Basement extension case law: Chaturachinda v Fairholme

A matter of doubt

16 March 2016

Matthew Hearsum discusses the legal issues arising from a recent case involving basement extension work 

The decision in Chaturachinda v Fairholme [2015] was welcomed as removing the restriction on reinforced underpinning in basement extensions. However, there are a number of reasons why this is not actually the case and the restriction remains. Basement extensions are usually formed by underpinning the party wall between two adjoining properties. Reinforcing the underpinning is a popular choice because the tensile strength of the steel rods that are used allows the concrete to be substantially thinner than a mass concrete alternative, which in turn means that there is greater space in the new basement.

Special foundations


Underpinning a party wall is subject to the Party Wall etc. Act 1996. Section 7(4) provides:

'Nothing in this Act shall authorise the building owner to place special foundations on land of an adjoining owner without his previous consent in writing'.

Special foundations are defined as:

'foundations in which an assemblage of beams or rods is employed for the purpose of distributing any load'.

The starting point, therefore, is that an owner wanting to construct a basement may only use reinforced underpinning with the prior written consent of the owner of the adjoining property.

In Chaturachinda, the design was unusual; the basement slab rested on a mass concrete rail rather than the more usual ‘basement box’ design. The building owner argued that the foundations were not special foundations according to the meaning of section 20; instead the mass concrete rail was the 'foundation' and the reinforced underpinning was only a wall, in which case the adjoining owners’ consent was not required.

The third surveyor agreed, making an award permitting the works without the adjoining owners' consent. The adjoining owners appealed to the county court, which listed the question of whether the underpinning was a 'special foundation' as a preliminary issue.

The court found that the reinforced underpinning was not a 'special foundation' because:

  • the mass concrete rail was the foundation, and not the underpinning
  • to be a special foundation, it must transfer load to the adjoining owner's land, which this design did not.

It has been said that, following this decision, a building owner can avoid the restriction on special foundations by putting a pad or blinding of mass concrete beneath the underpinning.

In fact, the court expressly rejected this approach:

'neither such a pad or blinding layer will protect the Building Owner from the Adjoining Owner's veto in section 7(4) … the proper legal construction in these circumstances will be that neither pad nor blinding layer constitute a foundation independent of the reinforced installation which will itself comprise the basement foundations'.

Therefore, in most cases the building owner will still require the prior written consent of the adjoining owner. Only in a limited number of cases, where the mass concrete

'foundation’ is a permanent part of the design and provides a permanent and considerable level of support, will the restriction on special foundations not apply'.

Distribution of load

The court also considered whether distribution of load could be regarded in deciding whether a foundation constituted a 'special foundation'. The court found that one can only look at whether it is distributing load to the ground on which the wall rests

'and cannot therefore extend to the distribution of load to ground which is not ground on which the wall rests'.

The court went on to say that in the case of a special foundation:

'there must still be a distribution of load to the land of the Adjoining Owners'.

 With respect to the learned judge this must, in my view, be wrong in law. The definition of special foundations refers to 'distributing any load'. The use of the word 'any' without restriction gives it a very broad meaning and – again, in my view – certainly does not support the narrow interpretation suggested by the court.

This decision also does not support the idea that reinforced underpinning may be used more widely; in fact, the opposite is true. The court expressly rejected the practice of putting an unnecessary pad of mass concrete beneath the underpinning to avoid the restriction on special foundations. Moreover, as seen above, the guidance given in the case on what is a special foundation is likely – in my view – to be wrong in law.

So the position is still uncertain. It may be that in the not-too-distant future another adjoining owner may brave the Court of Appeal, where this much-debated issue may be resolved.

Matthew Hearsum is Senior Associate, Solicitor-Advocate and Arbitrator at Morrisons Solicitors

Further information