Taking photographs of cracks so changes can be compared

Why photographs matter before a survey begins

A crack in a wall does not tell its whole story on the day you notice it. It might have been there since last winter, or it might have opened overnight after a dry spell. A structural engineer arriving at your home will ask when you first saw it and whether it has grown. Without records, those questions are hard to answer.

Photographs taken at intervals give a factual account of what the wall has done. They let a specialist compare the width and length of a crack across weeks or months without relying on memory. If the ground under your home is moving because of clay shrinkage or a leaking drain, the pictures show the direction and speed of that movement.

You do not need professional equipment to make these records useful. A phone camera, a ruler and a consistent approach are enough to produce evidence that a surveyor can work with. The aim is to remove guesswork so the right investigation happens first.

Choosing a fixed point and framing the shot

The most common mistake is standing in a slightly different place each time. Even a shift of a few inches changes how wide a crack looks in a photograph. Pick one spot on the floor where your feet will go every time you take a picture. If the crack is high up, note which floorboard or tile you are standing on.

Hold the camera at the same height. Resting it against a door frame or a shelf keeps it steady and repeatable. Frame the shot so the entire crack is visible, plus a hand-width of unbroken wall around it. That surrounding area gives context and shows whether new fractures are branching off the original line.

Take two versions of each shot. The first should be close enough to see the texture of the plaster or brick inside the gap. The second should be pulled back to show where the crack sits in relation to a window, a corner or a ceiling line. Both angles help a specialist reading the images later.

Adding a scale so width can be measured later

A photograph of a crack without something to measure it against is only a picture. Place a steel ruler flat across the opening so the millimetre marks sit over the gap. Press it gently against the wall so it does not cast a shadow that hides the edge of the crack.

If you do not have a ruler, a coin works as a temporary reference. A ten-pence piece is 24.5 millimetres across. Tape it next to the crack rather than holding it, because fingers move between shots. Write the date on a small piece of paper and tape that beside the scale so it appears in the frame.

Make sure the scale is parallel to the wall surface. Angling it toward the camera foreshortens the markings and makes the crack look narrower than it is. Check the screen before you press the button. You should be able to read the numbers clearly when you zoom in on the image afterward.

Lighting, focus and avoiding reflections

Cracks in dark hallways or under stairs often come out as blurred shadows. Switch on the room lights and open any curtains before you start. If the area stays dim, hold a torch to one side of the crack rather than shining it straight in. Side lighting throws a thin shadow along the gap, making its edges sharp.

Tap the screen on your phone to set the focus point directly on the ruler or coin. Cameras tend to focus on the brightest part of a scene, which might be a window behind you. Locking the focus prevents the wall from turning soft while the background stays crisp.

Gloss paint and varnished wood reflect light back into the lens. Move yourself slightly left or right until the glare disappears from the crack itself. You want to see the material inside the gap, not a white flare covering it. Take three frames of each setup and keep the sharpest one.

How often to take new photographs

One photograph proves a crack existed. Two prove it changed. The space between them determines how much you learn. Taking pictures every day produces dozens of identical files and makes comparison tedious. Waiting six months risks missing the point where a seasonal gap became permanent damage. A gap of four to six weeks works well through most of the year. In late summer, when clay soils in Kent shrink fastest, shorten that to three weeks. Read more about [why cracks can look smaller after a wet winter](/blog/why-cracks-can-look-smaller-after-a-wet-winter) if you notice seasonal changes. Keep a notebook or a folder on your phone with the dates. Note anything relevant that happened between visits: a tree was pruned nearby, a downpipe started leaking, or a door began sticking. Those details give a specialist firm the context they need to interpret the images alongside ground conditions.

Storing and sharing the photographs safely

Photos kept only on a phone can be lost to an update or a broken screen. Copy each set to a computer or a cloud folder on the day you take them. Name the files with the date and the room, such as 10-July-kitchen-window. Alphabetical sorting then puts them in chronological order automatically.

When you contact a specialist firm about subsidence, they will ask for these images before arranging a visit. Send the sharpest example from each date rather than the entire folder. Too many files slow down the initial assessment. Include the notes from your diary so the surveyor knows what else changed around the house.

If you decide to sell your home later, having a dated photographic record shows buyers and their solicitors that movement was monitored responsibly. It does not replace a formal structural report, but it answers early questions and demonstrates that the problem was not ignored.