Pressure Grouting

Pressure Grouting

What is Pressure Grouting and Grout Mixing?

Pressure grouting and grout mixing are associated with foundation stabilisation procedures. The term ‘pressure grouting’ refers to the injection under pressure of a neat cement and water mixture into voids between soil particles. It provides ground stabilisation and increased dynamic / compressive strength of sub soils. Its resistance to water flow and seasonal moisture variations should be high and pressure grouting combined with appropriate steel reinforcing resembles micro piling in certain ground conditions.


Why would I need Pressure Grouting?

The occurrence of foundation deterioration is frequent on a nationwide scale. As a result pressure grouting action was agreed between Insurance representatives and Engineers, as an economical solution to arresting further movement in houses already affected. Accordingly the technique has been used for up to twenty years now and has proven to be a major success.

T.A.L. Construction has completed approximately 3,000 underpinning projects over an eighteen year period using the pressure grouting technique. The pressure grouting technique is so successful that we have not had to return to any of these projects.

When executed in the usual fashion, the pressure grouting process is effective to depths of two (2) metres beneath the foundation top only. There are many other foundation remedial solutions where the ground conditions are unsatisfactory below two (2) metres. These include various types of Foundation Pile & Beam arrangements.


Pressure Grouting Procedures

  1. Expose top of foundation, 300mm by 300mm square (top only). Regular foundation assumed.
  2. Drill through foundations to the required depth (max 2M from the top of the foundation). Extra depths can be achieved in specific circumstances.
  3. Use batching plant to mix neat cement grout.
  4. Use grout pump with 10bar pressure capacity.
  5. Insert grout pipe to the bottom of the drilled hole, choke at foundation level and apply pressure.
  6. After applying a proportion of the gauge, remove the grout pipe half way continue grouting. Finally retrieve the grout pipe to just underneath the foundation and discharge the remainder of the slurry gauge.
  7. If the hole refuses to stay full, a second day of drilling and grouting may be required.
  8. Finally a length of T20 reinforcement bar is dropped to the bottom of the hole (with a safety cap applied to the top).


Contact us for Underpinning: Pressure Grouting

If you are in the public sector, a developer or a contractor, and you are considering working with us in relation to underpinning: pressure grouting and grout mixing, contact us in our Dublin office on 01 6310300 or in our Cork office on 021 4345999.