Find out more about unstable soil, the problems it can cause and the process of soil stabilisation.



Unstable soil can be defined as soil that will not stay in place on its own, and therefore requires extra support. It should be noted that unstable soil can threaten the stability, security, and safety of infrastructure and can damage, degrade, and even destroy a number of structures, such as buildings, bridges, and roads. There are a variety of factors that can cause unstable soil including erosion, poor compaction, freeze/thaw cycles and decomposition.

What is the soil stabilisation process?

1. Complete a thorough site evaluation

2. Create a grouting plan and an appropriate grid pattern

3. Lay out the grid pattern and drive in the injection pipes

4. Determine an injection point sequence, based on conditions

5. Inject the resin into each point at the correct pressure and volume

6. Extract pipes, seal drill holes and clean up the site



Bridge Approach Slabs
• Sinkhole Remediation
• Railroads
• Highways
• Driveways
• Loose Sand/Soil

What causes unstable soil?


Poor drainage, improperly placed downspouts, leaking drain pipes, and broken water lines are common culprits.

Poor Compaction

When backfilling on a jobsite, the contractor is supposed to compact the backfill by driving over it with heavy equipment. However, this isn’t always done properly for one reason or another.


Processes of freezing and thawing essentially accelerate erosion processes. Cold weather freezes moisture trapped in tiny cracks. When this water freezes, it expands, subsequently pushing on the rocks and breaking them into smaller pieces. As processes of freezing and thawing continue, rock and sediment are continually broken down.

Biological Decay

Construction trash pits, buried trees, and other biodegradable materials all break down. Sometimes structures are built over these areas.

How does polymer foam help?

Reinforcing Eroded Areas

Polymer foam displaces water and cures into a solid mass reversing the erosion process.

Permeating Soil

AP Soil 600 foam permeates loose soil to create a strong substrate.

Filling Voids Caused by Decay

Polymer foam fills voids before it cures, making it a great solution for instances of biological decay.

AP Soil 600, AP Lift 430 and AP Lift 475 are approved for contact with drinking water (certified to NSF 61-5). That means they can be used anywhere without having an adverse effect on water quality. Having our core products rigorously tested for environmental compatibility is a key component of our commitment to assuring “painless procedures” for customers. Lasting soil stabilization. Alchemy-Spetec structural foams are stronger than crystalline bedrock.

Soil Stabilisation FAQs

We’re here to help! Here you’ll find the answers to the questions we get asked the most about soil stabilisation. If you would like to know more, get in touch for a free consultation.
  • image/svg+xmlimage/svg+xml
    What is the average cost of soil stabilisation?

    Depending on the level of service you’re looking for, soil stabalisation comes in many different forms and with varying price tags. For example, larger amounts of material is required when repairing porous ground conditions such as gravel or soil conditions that have many voids. However, on average prices start from £180.00 per m3.

  • image/svg+xmlimage/svg+xml
    What are the reasons for soil stabilisation?

    Soil stabilisation is often conducted to improve the strength of a soil which may have been found to be in an unstable condition. In addition, soil stabilisation is conducted for engineering purposes and to prevent movement.

  • image/svg+xmlimage/svg+xml
    What is soil stabilisation?

    Soil Stabilisation is the alteration of soil, which my have been found to be in an unstable condition, as a means to enhance its physical properties and make it stable. Stabilisation holds the ability to increase the shear strength of soil and/or control its shrink-swell properties. In turn, this improves the load bearing capacity of a sub-grade and allows it to better support elements as required such as pavements and foundations.

  • image/svg+xmlimage/svg+xml
    How is soil stabilisation done?

    There are an abundance of soil stabilisation methods which include, but are not limited to, grouting, mixing in stabilising materials, electrical stabalisation and more. The methods used to stabalise soil, however, are chosen according to the specific soil under questions and the results desired.

  • image/svg+xmlimage/svg+xml
    What are the advantages of soil stabilisation?

    Other than the most obvious advantages of soil stabalisation which include being able to achieve stable soil for elements such as pavements, embankments, foundations and more, soil stabilisation is known to be a method able to save time, save money, allow works to be conducted in colder months and allow a greater range of builds to be conducted on the soil.


We offer FREE consultations for all projects, so get started and contact us today by Email, LiveChat or Call for an in-house meeting.


We look forward to hearing from you!

45-46 The Arches, Alma Road,
Windsor, SL4 1QZ

0300 030 1822