Outdoor structures
Carport, pergola and deck engineering in Canberra
A carport, pergola or deck in the ACT skips building approval only if it meets five limits, and planning allows a bigger roof than that exemption does. We design the footings, beams, posts, tie-downs and the connection to your house.
- From $590 + GST ($649 inc GST), fixed before we start
- Fixed quote in under 20 minutes on average, during business hours
- 25 m² of roof, where the full building approval exemption stops
Prefer to talk? Call 02 6189 9876
Or email info@canberrastructuralengineers.com.au
Monday to Friday, 8:00am to 5:00pm
- Engineering onlyWe never sell the repair or the build.
- From $590 + GST($649 inc GST), confirmed before we start.
- Fixed quote in under 20 minutes on averageDuring business hours, Monday to Friday.
- Canberra and the Queanbeyan sideEvery district, plus Queanbeyan, Jerrabomberra and Googong.
In short
Carport, pergola and deck engineering in Canberra starts from $590 + GST ($649 inc GST). A structure needs no building approval only if it has no walls, is up to 3 m high, has a roof up to 25 m², a floor up to 1 m above ground and no span or cantilever over 4 m. We design the footings and framing. Same prices across Canberra, Queanbeyan, Jerrabomberra and Googong.
- Fee
- From $590 + GST ($649 inc GST)
- Quote
- Fixed, in under 20 minutes on average, during business hours
- You receive
- Calculations and drawings for footings, beams, posts and fixings
- Roof area
- Full building approval exemption to 25 m²; planning allows up to 50 m²
- Near a sewer
- Check Icon Water's requirements before you build
- Area
- Every Canberra district, plus Queanbeyan, Jerrabomberra and Googong
Does a carport or pergola need approval in the ACT?
Not building approval, if it meets all five limits for a "small open building". Miss one and it needs building approval, or at best a partial exemption your certifier confirms.
- No wallsYes: next checkNo: other rules apply, ask your certifier
- No more than 3 m highYes: next checkNo: building approval
- Roof no bigger than 25 m²Yes: next checkNo: partly exempt at best
- Floor no more than 1 m above groundYes: next checkNo: building approval
- No unsupported span or cantilever over 4 mYes: no building approval neededNo: building approval
These are the "small open building" limits in the Building (General) Regulation. They cover outdoor decks, carports, pergolas, porches, verandahs and shade structures. Meet all five and the structure needs no building approval (BA).
Every exemption also assumes the work doesn't affect "the structural integrity of any part of a building". That matters when a carport or pergola hangs off the house: the fixing can't load framing that wasn't meant to carry it.
Your certifier confirms which rules apply. The full approval tables, including sheds and garages, are in our guide to carport, pergola and deck approval in the ACT.
Why can planning allow a 50 m² carport when the exemption stops at 25 m²?
Because planning and building approval are separate rules. Planning lets a carport or pergola roof reach 50 m² without development approval, but the full building approval exemption stops at 25 m².
| Carport or pergola | Development approval exemption | Building approval exemption |
|---|---|---|
| Roof area | Up to 50 m² | Up to 25 m² in full; above that, partly exempt at best |
| Walls | No more than 2 | None |
| Height | Up to 3 m above datum ground level, or up to 4 m under a 30° plane | Up to 3 m |
| Floor | Up to 0.4 m within 1.5 m of a side or rear boundary | Up to 1 m above ground |
| Where | Behind the building line and inside the solar envelope | Not one of the five limits |
Above 25 m², a carport or pergola is at best partly exempt under the "large building" limits: up to 3 m high, a floor up to 36 m², a span up to 6 m, timber roof members no larger than 100 x 250 mm, steel no thicker than 4 mm and masonry up to 1.8 m, all built to the code. Outside those limits, it needs building approval. For example, a 40 m² double carport can be exempt from development approval and still need building approval or that partial exemption. Your certifier confirms which applies, and we design to whichever it is.
Does a deck need approval in the ACT?
An unroofed deck needs no building approval if it has no walls, its floor is no more than 1 m above ground, the structure is up to 3 m high and no span is over 4 m. Planning limits are lower near boundaries and at the front.
For development approval, an exempt deck's floor can be up to 0.4 m above datum ground level in the front zone or within 1.5 m of a side or rear boundary, and up to 1 m elsewhere. A balustrade up to 1.2 m is fine behind the building line; none is allowed in the front zone.
High decks are where these limits bite. Off the back of a split-level, or on a block that falls away from the house, a deck floor can sit well over 1 m above the ground. Then it needs building approval, and your certifier needs its structural details. We design the footings, bearers, joists, posts, bracing and the connection to the house.
What if a sewer pipe runs under the carport?
Check Icon Water's requirements before you build. Its carport guidance describes a "zone of influence": "the area below the ground either side of a pipe where the weight of your structure will impact or place pressure on our pipes".
Icon Water's guidance indicates that its approval is needed before building work starts, even where no ACT planning approval is required, and that footings aren't permitted inside the pipe protection envelope. Work in an easement or utility protection space also loses the development approval exemption unless the utility gives written permission.
We don't quote clearance distances: they come from Icon Water's requirements for your pipe. We place or deepen the post footings so their load stays out of the envelope, and give you drawings to show Icon Water and your certifier. More on that in building near sewer and stormwater mains, and the terms are explained in our guide to building near a sewer in Canberra.
What's included in carport, pergola and deck engineering?
Engineering calculations and drawings your certifier and builder can use, from $590 + GST ($649 inc GST). Your fixed quote says if a site visit is needed.
- Post footings sized for your site's soil, including reactive clay that shrinks and swells as it dries and wets
- Beams, posts and rafters in steel or timber, with their spans
- Tie-downs and fixings, which the certifier lodges for a class 10 building approval
- The connection to the house, and a check that the wall or roof framing can carry it
Already built? For a structure that went up without approval, see our unapproved structure assessment ($690 + GST ($759 inc GST)). For a letter about an existing structure, see engineer's letters and certificates ($450 + GST ($495 inc GST)). Every price is on our prices page.
What should I send for a quote?
We're engineers only. We don't sell or build carports, pergolas or decks, and we don't recommend builders, so the design is sized for your structure, not a kit.
- Photos of where it will go, including the wall it attaches to
- Rough sizes: length, width, height and how far it sits above the ground
- A supplier's plan or kit drawings, if you have one
- Where the sewer runs, if you know, and any maintenance hole nearby
What happens next?
Three steps, and you know the price before anything is booked. We cover every district, from Belconnen to Tuggeranong.
Send photos or plans
Use the form above, or our full quote form. Add up to 5 photos or plans.
Get a fixed quote
In under 20 minutes on average, during business hours. It says what we'll design and if a site visit is needed.
Design and drawings
We send calculations and drawings for the footings, framing and fixings, for your certifier and builder.
Often needed with outdoor structures
Every service is quoted at a fixed price before we start. Send photos or plans and we reply in under 20 minutes on average, during business hours.
Unapproved structure assessment
Decks, pergolas, carports, garage conversions and extensions built without approval, assessed by an engineer.
$690 + GST($759 inc GST) See the service
Engineer's letters & certificates
Letters on one structure or element: existing decks and carports, roof framing for solar and heat pumps, tank stands.
$450 + GST($495 inc GST) See the service
Building near sewer & stormwater mains
Footing design that keeps new work clear of sewer and stormwater mains, plus stormwater plans.
$790 + GST($869 inc GST) See the serviceCarport, pergola and deck questions
Something else on your mind? Call 02 6189 9876, email info@canberrastructuralengineers.com.au or send photos for a fixed quote.
How big can a carport be without building approval in the ACT?
A roof up to 25 m² for the full exemption, with no walls, up to 3 m high and no span over 4 m. Planning allows up to 50 m², so a bigger carport can skip development approval and still need building approval or a partial exemption.
How much does carport engineering cost in Canberra?
From $590 + GST ($649 inc GST), fixed before we start. Longer spans, a connection to the house, sloping ground or a nearby sewer main can raise it.
Can I enclose my carport to make a garage?
Not under the carport exemption. Walls take it out of the small open building limits. An enclosed garage is fully exempt from building approval only if it's up to 3 m high, with a floor up to 1 m above ground, a span up to 4 m and a roof up to 25 m².
Can a pergola be attached to the house without approval?
Only if it meets the limits and leaves the house's structure unaffected. Every building approval exemption assumes the work doesn't affect the structural integrity of any part of a building, so the fixing to the house matters. Your certifier confirms.
My deck was built years ago without approval. What now?
Start with an assessment. An unapproved structure assessment, from $690 + GST ($759 inc GST), looks at what was built and what it needs. The approval path is your certifier's call.