Given that we will all shortly be emerging from a state of hibernation, I thought it would be an opportune time to remind you of some of the potential pitfalls in development projects from an engineering and land surveying perspective.

When considering infill development, it is critical that you engage appropriately qualified and experienced professionals.

Infill Developments

Only following completion of a full feasibility of a particular site will the development potential of the site be reliably known. Your land development professional will work with your nominated housing company or architectural designer to assess what can be accommodated on the site.

The planning controls of the District or Unitary Plan will largely dictate the design controls.

These details are usually required by any lending agency that you may be working with to fund the project. Many of the local authorities’ District and Unitary Plans have relaxed their controls, to allow higher intensity development to occur within our urban centres.

Coastal Land

There are geotechnical hazards that are normally associated with coastal land, which purchasers need to be aware of. Steep coastal cliff sites, which are popular for expensive houses, are also subjected to an additional force, that being coastal erosion by wave action.

Properties located on coastal cliff lines are subject to a greater risk of slope instability than properties located elsewhere, due to the risk of cliff line regression occurring. The increased risk to any building can, however, be mitigated by appropriate foundation design, taking into account the various factors affecting cliff line regression.

My advice to anyone considering purchasing coastal land, is to engage a suitably qualified and experienced geotechnical engineer to undertake a prepurchase assessment.

Excavations Near Boundaries

Sloping sites can create challenges when undertaking building development works. Typically, earthworks are undertaken on sloping sites to create level building platforms and/or suitable accessways or carpark areas. These earthworks can result in permanent batter slopes, which need to be designed/constructed to a safe batter angle, so as to prevent erosion or instability of the batter slopes.

If you are undertaking building works on your property, you are legally required to ensure that the works do not result in damage to land or buildings on neighbouring properties. Building works, which includes the construction of retaining walls, are subject to the requirements of the Building Act 2004.

It you are undertaking building development works which involve excavations close to boundaries, my advice to you is to engage appropriately qualified and experienced professional engineers to provide earthworks design recommendations and to design any proposed permanent retention structures.

It is recommended that advice also be sought as to an appropriate construction methodology and the stability of temporary (during construction) excavation slopes.

We always advise our clients to also undertake a condition survey of any neighbouring sites, prior to undertaking any excavation works.

Property Boundaries

While a fence, hedge or driveway may look as though it defines the edge of a property, the actual boundary can be quite different. In many areas the boundary pegs may be missing or severely damaged. If the boundary pegs are not obvious, it may be prudent to have them located or replaced before any design, development or building development works commences.

The consequences of not correctly identifying boundaries when undertaking developments, can be costly to rectify. On a flat, newly developed subdivision, the average builder can generally set out the proposed building location, using the boundary pegs and a locally defined height datum point.

However, the set out becomes increasingly difficult when the pegs are missing, the property and/or building are not the usual rectangular shapes, or the land is steeply sloping. To mitigate the risk of your development not being built in the correct place, you should engage the services of a licensed cadastral surveyor, particularly when the building works are in close proximity to site boundaries.