What are special foundations?
Section 20 of the Act defines special foundations as foundations in which an assemblage of beams or rods is used to distribute a load.
In practical terms, this often raises questions about reinforced concrete foundations and arrangements incorporating reinforcing steel.
However, not every use of reinforced concrete means the foundation is a special foundation under the Act.
The actual construction arrangement and method of load transfer must be considered.
Why does the Adjoining Owner's consent matter?
Section 7(4) requires previous written consent before special foundations can be placed on an Adjoining Owner's land.
This is different from the statutory rights concerning certain ordinary projecting footings.
Under Section 1(6), a Building Owner constructing a new wall wholly on their own land in accordance with Section 1 may have the right to place necessary projecting footings and foundations beneath adjoining land.
Section 1(7) provides for compensation for relevant damage.
However, this does not override the restriction on special foundations.
Because the Act does not authorise special foundations on adjoining land without the required previous written consent, a Party Wall Award cannot simply impose that arrangement on an unwilling Adjoining Owner.
What happens if consent is refused?
If the Adjoining Owner does not consent, the Building Owner may need to reconsider the proposed foundation design.
Depending on the project, alternatives might include:
- Suitably designed mass concrete foundations.
- Eccentric foundations keeping the relevant structural elements within the Building Owner's land.
- Revised foundation dimensions or positioning.
- Other engineered solutions that avoid placing special foundations beneath adjoining land.
Any alternative must be designed and checked by the structural engineer.
The Party Wall Surveyor considers the statutory implications rather than designing the foundations.
What is a Bailey Rail?
The term Bailey Rail is associated with Chaturachinda v Fairholme (2015), decided by His Honour Judge Edward Bailey in the Central London County Court.
The case arose from an appeal by adjoining owners against a Third Surveyor's Award concerning proposed basement works.
The Building Owners proposed a new basement and rear extension.
The engineering arrangement involved a reinforced concrete basement structure supported on unreinforced mass concrete strip foundations.
The Adjoining Owners argued that the mass concrete strips had been introduced to avoid the requirement for consent to special foundations and did not serve a genuine structural purpose.
The court considered the actual foundation arrangement and the function of the mass concrete strips.
On the evidence presented, the mass concrete strips were treated as the foundations supporting the reinforced concrete structure.
The foundations were therefore not treated as special foundations on the particular facts of the case.
The term Bailey Rail subsequently became associated with this type of arrangement, where a reinforced concrete structure bears upon an unreinforced mass concrete strip or rail.
The decision illustrates why the actual structural design matters.
However, it was a county court decision on its own facts.
It does not mean that any reinforced concrete basement can avoid the special foundations restrictions merely by adding a layer of mass concrete.
The structural purpose must be genuine, and the design must be assessed on its own merits.
Foundation arrangements at the boundary
Illustrative diagram — not to scale.
If you are the Adjoining Owner
If your neighbour's drawings show foundations extending beneath your land, it is sensible to establish whether they are special foundations.
Where Section 7(4) applies, your previous written consent is required, and you are not obliged to provide it.
You should understand the proposed construction before deciding whether to consent.
Your appointed Party Wall Surveyor can review the structural information and explain the relevant statutory position.
Is written consent needed?
No
Yes
Specifying mass concrete does not by itself make consent unnecessary.
Why should this be considered early?
Foundation designs are often substantially developed before the Party Wall implications are reviewed.
If the proposed foundations extend beneath neighbouring land and constitute special foundations, obtaining written consent can become an important project constraint.
Early review allows the architect and structural engineer to consider suitable alternatives before the design is finalised.
This is particularly relevant to London basement projects, side-return extensions and other construction close to a boundary.
What should you do next?
If you're proposing foundations close to or beneath adjoining land, send us your structural drawings.
We can review the Party Wall implications and identify any consent issues that may need to be resolved before construction.
If you're an Adjoining Owner concerned about proposed foundations, we can also advise on your rights and appointment options.
If you're an Adjoining Owner, see our Adjoining Owner Surveyor service.
Related guides: What Is a Third Surveyor? · Security for Expenses Under the Party Wall Act · Can You Enter Your Neighbour's Land to Build an Extension?
