Services · Ground improvement · Soil grouting
Soil Grouting: Cement Grouting and Void Filling
Soil grouting means pumping cement-based grout under pressure through drilled holes to fill voids and strengthen the ground. We use it for voids under foundations, water leaks and loose ground.
Material
Cement grout, with admixtures if needed
Types
Permeation, compaction, fracture, void filling
Method
Sleeve pipe or single stage
Use
Under foundations, water cut-off, voids
Standard
EN 12715
Region
Türkiye and Central Asia
What is soil grouting?
Soil grouting makes the ground stronger and less permeable by pumping grout into its voids or cracks. We drill the holes with a small rig and pump the grout at a controlled pressure. Once the grout hardens, the voids are full and the ground holds together.
Unlike jet grouting, soil grouting does not break up the ground. Here the grout enters the existing pores, or it pushes the soil aside to make room. Jet grouting, by contrast, cuts the soil with a high-pressure jet and mixes it with cement.
When do you need soil grouting?
- Voids have formed under a building or slab and settlement has started
- A water leak has washed out the ground and opened voids
- Loose ground needs firming up before an excavation or tunnel
- Water comes into a basement or through a wall and needs cutting off
- Old fill or rubble hides voids below
Types of soil grouting
There are four main types. The ground and the purpose decide which one we use.
| Type | How it works | Suitable ground and job |
|---|---|---|
| Permeation | Grout spreads between the grains | Sand and gravel; water cut-off |
| Compaction | Stiff mortar pushes and densifies the soil | Loose ground; lifting a settled structure |
| Fracture | Grout splits the soil and forms lenses | Fine-grained ground; strengthening |
| Void filling | Fills existing voids and cavities | Under slabs and foundations, karst voids |
In fine sand and silt, cement grains may not fit into the pores. So such ground needs microfine cement or a different grout.
Where do we use soil grouting?
We use grouting most often under existing structures. With a small rig, we can work without emptying the building.
Voids under foundations
Fills voids under a settling foundation and densifies the ground.
Under slabs
Closes voids under factory and warehouse floor slabs.
Water cut-off
Reduces water coming through basements, walls and excavation bases.
Before excavation
Firms up loose ground before tunnelling and excavation.
When an existing building’s foundation needs strengthening, we often weigh grouting together with micropiles and jet grouting. You can read more on our underpinning page.
How do we carry out soil grouting?
We work in five steps. At every point we keep pressure and volume within limits and monitor the structure throughout.
- Hole layout: We mark the grouting points from the design and drill small-diameter holes.
- Pipe: Where needed, we place a sleeve pipe in the hole and fill the annulus with sleeve grout.
- Grouting: We pump grout from the bottom up, one level at a time.
- Limit values: When a level reaches the pressure or volume limit in the design, we finish it.
- Repeat: If needed, we grout a second time through the same pipe.
What we watch most closely on site: heave. Grout pumped at too high a pressure can lift the ground and the structure. That is why we monitor the structure while grouting and stop at once if we see movement.
Quality control for soil grouting
We check quality through grouting records and later measurements. At every point we log pressure, volume and time.
| Check | What it shows | What it does not show |
|---|---|---|
| Pressure and volume record | Grout injected at each level | Exactly where the grout spread |
| Structure monitoring | Heave and settlement | Improvement in the ground directly |
| Check holes and cores | Whether the voids are full | The condition of the whole area |
| Later boreholes or CPT | Increase in ground density | The success of a water cut-off on its own |
What does the price of soil grouting depend on?
We usually price grouting by metres drilled and grout used. However, grout take depends on the voids in the ground, and nobody knows it exactly in advance. That is why our quote gives separate unit rates.
- Number and depth of holes and total drilled length
- Whether the job needs sleeve pipes
- Grout take and admixtures
- Working inside the building and access
- Structure monitoring and check tests
- Mobilisation
What to send for a quote
- Any site investigation and borehole logs
- A description of the problem: settlement, voids or water
- Plan of the structure, foundation details and photos
- Site address and access details
If the cause of the problem is unclear, we first recommend a site visit and a site investigation. A void with an unknown cause can open up again after grouting.
Frequently asked questions about soil grouting
We have grouped the questions we receive by who asks them. If yours is not here, call us or write through the quote form.
Buying and cost
How much does soil grouting cost?
We do not publish a fixed rate, because grout take varies a great deal with the voids in the ground. Our quote gives separate unit rates for metres drilled and for grout; you pay for actual use.
Why is the grout volume unknown at the start?
The volume of voids in the ground only shows during grouting. So the design sets a volume limit for each level, which keeps the cost under control.
Why do quotes differ?
Usually the method and scope differ. For example, sleeve pipes cost more than single-stage grouting, but they give far more control. Line up the method first, then compare the prices.
Project managers and site engineers
Can you grout while the building is in use?
In most cases, yes; we work with small rigs inside and around the building. Still, we separate the area for noise, dust and safety, and agree a schedule with the occupants.
Will grouting damage the building?
Uncontrolled pressure can lift a building, so we limit pressure and volume. We also monitor the building while grouting and stop at once if we see movement.
Can grout leak into the neighbour’s basement?
It can; in open ground especially, grout may travel in unexpected directions. So we check neighbouring basements before work starts and watch them while grouting.
How long does it take?
The number of points, the depth and the grout take set the duration. With the quote we give a programme, and if the take is higher than expected, we update it with you.
Supervising engineers and designers
What records do you keep?
For each point we record the depth, level, pressure, volume and time. We also log the monitoring results from the structure.
What does a sleeve pipe add?
A sleeve pipe lets us grout each level of the same hole separately, and again if needed. As a result, the grout goes exactly where it should, in the right amount.
Which standard do you work to?
For construction we follow EN 12715 (grouting), which Türkiye adopts as TS EN 12715. On public works we also follow the client’s technical specification.
Which grout suits a water cut-off?
In coarse ground, cement grout is enough. Fine-grained ground, however, needs microfine cement or other grouts. The grain size distribution of the ground decides the choice.
Building owners and managers
How can I tell if there are voids under my building?
A sinking floor, sticking doors and windows, or new cracks can all be signs. For a firm answer, however, you need a site visit and a site investigation.
Will grouting stop the settlement?
When voids cause the settlement, grouting often stops it. If the cause is different, for example an inadequate foundation, you may need another solution such as micropiles.
There is a water leak. What should I do first?
First find the leak and have it repaired. If it goes on, the water washes out the ground again and the voids come back. After that, we can fill the voids with grout.
Academics and students
In which ground does permeation grouting work?
It works in coarse sand and gravel, where grout particles can enter the pores. In fine ground the pores are smaller than the cement grains, so the grout cannot advance.
How does compaction grouting work?
A very stiff mortar goes into the ground and forms a bulb without mixing. As the bulb grows, it pushes and densifies the soil around it.
Sources
Request a quote for soil grouting
Send us a description of the problem, the plan of the structure and any site investigation. We will settle the method and a unit-rate quote together.