Underpinning costs in 2023 vary depending on the type of underpinning method used. As a starting point, typical costs for the traditional methods of underpinning are £1,500/m2 for mass concrete, and £2,600/m2 for the piling process.
Cost for beam and base piling on average is £2,000/ m2. For the more modern alternative to underpinning, a resin injection process typical costs1 sits around £1,200/m2.
These are only average and the exact cost for the traditional underpinning of residential properties, and commercial structures, will vary depending on many factors, including the size and type of property, the width, depth and condition of the foundations, and if underpinning is required where subsidence has already occurred, the scale of that subsidence. As a rough indication, the cost of underpinning an average 3-bedroom semi-detached house will be in the region of £12,500.
As well as the costs for the underpinning process, there could be additional costs to consider. These may include hiring a structural engineer, at around £50 to £90 per hour, to carry out inspections, give guidance on the most appropriate method to use and to prepare any documents required for Building Control. Planning permission may also be required at a cost of around £462 as will the payment of a Building Control application, where fees can vary between £150 to £250. If a property has a party wall, or walls, and the neighbours don’t consent to the work being done, a party wall agreement will need to be drawn up. This could cost as much as £1,000 per neighbour.
Other factors to consider are the level of disruption that could be experienced with each method and the timescale required for the underpinning process to be completed.