Why Does Outdoor Concrete Sink?

Void in concrete sidewalk

Soil washout can result in empty space beneath your concrete slab, unable to support it. This can lead to cracks and sinking over time.

Concrete is heavy! When the soils underneath a concrete slab are unable to support its weight, the slab will sink.

If part of the concrete slab is supported by soils and other sections are not, the unsupported pieces may crack away from the other section and result in unlevel concrete.

Advanced Basement Systems can inspect the condition of your concrete slab during an on-site estimate. Call us today to schedule a free quote in Chatham, London, Sarnia, Windsor and surrounding areas.

Primary causes of sinking outdoor concrete

    1. Soil Shrinkage, Compaction & Settling

      A hoofprint in the mud, showing compacting soils

      Different types of soil have different load-bearing capacities. When a soil's load-bearing capacity is exceeded, the soil will compact and settle.

      It's also possible for the soil beneath a slab to settle and compact of its own accord. Soil that contains large amounts of clay and/or silt will shrink substantially when it gets dry.

      As the soil compacts underneath a concrete slab, the unsupported slab will sink as well, usually cracking in one or more spots.


  1. Washout Of Soils

    Water washing away mud and sediment in rainy weather.

    The soil that is underneath your driveway, patio, or concrete steps may not necessarily remain there to provide adequate support for the concrete element.

    As water moves underneath your concrete slabs, it can wash away the soil that's supporting the weight of the concrete. As this happens, it creates a void, or empty space, underneath. Over time, with nothing to support it, your concrete slab can begin to sink or cave in.

Looking for a price? Get a no cost, no obligation free estimate.

our service area

We serve the following areas

  • Aylmer
  • Beachville
  • Bright
  • Burford
  • Burgessville
  • Cathcart
  • Clear Creek
  • Courtland
  • Delhi
  • Eden
  • Embro
  • Erieau
  • Fingal
  • Harley
  • Harrietsville
  • Hickson
  • Innerkip
  • La Salette
  • Langton
  • Morpeth
  • Mossley
  • Mount Elgin
  • Mount Pleasant
  • Norwich
  • Oakland
  • Otterville
  • Plattsville
  • Port Burwell
  • Port Rowan
  • Port Stanley
  • Princeton
  • Salford
  • Scotland
  • Springford
  • St George Brant
  • St Thomas
  • St Williams
  • Straffordville
  • Teeterville
  • Tillsonburg
  • Turkey Point
  • Union
  • Vanessa
  • Vienna
  • Vittoria
  • Wallacetown
  • Walsingham
  • Waterford
  • Wilsonville
  • Windham Centre
Our Locations:

Advanced Basement Systems
23576 Prince Albert Road
Chatham, ON N7M 5J7
1-226-706-2439


Advanced Basement Systems
199 Exeter Rd Unit E
London, On N6L 1A4
1-226-270-8565
Coverage Area: Southwestern Ontario