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Self-check

Void filling checker

Work through a short set of questions about the ground, floors and structures at your property. The answers give a first indication of how likely it is that a void has formed below. Only a void survey using probe drilling or ground penetrating radar can confirm what is actually there.

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Could you have an underground void?

Work through a short set of questions about the ground, floors and structures at your property. The answers give a first indication of how likely it is that a void has formed below. Only a void survey using probe drilling or ground penetrating radar can confirm what is actually there.

Has a floor slab, patio or path sunk, or does it sound hollow when you tap it?
Is there a disused cellar, well, tank or old shaft on or near the property?
Has a hole, hollow or sudden dip appeared in the garden, drive or under paving?
Is the property in an old mining area, or does a leaking drain or culvert run beneath or beside it?
Are there new cracks in the walls, doors that have started to stick, or gaps opening between floor and skirting?

Ask about the job to have a specialist confirm the finding on site. This tool gives a first indication only; the real answer comes from an investigation at the property.

What each level means

  1. Low likelihood The signs you have described are consistent with firm ground or movement from another source. Record any changes to cracks or dips over the coming months and arrange a void survey if they develop further.
  2. Possible The combination of signs is worth investigating properly. A void survey will show whether an empty space exists below, how large it is and whether filling is needed.
  3. Worth investigating The signs point to a void beneath or alongside the property. Arrange a survey soon: knowing its size and extent early keeps the repair scope manageable and protects the structure above it.
  • Seasonal ground movement: Clay ground shrinks during dry periods and expands again when wet, which can crack walls and cause doors to stick with no void involved. A survey shows whether the ground is hollow or responding to seasonal moisture changes.
  • Leaking drain: A damaged drain can wash soil away and leave a gap below a slab, but the pipe itself then needs attention. A CCTV drain survey establishes whether water movement is the cause before any filling work is planned.
  • Loose backfill: Ground placed back after a trench or old demolition can settle over years and produce a dip at the surface. Probing the ground first shows whether the issue is a true void or compaction that can be made good.

Get a free quote today

Describe the problem and a specialist covering your area will come back with a clear answer on the cause, the work needed, and the cost.

Send an enquiry
Send an enquiry