Telecoms Design for Multi-Dwelling Projects: Duplex to Townhouse

Ask most NSW builders about telecommunications on a duplex or townhouse project and you will get a shrug: “the sparky runs a conduit, doesn’t he?” Sometimes that is true. More often, it is how projects end up with an occupation certificate delayed because there is no compliant lead-in, no NBN application on record, and no way to get four townhouses connected without cutting a brand-new driveway.

Multi-dwelling developments – dual occupancies, duplexes, villas, terraces and townhouses – sit in an awkward middle ground for telecommunications. They are too small to have a project manager chasing utilities full time, but too complex for the single-dwelling assumption that “the NBN is already in the street” to hold. This article explains what telecommunications infrastructure these projects actually need, how the design scales from a duplex to a large townhouse site, and how to keep the NBN process from becoming the last, most annoying item on your completion checklist. It is written from the delivery experience of Pit and Pipe, the telecommunications design consultancy within the Rouse Hill–based Contrive group.

The rule of thumb: every new dwelling needs fibre-ready facilities

Under the Australian Government’s telecommunications-in-new-developments policy, developers – and on small projects that usually means the builder – are responsible for providing fibre-ready facilities for every new dwelling, unit or lot they create. A knock-down rebuild of a single house can often reuse the existing lead-in. The moment you create additional dwellings, you are creating additional connections, and each one needs its own compliant pathway from the street network to the building.

That pathway is passive infrastructure: conduits, pits where required, building entry provisions and first-point-of-entry arrangements. NBN Co brings the fibre; you provide the route it travels. For multi-dwelling projects the design question is not whether you need it, but how much of it, and in what configuration.

How the design scales with project size

Dual occupancy and duplex

For a two-dwelling project fronting an existing street, the infrastructure is usually modest: a lead-in conduit from the existing street pit (or a new pit if none is suitably located) to each dwelling, or a single lead-in to a shared point with internal distribution. The design must still meet NBN Co’s specifications – correct conduit size (typically P23 for lead-ins), bend radii, cover depths and draw rope – and the project still needs an NBN New Developments application so each dwelling is recorded, serviceable and able to order a connection at completion.

The most common duplex mistake is forgetting the second lead-in entirely, because the site “already has NBN”. It has one connection. Your project needs two.

Villas and townhouses on a shared driveway

Once dwellings sit behind others on a common access way, the infrastructure starts to look like a miniature subdivision: a lead-in from the street network, then a reticulated run of conduits (and pits where run lengths, bends or junctions require them) along the driveway, with an individual lead-in branching to each dwelling. The design has to coordinate with everything else fighting for space in that driveway corridor – stormwater lines, sewer junctions, electrical consumer mains, gas and the driveway pavement profile itself.

This is the scale at which a designed, documented solution stops being optional. Pit placement needs to survive vehicle loads or be located out of trafficable areas; conduit depth needs to survive driveway construction; and every dwelling needs its entry point positioned to suit the internal cabling plan.

Larger townhouse estates and community title schemes

On larger multi-dwelling sites – a dozen or more dwellings, internal roads, staged construction – the telecommunications design becomes a genuine network design: distribution conduits (P50/P100), jointing and hauling pits, lead-ins to every dwelling, and a clearly designed connection point to NBN Co’s external network. These projects typically follow the full pit and pipe pathway: application, service plan or master plan, NBN design review, construction to specification, compliance certification and transfer of the network to NBN Co before fibre is hauled.

Staging matters here. If you are building in two stages, the network architecture should let stage one become ready for service without waiting for stage two’s civil works – otherwise your first settlements are waiting on trenching at the far end of the site.

Inside the building: entry points and internal pathways

Telecommunications design does not stop at the wall. Each dwelling needs a building entry provision and an internal pathway to wherever the network termination device will live. On attached forms – duplexes, terraces, manor houses – decisions about shared versus individual entries, riser locations and the position of communications enclosures are much cheaper to make on the drawings than on site. Class 2 buildings (apartments) bring additional requirements again, including communications rooms and riser design, which is a topic in its own right.

Good practice for townhouse projects is simple: show the telecommunications entry and internal conduit route on the architectural and services drawings, in the same coordination pass as electrical and hydraulic services. When the group’s architects at ARQI and the civil team at Contrive Consultants are working on the same project as Pit and Pipe, that coordination happens as a matter of course – the conduit route is on the drawings before the slab is designed, not marked up in texta after it is poured.

The NBN process for multi-dwelling projects

The process mirrors the subdivision pathway, scaled down:

• Eligibility check and application. An online eligibility check with NBN Co, then a New Developments application covering all dwellings in the project. The builder or developer applies, or nominates a representative – commonly the telecommunications consultant – to lodge and manage it.
• Assessment and agreement. NBN Co assesses the application, confirms any charges that apply, and issues its approval documentation. Progress is then tracked through the NBN New Developments Portal.
• Design and review. For small projects this may be a simple service plan; for larger ones, a full pit and pipe design submitted for NBN Co review against its new-development design standards.
• Construction and certification. Conduits and pits installed with the civil works, inspected progressively, and certified. Design compliance and as-built compliance certification is the evidence councils and certifiers rely on.
• Handover and ready for service. Ownership of communal pit and pipe transfers to NBN Co where applicable, fibre is hauled, and dwellings become serviceable – meaning purchasers or tenants can order a retail service from day one.

The single most valuable thing a builder can do is lodge the application early. On a townhouse project, telecommunications lead time is comfortably absorbed if the application goes in around construction certificate stage. Lodged at practical completion, it becomes the item everyone is waiting on.

Common multi-dwelling pitfalls

• No application lodged. The development simply is not in NBN Co’s system, so no one can order a service. Discovered, invariably, by the first resident.
• One lead-in for four dwellings. Retrofitting individual pathways after landscaping and driveways are complete means saw-cutting, boring or trenching through finished work.
• Pits in driveways without trafficable covers – or pits positioned where the swept path of vehicles tracks straight over them. Coordinating with the traffic engineers (our colleagues at Sweptpaths) avoids both.
• Conduits installed too shallow under driveway pavements, failing inspection or failing in service.
• Clashes with stormwater. On tight sites the OSD tank, pipe runs and communications conduits all want the same corridor. Resolve it in design, not in the trench.
• Certification left to the end. If no one photographed or inspected the conduits before backfill, proving compliance later is slow and sometimes destructive.

What it means for your program and budget

Telecommunications on a multi-dwelling project is not expensive relative to the works around it – the conduits share trenches that are being dug anyway, and the design cost is small against the cost of delayed occupation certificates or retrofit works. The economics only go bad when the work is unplanned: separate mobilisation to trench after the site is finished, redesign because the as-built layout cannot be certified, or settlement delays while an eleventh-hour NBN application grinds through assessment.

Treat it like any other engineered service: design it once, coordinate it with the civil and architectural documentation, install it with the main works, certify it progressively. On that footing it is one of the smoothest approvals in the whole project.

Frequently asked questions

Does a dual occupancy really need an NBN application?

Yes, in almost all cases. You are creating an additional dwelling that needs its own serviceable connection, and NBN Co’s new-developments process is how that dwelling gets registered and connected. The existing house’s connection does not cover the new dwelling. The application is straightforward for small projects, but it needs to be lodged – ideally early in construction.

Who is responsible on a small builder-developer project – me or the owner?

The developer entity is responsible for providing fibre-ready facilities, and on small projects the builder frequently acts as the developer’s agent (or is the developer). Practically, whoever controls the civil works needs to own the task, because the conduits must go in with the trenching. You can nominate a consultant such as Pit and Pipe to lodge and manage the NBN application on your behalf.

Can I just run one conduit and split it inside the site?

Each dwelling needs a compliant pathway to the network, and the configuration – shared trunk with individual branches, or individual lead-ins – depends on the site layout and NBN Co’s design requirements. A shared single conduit with no designed branching is the classic non-compliant shortcut. Get the configuration designed before trenching; it usually costs no more to build correctly.

When in the project should the telecommunications design happen?

Alongside the civil and stormwater design, before your construction certificate. That timing lets the conduits share trenches, keeps pits out of driveways and swept paths, gets the NBN application moving early, and means the compliance certification is a formality rather than an investigation.

Talk to the Contrive group

Pit and Pipe (pitandpipe.com.au) designs and certifies telecommunications infrastructure for duplexes, villas and townhouse projects across NSW, working alongside the Contrive group’s civil, stormwater, traffic and architectural teams in Rouse Hill. See the group’s full services, or contact us to get your project connected – call +61 497 848 111 or email info@contriveconsultants.com.au.