Welcome to underpinning services, we have a team of specialists who offer a solution to your underpinning needs. Our underpinning solutions are ideal for all types of domestic and commercial properties – we are happy to look at any size project.
Underpinning may be necessary for a variety of reasons:
• The building has moved caused by poor soil or changes in the soil conditions (e.g. subsidence has occurred)
• Decision to add another storey to the building, either above or below ground level, and the depth of the existing foundations is inadequate to support the modified building or weight of it
Underpinning issues can often arise in buildings both old and new. The passage of time may cause walls to move and more often than not, the poor quality of the ground beneath the building is the reason.
To strengthen the foundations, building structure, we undertake the process of Underpinning. Excavated soil from beneath existing foundations is replaced with material, usually concrete, in a series of phases that increase the overall depth. Thus, a new foundation beneath the existing one is made.
Types of underpinning we engage:
Mass Concrete Underpinning
Beam and Base Underpinning
Expanding Resin Injection
There are a number of different types of underpinning, depending on the circumstances.
Mass concrete underpinning
Due to its low cost and suitability for shallow depth underpinning, and heavy foundation loads, this is the most common method of underpinning. The ground below the existing buildingfoundation is excavated in controlled stages (or pins). When strata suitable for bearing the weight of the building has been reached, the excavation is filled with concrete and left to cure before the next pin is excavated. Safe transfer of the building load to the new pin is achieved by ramming a dry sand cement packing mortar between new and old foundations. This technique cannot be adopted as solution for all situations, and to overcome difficulties such as groundwater, lose ground or fill, other techniques will be required.
Beam and base underpinning
This is a more technically advanced adaptation. A reinforced concrete beam transfers the building load to mass concrete bases, the size and depth of which are dependent upon prevailingground conditions and the applied loads of the building.
This is most suited to sites with variable ground conditions, restrictive access, or environmentalpollution. It is used when foundation loads need to be transferred to stable soils at considerable depths.
Expanding resin injection
This is a more recent development which is cleaner and less disruptive. It involves the injection into the ground of a Underpinning works must also comply with the Construction, Design & Management Regulations (CDM) 2015, and if the building is adjacent to, or in close proximity to other buildings, then the requirements of the Party Wall Act 1996 may need to be complied with.
Prior to commencement of the work, existing structures will be assessed and trial holes excavated next to existing footings for inspection. Particular attention will need to be given to any below grade facilities, such as sewers, drains, electricity cables, and so on.
It is essential that the structural engineer’s instructions should be followed to avoid excessive undermining of existing foundations or causing further damage to the structure itself. Short sections of excavation can be carried out individually, with the timing of each stage and materials specification will be dependent upon the structural engineer’s design. This work will generally be subject to inspection by our engineer, and the building control body.
structural resin and hardener mix, or strengthening grout, that chemically reacts to expand and compact weak soil, thereby raising and re-leveling a structure.
We can provide:
• Site Survey
• Free Quotation
• Drawings using Autocad
• Project Management