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Deck, pergola and carport engineering in Hobart
In Tasmania, an unroofed deck less than 1 m above the ground below is low-risk work. Higher decks are notifiable, and roofed structures and steep blocks bring wind and footing questions of their own. We design decks, pergolas and carports for Hobart's slopes and winds.
Engineering only
We design and certify the structure. Any licensed builder can build it.
Fixed quote in 1–2 business hours
Get a fixed quote for your deck or pergola
Send a sketch with sizes and the height above the ground, photos of the area and what it attaches to.
From $450 + GST. No obligation. Or call 03 6146 4747
In short
A deck engineer designs the footings, posts, bearers, joists, bracing and fixings so a deck, pergola or carport carries its load and resists wind. In Tasmania, an unroofed deck less than 1 m above the ground below is low-risk work; other decks are notifiable and need a building surveyor. Our designs in Hobart start from $450 + GST, with a Form 35.
- Fee
- From $450 + GST, fixed before we start
- Low-risk deck
- Unroofed and less than 1 m above the ground below
- You receive
- Design drawings, member sizes, footings and a Form 35
The rules
When does a deck, pergola or carport need approval in Tasmania?
An unroofed deck less than 1 m above the ground below, or an open pergola up to 36 m², is low-risk work in Tasmania. Higher decks are notifiable work, and any of these structures in a hazard area moves up a category.
| Structure | Low-risk work when | Otherwise |
|---|---|---|
| Deck | Unroofed and less than 1 m above the surface beneath | Notifiable work: a building surveyor and a Certificate of Likely Compliance |
| Pergola | Up to 36 m² and 3.5 m high, open or shade-cloth roof, no masonry | Your building surveyor confirms the category |
| Gazebo | Up to 18 m² | Your building surveyor confirms the category |
| Carport | Depends on size and the conditions in the Determination | Your building surveyor or council confirms the category |
| Any of these in a hazard area | Not low risk in a landslip, bushfire, flood or coastal hazard area | Low-risk work becomes notifiable |
From the Director's Determination on categories of building and demolition work. Planning rules, such as setbacks or heritage, can apply separately. Your building surveyor confirms the category for your project.
Low risk still has to be built right
A low-risk deck or pergola skips the building surveyor, not the building standards. It still needs footings, spans and fixings that work. And where someone could fall 1 m or more, the NCC requires a balustrade.
Notifiable is not a council permit
Notifiable work needs a building surveyor's Certificate of Likely Compliance, with a Form 35 for the design. Permit work adds a council building permit on top.
What we design
What does a deck engineer design?
A deck engineer designs every part that carries load, from the footings up to the balustrade, so the structure is strong, stiff and stays put in a storm.
Footings
Pad footings, bored piers or screw piles, sized for the load and the ground, and set into rock where it's shallow.
Posts and bracing
Timber or steel posts, with bracing so tall posts on a slope don't sway.
Bearers and joists
Member sizes, spans and spacing, and the timber or steel grade and durability for an exposed position.
Fixing to the house
A ledger fixed to the house frame or slab edge, never to brick veneer, or a freestanding deck on its own posts.
Balustrades
Posts and fixings strong enough for the barrier loads, where the deck is 1 m or more above the ground.
Roofs and tie-down
Pergola and carport roofs held down against wind uplift, from the roof sheets to the footings.
Hillside sites
How do you build a deck on a steep block?
A deck on a steep block needs footings set into firm ground below the loose surface soil, tall posts braced in both directions, and a check that the footings don't load a retaining wall or an unstable slope. On Hobart's hillsides, those three decide most of the design.
- Footings into firm ground. Topsoil and loose slope material can creep. Footings go down to stiff clay or rock, and dolerite is often close to the surface on Hobart's hills.
- Set back from the edge. A footing near the top of a batter or retaining wall adds load to it. We keep footings back or design the wall for it.
- Bracing. A deck several metres up on slender posts needs diagonal bracing or rigid connections to stop it racking.
- Wind and exposure. Hilltop and ridge sites catch more wind, and the site's topography is part of its wind class.
- Landslip and bushfire. A landslip band makes low-risk work notifiable and may call for a landslip report. On a bushfire-prone block, a bushfire hazard practitioner prepares the BAL assessment, and the deck's construction follows it.
These are standard engineering considerations, not extra rules. Your design shows how each one is handled on your site.
Pergolas and carports
Do pergolas and carports need an engineer?
Pergolas and carports need an engineer when they are large, roofed with solid sheeting, attached to the house or on an exposed site, because a solid roof turns wind into uplift. An open or shade-cloth pergola up to 36 m² and 3.5 m high is low-risk work, but a solid roof takes a pergola outside that limit.
Wind lifts a solid roof, and that uplift has to be held down through every connection: roof sheets to purlins, purlins to beams, beams to posts, and posts to footings heavy enough to resist it. Attaching a roofed pergola to the house's fascia or rafters adds load to framing that wasn't designed for it, so that connection gets checked too.
Wind class is site-specific. Tasmania sits in non-cyclonic Region A, and the class for your structure depends on its terrain, shielding and topography. We work it out for your site rather than assume one for Hobart.
Deck, pergola or carport design
For a typical deck, pergola or carport. Steep sites, large roofed structures or a site visit are reflected in your fixed quote.
- Footings, posts, framing and fixings designed
- Bracing and tie-down for your site's wind class
- Drawings your builder can price and build from
- A Form 35 for your building surveyor
What to send for a quote
A sketch with the size and height above the ground, photos of the area and the wall it attaches to, the roof type for a pergola or carport, and what the ground is like: rock, clay or a slope.
Already built
Can an existing deck be certified?
An existing deck can often be certified if it complies, or brought up to standard with a repair we design. We inspect it, check footings, members, fixings and balustrades, and issue a Form 55 where the work meets the rules, from $350 + GST.
Send photos
The deck from below and above, its posts, footings, fixings to the house and balustrade.
Inspect and check
We inspect on site, sometimes exposing a footing, and check the deck against the standards.
Certify or design a fix
A Form 55 if it complies, or a repair design your builder can carry out first. See engineering certificates.
Related services
Often needed alongside a deck
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 more
Form 35 & Form 55 certificates
Form 35 designer certificates with our designs, and Form 55 certificates for assessable items, as-built and retrospective work.
Learn more
Landslip reports
Landslip hazard reports for building in a Landslip Hazard Code band, prepared to AGS 2007 with an AS 1726-2017 site investigation.
Learn moreFAQ
Deck, pergola and carport FAQs
Still unsure? Call 03 6146 4747 or send photos for a fixed quote.