Hairline cracks under 1–2mm are often cosmetic, caused by temperature or minor shrinkage. Larger cracks, especially diagonal, stepped, or widening cracks,  are usually structural and linked to subsidence or foundation movement.

You should seek professional help if cracks:

• Are wider than 5mm

• Spread quickly

• Form a zig-zag or stepped pattern

• Are linked with sloping floors or sticking doors

• Appear around windows and door frames

These usually signal active ground movement.

Not always, but subsidence is one of the most common causes of progressive cracking. A professional assessment can determine if the ground has dropped, shrunk, or lost support.

Common early symptoms include:

• Hairline cracks that widen over time

• Gaps forming in cornices or skirting

• Uneven or sloping floors

• Doors and windows jamming

• Cracks appearing suddenly after heavy rain or drought

Yes. If movement continues, cracks typically widen, lengthen, and multiply. They never fix themselves and often accelerate after weather changes, drought, or rain events.

In most cases, yes, but any structural cracks or cracks caused by subsidence should be inspected. While rare, severe movement can compromise wall stability over time.

Yes, resin injection stabilises the ground, re-levels sunken foundations, and stops further movement. It treats the cause of cracks, not just the crack itself.

The most effective solution is to stabilise the foundation using methods like Teretek® resin injection, which restores soil strength and re-levels the home. Only after stabilisation should cracks be repaired cosmetically.

Absolutely. Reactive clay soils expand during wet periods and shrink in drought, causing homes to lift, twist, or sink,  leading to cracking both inside and outside the home.

Most resin injection and re-levelling projects take just a few hours. Larger homes or severely affected areas may take a full day.

Yes,  it is designed to be long-lasting. Once the ground is stabilised and compacted, the foundation regains uniform support.

Costs vary based on the severity of movement, foundation type, soil conditions, and the amount of lifting required. Mainmark provides a detailed assessment before quoting.

Yes. Stabilising and lifting the home can often close or reduce the cracks significantly, especially if the movement occurred in a concentrated area.

No. Some cracks form from minor shrinkage or temperature changes. But significant cracks — diagonal, stepped, widening, or repeated cracks — usually point to sinking or unstable ground.