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Townhouse and unit engineering in Hobart
Structural and civil design for townhouses, units and small multi-residential developments: site classification, footings and slabs, framing and beams, retaining walls and stormwater, documented for your building surveyor and checked on site while it's built.
Documented for your surveyor
Drawings, calculations and a Form 35 your building surveyor can rely on.
Fixed quote in 1–2 business hours
Get a fixed quote for your development
Send the architectural drawings or a concept plan, the site address and the number of dwellings.
Fixed quote for your job. No obligation. Or call 03 6146 4747
In short
A townhouse engineer in Hobart designs the structure of a small multi-residential development: site classification and footings, slabs, framing and beams, retaining walls and stormwater. For each project we produce calculations, structural drawings and a Form 35 for the building surveyor, then inspect footings and framing at the stages listed in the quote. Townhouse and unit projects are priced by fixed quote.
- Fee
- Fixed quote per project
- Quote
- Within 1–2 business hours
- You receive
- Calculations, drawings, Form 35, inspections
Stage by stage
What does a townhouse development need from a structural engineer?
A townhouse development needs a structural engineer at every stage, from testing the ground before design to inspecting the footings and frame during the build. This is how multi-residential structural design usually falls on a Hobart project.
| Stage | Engineering | Why it matters in Hobart |
|---|---|---|
| Before design | Site classification to AS 2870, and a landslip check on LISTmap | Dolerite-derived clays are documented as expansive, and a landslip band changes the approval category |
| Concept | Structural advice to the building designer on spans, garages and stacked floors | Garages under living areas need beams or portal frames that shape the plan |
| Documentation | Footings and slabs, framing, beams, bracing and tie-down, retaining walls, stormwater | Bracing and tie-down follow the site's own wind classification, never a single Hobart class |
| Approval | Form 35 with the application for a Certificate of Likely Compliance | The planning permit from council is a separate approval |
| Neighbours | Dilapidation reports before excavation, and design of any protection work | Underpinning or shoring a neighbour's property is protection work that needs a building surveyor |
| Construction | Inspections of footings, reinforcement and framing, then sign-off | The stages are listed in your quote, so the builder can program them |
Need a condition record next door first? See dilapidation reports.
Townhouses or units
Townhouses or units: what changes structurally?
Townhouses and stacked units are designed under different parts of the NCC, which changes the floors, walls and paperwork. Townhouses side by side, separated by fire-resisting walls, are usually Class 1a buildings under NCC Volume Two. Units with one dwelling above another are usually Class 2 buildings under NCC Volume One.
Your building surveyor confirms the classification, and your building designer or architect sets out the fire and sound separation. We design the structure so those walls and floors, and the footings under them, carry their loads. NCC 2022 applies in Tasmania until 30 April 2027, and NCC 2025 from 1 May 2027.
| Compare | Townhouses | Stacked units |
|---|---|---|
| Usual NCC class | Class 1a | Class 2 |
| NCC volume | Volume Two | Volume One |
| Between dwellings | Fire-resisting separating walls, full height | Floors and walls with fire and sound requirements |
| Typical structure | Timber or light steel frame on a slab or footings | Engineered floors, often concrete or a heavier frame |
| Who confirms it | Your building surveyor | |
Hobart ground
Why do Hobart townhouse sites need careful footing design?
Hobart townhouse sites often combine reactive clay, a slope and a tight boundary, and each one changes the footings, walls and approvals. We design for the conditions the site investigation finds.
Reactive clays
Clays weathered from dolerite are documented as expansive in Hobart, with Mineral Resources Tasmania reports on houses in Lindisfarne, Lenah Valley and Taroona. Footings are designed for the measured site class.
Slopes and retaining
A retaining wall over 1.2 m, or over 0.5 m within 1.5 m of a boundary, is no longer low-risk work. Up to 1.8 m it needs a licensed builder and an engineer's design.
Landslip bands
Low-risk work in a landslip band becomes notifiable, and Class 1 work in a High band becomes permit work. Rosetta and Taroona are documented landslide areas.
Council stormwater pipes
In the City of Hobart, building within 1 m of a council stormwater pipe needs the council's consent, so the pipe's position can move the footings.
Stormwater
How much stormwater detention does a townhouse site need in Hobart?
In the City of Hobart, on-site detention depends on how much hard surface the development adds, under the council's Stormwater Management Policy for Development (adopted 27 May 2024).
| Hard surface added | City of Hobart requirement |
|---|---|
| Under 100 m², no change of use | Exempt from on-site detention (not for lot-creating subdivisions) |
| 100–200 m² | 2,000 L tank with 500 L of detention |
| 200–300 m² | 4,000 L tank with 1,000 L of detention |
| Over 300 m² | Site-specific design by a suitably qualified person |
| 500 m² or more of new hard surface | Water quality treatment as well, unless an exemption applies |
City of Hobart policy. Hobart's water quality exemptions include a single dwelling on one lot and subdivisions of five lots or fewer. Clarence and other councils use their own tables, so we check the rules for your council.
Stormwater is plumbing work
Property stormwater beyond the low-risk limit (a 290 m² roof catchment, a 100 mm connection and no on-site detention) is notifiable plumbing work. It must be designed by a licensed designer, with a Form 35 and a council Certificate of Likely Compliance. We design it under the same Engineer – Civil licence. See stormwater and drainage.
What to send for a quote
- Architectural drawings or a concept plan, as PDFs
- The site address, so we can check landslip bands and council pipes
- Any soil report or site classification you already have
- Your program: planning lodgement, building approval or builder's start
You'll have a fixed quote within 1–2 business hours, listing the design, any testing, the inspections and the delivery date. Fieldwork such as boreholes may be carried out with our geotechnical partner ([geotechnical partner]).
More commercial engineering
Often needed on a townhouse site
Site classification & footings
Soil tests and AS 2870 site classification, then slab and footing designs that suit the ground, with a Form 35 for your building surveyor.
Learn more
Stormwater & drainage design
Drainage plans, stormwater reports and on-site detention designs for houses, units and subdivisions, with the Form 35 council needs.
Learn more
Retaining wall design
Engineer-designed block, concrete, sandstone and gabion retaining walls for Hobart's sloping blocks, with the drawings your builder and building surveyor need.
Learn moreFAQ
Townhouse and unit engineering FAQs
Still unsure? Call 03 6146 4747 or send photos for a fixed quote.