PortusHouse
Frequently asked questions

Flexible Backyard Living

Ten questions about building a function room in your backyard.

1.Do I need a Council planning permit?
Usually, no. Under Victoria's current rules, a small second dwelling of 60 m² or less on a lot of 300 m² or more, with no triggered overlay (Heritage, Bushfire, Flood and similar) and no reticulated gas connection, generally needs a Building Permit only — no Planning Permit. We run your address through VicPlan for free and give you a straight answer before you commit to anything. If your lot does trigger planning, we tell you up front and quote the extra step.
2.How long does it take, and will my yard become a building site?
Factory pre-fabrication takes roughly 8–10 weeks (as a guide — typical projects can vary with design and council timing). On site, the main module is craned into position in one day, with fit-out, services and handover completed across roughly 2–3 weeks. Because most of the work happens in the factory, the on-site footprint is small and short-lived. You will not have the three-month building-site look of a traditional extension.
3.What does it cost, and what is included?
Pricing depends on the size and the specification you choose, so we price it properly rather than quoting a number off a page.

Included: structure, windows and doors, internal fit-out, kitchenette or kitchen, bathroom, electrical, plumbing, air conditioning, transport and installation.
Not included: site-specific footings or slab preparation, landscaping, decking beyond the standard specification, and any mains service connections where required.
4.Can I use it for Airbnb or short-stay accommodation?
Often, yes — but this is one to check locally rather than assume. Short-stay rules vary between councils, and some areas have introduced permit or registration requirements.

A separate dwelling with its own entrance and its own bathroom is well suited to short-stay use where it is permitted. We will point you at the right check for your council before you design around it.
5.Can it be a home office, studio or gym?
Yes. The same building works as a home office, a studio, a gym, a music room, a treatment room or a guest space — the difference is the fit-out, not the structure.

The one thing to confirm is that the permitted use under your Building Permit still covers how you intend to use it. Tell us the plan at design stage and we will build the right version.
6.Can it be moved if I relocate later?
The building is modular and, in principle, can be lifted and relocated. In practice it is a specialist job with real cost, and it needs the destination to have its own approvals.

Our honest advice: plan it as a permanent building, because that is where the value is. If you genuinely might move it, raise it early and we will tell you what that does to the cost.
7.How good is the sound insulation?
Walls and ceiling are insulated and lined to meet NCC requirements for a habitable dwelling. In normal use, a separate dwelling and the main house do not disturb each other — which is exactly why this arrangement works well when one of them is rented out.
8.Can I get NBN, and is it fast enough to work from?
Yes. You can run a separate NBN connection to the dwelling, or extend the main house connection by mesh Wi-Fi or a hard-wired run.

If the space is going to be a workspace, tell us at design stage and we will run conduit so cable or fibre can be pulled through later. It is a small cost during construction and an expensive retrofit afterwards.
9.Do I need a separate street address? How does mail work?
No separate street number is required. Deliveries can come to the main house address, or you can mount a separate letterbox at the front of the dwelling.

If the space is used for short-stay guests, a key-safe or smart lock at the dwelling entrance is the usual arrangement — guests get access without walking through the main house.
10.Do I need to tell my insurer?
Yes, and you should do it before anyone moves in. A separate dwelling is a separate insurable structure, and short-stay use in particular needs to be disclosed — an undisclosed change of use is the classic way to have a claim refused.

Your broker will typically arrange either an extension of the existing policy or a standalone policy. It is a short phone call; make it early.