Thursday, 04 September 2014
The underpinning truth
Though underpinning is often seen as a last resort when tackling subsidence these days, there are occasions where you have no other option. But, just because you have to get your house underpinned, it doesn't mean that you are out of options all together. The technologies involved in the underpinning process have developed a great deal in recent years, and there are now a number of different methods and techniques available.
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Traditional mass-pour underpinning involves the excavation of a sequence of sections beneath the existing foundations of an affected structure, down to a specified depth. The local building control specialists should then be called in to inspect the excavations, before each pit is backfilled with concrete. This process is then repeated until the entire affected area has been underpinned.
Screw piles and brackets
Underpinning with screw piles and brackets can be employed where traditional underpinning is too impractical, owing to the need to excavate to an excessive depth, or where a piling rig is unsuitable. Where access is restricted, screw piles and brackets can be installed with only a two man crew or on the arm of a mini-excavator. This underpinning method can be carried out much quicker than the traditional technique, so costs and inconvenience can be reduced.
Pile and beam underpinning
Pile and beam underpinning can be carried out in conjunction with mini-piling processes. It involves the installation of mini-piles to either side of an affected wall, then a subterranean pocket of brickwork is removed so a pre-fabricated steel cage can be installed to span across the two piles. Once the cage is inspected by Building Control, it can be concreted to complete the underpinning.
Cantilever pile and beam underpinning uses a similar approach to pile and beam underpinning, only all of the works are undertaken from the property's exterior. In this way, the removal of internal floors and fixtures is not required so the costs and inconvenience can be substantially reduced. This method can also be carried out in conjunction with screw piling.
Piled raft underpinning is a system used when the whole property has been affected by subsidence. All floors need to be removed and mini-piles need to be constructed, before pockets of brickwork can be taken out for the reinforcement to be placed under an engineer's instruction. After inspection, the modifications are concreted to complete the underpinning.
No matter what type of underpinning work you have had done in the past, or for what reason you had it done, you are likely to have difficulty obtaining underpinned insurance. This is not the case with HomeProtect; we can deliver a competitive online quote for underpinned house insurance based on the risk you face today, not the risk you faced before underpinning was carried out.