In short
You need a structural engineer when work changes, repairs or relies on the structure: removing a load-bearing wall, underpinning, raised decks, retaining walls above the low-risk limits, extensions, or cracks that need a diagnosis. A building surveyor doesn't design anything. For notifiable and permit work in Tasmania they assess the design, issue the Certificate of Likely Compliance and inspect. Many jobs need both.
Key takeaways
- Engineers design and certify the structure, with a Form 35 for their designs and a Form 55 for assessable items.
- Building surveyors approve notifiable and permit work: they issue the Certificate of Likely Compliance and inspect the stages.
- A pre-purchase building inspector reports on condition. When something looks structural, that's the engineer's job.
- Underpinning, structural repairs, raised decks, bigger retaining walls and pools usually need both an engineer and a building surveyor.
Three different professionals can look at the same Tasmanian house, and their jobs are easy to mix up. A structural engineer designs and certifies the parts that hold the building up. A building surveyor assesses and approves building work under the Building Act 2016. A building inspector reports on a home's condition, usually before a sale. Here's what each one does, and how to tell which you need.
Structural engineer or building surveyor: quick facts
- Designs the structure
- A structural engineer, licensed in Tasmania as Engineer – Civil
- Approves the work
- A building surveyor, for notifiable and permit work
- Checks before you buy
- A building inspector, with a visual condition report
- Engineer's paperwork
- Form 35 for designs, Form 55 for assessable items
- Surveyor's paperwork
- Certificate of Likely Compliance, inspections, completion
- Our fees
- Inspections from $590 + GST, Form 55 from $350 + GST
What is the difference between a structural engineer and a building surveyor?
A structural engineer designs the footings, beams, walls and connections that carry the load and certifies that they work; a building surveyor checks that the whole proposal is likely to comply with the National Construction Code and approves it to go ahead. One designs, the other assesses. A building surveyor won't size a beam for you, and an engineer can't approve their own design.
| Question | Structural engineer | Building surveyor | Building inspector |
|---|---|---|---|
| Main job | Inspect, diagnose, design and certify the structure | Assess building work and approve notifiable and permit work | Report on a building's visible condition |
| Licence in Tasmania | Engineer – Civil, under the Occupational Licensing Act 2005 | Licensed building surveyor | Varies: ask what licence and insurance they hold |
| What you receive | Report, drawings, calculations, Form 35 or Form 55 | Certificate of Likely Compliance, stage inspections, completion documents | A written condition report, often to AS 4349.1 |
| Approves building work? | No | Yes, for notifiable work, and with council for permit work | No |
| Designs a repair? | Yes | No | No |
| Typical trigger | Cracks, structural changes, walls, footings, certificates | Any notifiable or permit work | Buying a home |
Roles under the Building Act 2016 and the Director's Determination (v1.4). Confirm the approval path for your job with your building surveyor.
Building surveyors in Hobart work privately. The City of Hobart points owners to a private building surveyor to find out what approvals their work needs, and many owners engage one through their builder or designer.
When do you need a structural engineer in Tasmania?
You need a structural engineer when the job designs, repairs or assesses the parts that carry load: footings, beams, load-bearing walls, retaining walls and the ground under them. These are the common Tasmanian triggers.
- Removing or altering a load-bearing wall. The Determination keeps load-bearing walls, including bracing, out of minor low-risk renovations (clause 2.0.2), so the beam, posts and footings need a design. See wall removal and beam design.
- Retaining walls above the low-risk limits. Up to 1.8 m, a licensed builder can build one only if it is "engineer designed" (clause 2.3.2). Read the retaining wall rules.
- Underpinning. It is notifiable work, and the Determination notes it may need a site and soil test to AS 2870 and an engineer's design (clause 3.0.4). See underpinning advice and design.
- Decks 1 m or more off the ground, or roofed decks. Only a non-roofed deck less than 1 m above the ground is low risk. See decks, pergolas and carports.
- Extensions and second storeys. New footings need a site classification and footing design, and new openings need beams. See extensions and renovations.
- Cracks, sloping floors and movement. Someone has to find the cause before anyone prices a repair. See our crack and foundation report.
- A landslip hazard band. A landslip hazard report is prepared by a geotechnical practitioner, and an Engineer – Civil licensee can be one. See landslip reports.
An architect or building designer draws the building. When the drawings need a beam, a footing or a wall that standard tables don't cover, the engineer designs that part and signs for it.
When do you need a building surveyor in Tasmania?
You need a building surveyor for any notifiable or permit work: the surveyor assesses the design, issues a Certificate of Likely Compliance and either gives it to council before work starts (notifiable work) or sends it to council for a building permit (permit work). Low-risk work in Categories 1 and 2 doesn't need one, although some low-risk items must be reported to council on a Form 80.
Two exceptions catch people out. If low-risk work needs protection work for a neighbouring property, such as shoring next to their footing, a building surveyor must oversee it. And a licensed building surveyor can assess some minor structural repairs or alterations, such as replacing floor joists, as low-risk work after a documented risk assessment (clause 2.8.1).
Glenorchy City Council describes the rest of the role well: your surveyor can act as the applicant, liaises with council and carries out the scheduled inspections, including a final inspection, before the work is signed off. Our building approvals guide sets out the four categories in full.
Which jobs need both an engineer and a building surveyor?
Most structural work on a house needs both: the engineer designs it and signs a Form 35, and the building surveyor assesses it and issues the Certificate of Likely Compliance.
| Job | Usual category | Engineer | Building surveyor |
|---|---|---|---|
| Underpinning a house | Notifiable (3.0.4) | Diagnosis, design, stage inspections | Certificate of Likely Compliance, inspections |
| Major structural repairs | Notifiable (3.0.3) | Cause, repair design | Certificate of Likely Compliance |
| Removing a load-bearing wall | Notifiable alteration (3.0.1), unless assessed as minor (2.8.1) | Beam, posts and footings, Form 35 | Decides the category, approves |
| Deck 1 m or more above the ground, or roofed | Notifiable (3.1.2) | Footings, framing, bracing | Certificate of Likely Compliance |
| Retaining wall over 1.8 m, or in an easement or landslip band | Notifiable (3.1.3) | Wall design and drainage | Certificate of Likely Compliance |
| Swimming pool and barrier | Notifiable (3.1.8) | Shell design on the site's ground | Certificate of Likely Compliance |
| New house or extension, up to two storeys | Notifiable (3.0.1), or permit work in some hazard areas | Site class, footings, structure | Certificate of Likely Compliance, and the permit if needed |
Clause numbers from the Director's Determination v1.4. Confirm the category for your job with your building surveyor.
Do I need a building inspector or a structural engineer before I buy?
Start with a pre-purchase building inspection, and bring in a structural engineer if the inspector flags cracking, movement, sloping floors, a failing retaining wall or anything else structural. A building inspection is a visual survey of condition, commonly prepared to AS 4349.1. It tells you what's visible; it doesn't diagnose the cause or design a fix.
Our pre-purchase structural inspection starts from $590 + GST. For the full comparison, read building inspector or structural engineer before you buy.
What are Form 35, Form 55 and Form 80?
They are the approved forms that tie the people above together: designers sign Form 35, qualified people sign Form 55, and owners or builders use Form 80 to tell council about some low-risk work.
- Form 35, Certificate of the Responsible Designer
- Signed by each designer, including the engineer, and lodged with the application for a Certificate of Likely Compliance.
- Form 55, Certificate of Qualified Person – Assessable Item
- Certifies an assessable item, such as a geotechnical report or an independent check of work already built.
- Certificate of Likely Compliance
- Issued by the building surveyor for notifiable and permit work, before work starts.
- Notice of Work
- The builder's notice to the building surveyor describing the work to be done.
- Form 80, Notification of Low Risk Work
- Lodged with council when the Determination says a low-risk item must be reported, such as a pre-engineered shed.
We provide Form 35 for our designs and Form 55 for assessable items, including as-built checks, from $350 + GST. See Form 35 and Form 55 certificates.
When to call a structural engineer
Call a structural engineer first whenever the question is about the structure itself. The building surveyor comes in once there's a design to assess. We visit sites across Greater Hobart and review photos and plans Tasmania-wide.
- Cracks are 5 mm or wider, keep growing, or come with sticking doors and sloping floors
- You want to remove a wall and don't know whether it's load-bearing
- A retaining wall will retain more than 0.5 m near a boundary or 1.2 m elsewhere
- Your building surveyor has asked for a Form 35, a Form 55 or an engineer's design
- You have a repair quote, such as underpinning, and want an independent view first
- You're buying and the building inspector has flagged something structural
Not sure? Send photos
Photos or plans are enough for a fixed quote within 1–2 business hours. If the job doesn't need an engineer, we'll say so. Ask for a quote.
Need an engineer?
Not sure who you need?
Tell us about the job. Our fixed quote, within 1–2 business hours, says whether it needs an engineer at all.
Sources
- Director of Building Control, Director's Determination: Categories of Building and Demolition Work, version 1.4. Applies from 12 April 2021. Categories 1 to 4, clauses 2.0.2, 2.1.1, 2.8.1, 3.0.1, 3.0.3, 3.0.4, 3.1.2, 3.1.3 and 3.1.8, Form 80 and protection work
- Building Act 2016 (Tas). Functions of building surveyors (s 30) and duties of designers (ss 43–44)
- Building Standards Tasmania (formerly CBOS), Use of approved Form 35
- Glenorchy City Council, Do I need a building permit?. The building surveyor's role, inspections and the certificate of completion
- City of Hobart, Preparing a planning application. A private building surveyor advises on building approvals
- Standards Australia, AS 4349.1-2007 Inspection of buildings, Part 1: Pre-purchase inspections – Residential buildings