Shields Damp Proofing are experts in making any building safe and secure.
When refurbishing or converting an existing building, underpinning may be required to stabilise and strengthen the foundations.
When a building has been damaged by foundation movement and requires underpinning, there may also be a need to carry out structural repairs or strengthening work to the structure. Such works should be assessed, designed and specified by a structural engineer or a specialist structural repair company like ourselves.
Here are a few reasons why a building may need underpinning:
- foundations that have moved as a result of landslip or unstable slopes
- foundations affected by erosion
- foundations affected by subsidence
- foundations affected by mine workings
- foundations affected by vibration damage
Underpinning is also required when a new building is being constructed adjacent to an exisiting property.
Our specialist team here at Shields Damp Proofing will first of all organise a site visit to assess if the damage is significant, clarify the cause of the damage and make necessary works to make sure the building is made stable and secure. Further investigation will then be made to confirm the size of the problem and the possible solutions to make the building safe.
The most common method of underpinning is traditional mass concrete underpinning – a simple technique that involves excavating a segment of ground below the existing building foundation in controlled stages, to a depth where suitable bearing strata exists.
The excavation is then filled with concrete and allowed to cure before the next ‘pin’ is excavated. To transfer the building load safely to the new pin, a dry sand cement packing mortar is rammed in between the new and old foundation.
This method is low cost and suitable for shallow depth underpinning. Work can be carried out from one side of the wall and in areas of difficult and restricted access. It is suitable for heavy foundation loads and massive structures and for the formation of new cellars and basements beneath existing buildings.
The mass concrete technique cannot be adopted as a solution for all foundation failures. Other techniques will be required to overcome difficulties with groundwater, lose ground or fill. Ensure that the decision to use traditional mass concrete underpinning has been made by a competent person such as an experienced structural engineer.
Where foundation movement has been caused by the removal or decay of a tree for example, the underpinning scheme should incorporate appropriate anti-heave protection.
Call our experienced team today to organise a free site visit on 020 8001 0133