There is an existing retaining wall my neighbour has erected, but I want to level (‘fill’) on my property (other side of existing neighbours retaining wall).

The neighbour (A) who proposes to fill (after obtaining development approval, if required) is responsible for the retaining wall to hold the fill and also has an obligation to ensure the existing retaining wall is not overloaded.  This may require piers to be sunk below the level of the existing retaining wall to maintain its integrity.

 

There is an existing retaining wall my neighbour has erected, but I want to level (‘excavate’) on my property (other side of existing neighbours retaining wall).

The owner (B) seeking to excavate will be responsible for the cost of the retaining wall to support the excavation they caused and also any costs to ensure that the previous retaining wall erected by the adjoining owner (A) is adequately supported.

The existing fill retaining wall should have been built to allow for some excavation on the adjoining property.  Given that after 1994 development approval was required fill if within 600mm of the boundary and greater than 200 mm high [Development Regulation 75(2)(c)], it may be that A may be required to contribute to the costs if an application was made to the court [s.60(3) Development Act 1993 (SA)] .   

Encroachment – My neighbour’s retaining wall is on my property or my wall retaining wall is on my neighbour’s property

The Encroachment Act 1944 (SA) addresses matters of this type.  The Act provides for the adjustment of boundaries where buildings or walls encroach on adjoining land. Under the Act a  ‘building’ includes a ‘wall’ (s. 2), but not a fence [see Encroaching buildings].

An application will need to be made to the court seeking orders rectifying this situation.

Repair to existing retaining wall

Given that a wall structure is classified as a building  and the term ‘construct’ in relation to a building includes repairs and/or alterations (s. 4 Development Act 1993), consideration must be given to whether development approval is needed prior to any work being commenced.

Retaining wall is on one party’s property

A retaining wall erected to support excavation or fill is the responsibility of the party that performed that work.  This obligation binds all future owners (successors in title) of the property.

Under the common law tort of nuisance, the party which has altered the natural land (due to excavation or fill) will be liable to the adjoining neighbour if the neighbour’s property interest in the enjoyment of land is substantially and unreasonably interfered with or if they disturb someone else’s ordinary and reasonable use of the land they own or occupy.

Retaining wall is on the boundary

If the erection of the retaining wall is due to solely to one neighbour affecting the natural state of the land, then the party affecting the natural state of the land is responsible for repairs and maintenance.

Where both parties obtain benefit from the retaining wall, then each party is required to contribute. 

If the erection of the retaining wall is due to the excavation by one party and fill by the adjoining owner, then costs for maintenance are apportioned between the parties to the degree each party altered the natural state of the land.

Retaining wall is built on the adjoining property for the benefit of the neighbouring property

Assuming that retaining wall was built on the wrong side of the boundary, the party receiving the benefit of the support will be liable as they are the sole beneficiary of the support.

Retaining wall is needed but not present

Under common law, the party that has interfered with the natural level of the land (i.e. has withdrawn support) is obligated to remedy the situation.    

Subsequent owners (successors in title) assume the responsibility, where a previous owner has built up or removed soil and are also responsible for the repair or replacement of the retaining wall on their property even if they themselves did not erect or alter the retaining wall.  Furthermore, the party that is suffering the interference has an obligation to mitigate the damage or else their claim may fail. 

In Pantalonev Alaouie (1989) 18 NSWLR 119 Giles J considered the law of nuisance and found “…withdrawal of support from land is an actionable nuisance for which strict liability attaches without proof of negligence.”

Urgent work is required to a retaining wall

The Development Act allows for emergency orders to be made if in the opinion of the authorised officer there is a threat to safety arising out of an excavation [s.69(1)(a) Development Act 1993 (SA)].  This order may require the building owner:

If the order is not complied with, the council can have the work performed and the cost is recoverable from the owner [Development Regulation (2008) SA 75 (4) & (5)].

An owner can appeal the order within 14 days after the order is received by them or longer if granted an extension by the court [Development Regulation 2008 (SA) 75(10)].  Owners will need to make a separate application if they seek to have the obligations of the order stayed. 

In Payne v City of West Torrens [2004] SAERDC 110  an authorised officer identified an unsafe boundary wall and issued an emergency order under section 69 of the Development Act to have the wall demolished.  Mr Payne appealed the order and a variation was made to enable the walls to be stabilized and not demolished.

Where the retaining wall was built by the prior owner of the property

In the case of Thynne v Petrie (1975) Qd.R 260, it was determined that an owner who has failed to take reasonable precautions that has resulted in the subsequent soil collapse causing interference, may be responsible, even though they have sold the property. 

Subsequent owners (successors in title) assume the responsibility that a previous owner has built up or removed and are also responsible for the repair or replacement of retaining walls on their property even if they themselves did not erect or alter the retaining wall.

It is important to note in this above case, the applicant (Thynne) lost their claim because they were bound to do what was reasonable to mitigate their loss.  The applicant initiated the application some 7 years after they first noticed erosion occurring as a result of excavation work previously performed, but they failed to take action to mitigate the damage.