwork apart and both look worse than they are structurally. A cracked bed joint running horizontally at regular intervals across an elevation is classic wall-tie failure and is repairable with remedial ties rather than rebuilding. Old cement repairs over lime-mortared brickwork also crack again as the wall moves — the repair is harder than the brick, so the brick loses.
When it genuinely is movement
Where a crack is over 5mm, still opening season to season, and matched by doors binding or a sloping floor, that is worth a structural engineer's opinion and, in most cases, a period of crack monitoring before anyone commits to underpinning. We do not quote structural schemes off a photo, and in Dunstable we would rather send you to an engineer than sell you work you may not need.
Local checklist for Dunstable
- Photograph the crack with a ruler or coin in shot, dated — repeat monthly
- Check inside as well as outside: does the crack pass through to the internal face
- Look at what is directly above and below — lintel, cill, downpipe, gully
- Note any tree within roughly its own height of the wall
- Check gutters and downpipes on that elevation for long-term saturation
- Keep the Dunstable property's build era in mind — pre-1919 walls move differently to cavity walls
Common mistakes we see in Dunstable
- Filling the crack with cement mortar before knowing why it moved — it simply reappears
- Accepting an underpinning quote without monitoring or an engineer's report
- Assuming every stepped crack in Dunstable means subsidence
- Repointing a whole elevation in hard cement when the wall was built in lime
- Ignoring a blocked gully feeding water into the foundation on that elevation
What crack repair usually involves in Dunstable
A lintel replacement or localised rebuild on a Dunstable property is typically a few days on site with propping. Remedial wall ties across one elevation are usually one to two days. Repointing a cracked area properly, in the right mortar, is priced by area. Where an engineer is needed we will say so and hold off quoting until their report lands — you should not be paying us to guess.
FAQs — cracked brickwork diagnosis in Dunstable
Will you repoint with lime on older Dunstable houses?
Yes. On pre-1919 Bedfordshire brickwork, lime mortar is the correct material. Cement pointing on those walls traps moisture and causes the face of the brick to blow, which is a far bigger repair later.
Do you cover the whole of Dunstable?
Yes — from Lewsey Farm and West Dunstable through to the Priory, California, Beecroft and out to Sewell. Being based in Bidwell we're rarely more than ten minutes away.
Do you charge for a crack survey in Dunstable?
Our initial visit and written assessment for Dunstable homeowners is free. If an engineer or formal monitoring is needed, that is their cost and we will tell you upfront rather than absorbing it into a repair price.
Do you need planning permission for an extension in Dunstable?
Many single-storey rear extensions in Dunstable fall under Permitted Development if you're not in the Conservation Area, but Central Bedfordshire planners will still want a Lawful Development Certificate or full application for anything larger or on a corner plot. We can talk you through it before you commit to drawings.
Ready to price the work?
This guide covers the planning side. For an on-site quote in Dunstable, see our bricklaying in Dunstable or read our other guide for Dunstable.
The short version
Photograph it, date it, look at what sits above and below it, and get an honest diagnosis before anyone prices a repair. Most cracked brickwork in Dunstable is repairable work, not a structural scheme.
Worried about a crack in Dunstable? Send us dated photos and we will tell you honestly whether it needs a builder or an engineer.