Common DIY Carport Mistakes (And How to Avoid Them)

Common DIY Carport Mistakes (And How to Avoid Them)

After supplying steel carport kits across Australia for more than 24 years, we’ve seen the same avoidable mistakes cost DIY builders time, money, and council approval. Most issues don’t come from poor effort — they come from assumptions made before ordering.

If you want a compliant, long-lasting carport that goes up smoothly, these are the mistakes to avoid.

1. Choosing the Wrong Size or Height

Why this keeps happening

Most sizing problems come down to three things:

• Not accurately measuring vehicles
• Assuming council limits won’t be an issue
• Failing to plan for future vehicles

Vehicle clearance errors

Caravans, motorhomes, 4WDs and vehicles with roof racks need far more height than standard cars. We regularly see carports ordered too low simply because the owner guessed instead of measuring.

What to do instead

• Measure your vehicle height properly (or confirm manufacturer specs)
• Allow clearance for antennas, air-conditioners, roof racks and door opening
• If in doubt, go higher — height is far harder to fix later than width

Future-proofing mistakes

If there’s any chance you’ll upgrade to a larger vehicle, design for it now. Retrofitting height or span later is rarely economical.

Council height limits

Every council has different rules on maximum height and setbacks. Some allow concessions, others don’t.

Practical tip: A private building certifier is often the fastest way to confirm current requirements and potential dispensations.

2. Assuming Council Approval Isn’t Required

Why people assume this

Many owners rely on outdated advice or what neighbours “got away with”. Council rules change regularly, and past approvals mean nothing today.

Why councils differ

Each council operates under different:

• Planning schemes
• Wind regions
• Local development policies

For example, in South Australia, carport applications are assessed by local councils and then referred to state government for further approval.

The real cost of retroactive approval

Unapproved carports are typically flagged quickly. Councils will demand:

• Immediate engineering certification
• Retrospective approval (at a higher cost)
• Modifications — or removal

The biggest risk? Engineering standards may have changed since installation, making compliance extremely difficult or impossible.

3. Installing Posts in the Wrong Location

Setback errors

Posts installed too close to boundaries are a common reason approvals fail. Councils may require relocation even after installation.

Misreading footing and post layout drawings

This is one of the most expensive DIY errors we see.

Once a post is concreted in the wrong place, fixing it is slow, messy, and costly.

Best-practice installation method

• Dig footings
• Place posts without concrete
• Assemble enough of the frame to connect posts together
• Check all measurements and alignment
• Only then concrete the posts

*** Do not install roof sheets or anything that creates wind load at this stage. Brace and prop posts securely while concreting.

4. Ignoring Engineering Drawings

Engineering drawings are not optional paperwork — they are your installation blueprint and your proof of compliance.

Proper drawings:

• Specify exact footing sizes and locations
• Ensure compliance with current Australian Standards
• Confirm wind, load, and uplift performance

This only works if the engineering is done by qualified, registered, insured engineers, with proper internal checks. Shortcuts here create long-term risk.

5. Assuming an Existing Slab Is Sufficient

Why slabs fail structurally

Most residential slabs are:

• ~100mm thick
• Designed only for vehicle weight
• Not designed for uplift or lateral wind loads

Bolting posts to a slab means you’re relying almost entirely on fasteners embedded shallowly in concrete — which is unsafe in high winds.

Why footings matter

Footings:

• Transfer load into the ground
• Anchor the structure against wind uplift
• Are essential for engineering compliance

A slab alone is not structural support for a carport.

6. Buying Based on Price Alone

Imported steel vs Australian steel

This is one of the biggest quality divides in the industry.

Key differences:

• Steel strength (some imports are less than half the strength)
• Coating durability
• Long-term corrosion resistance

Genuine COLORBOND® steel weathers gradually over decades. Cheap imported alternatives often peel, fade, or rust quickly.

Quick check: Genuine Colorbond colours are trademarked — verify names directly on the Colorbond website.

Engineering shortcuts

Low prices often hide:

• Outdated or generic engineering
• Unqualified designers
• No professional indemnity insurance

This puts responsibility — and liability — back on the homeowner.

Long-term risk

Poor steel doesn’t just cost more over time — it creates real safety risks:

• Structural failure
• Storm damage
• Flying debris threatening family and neighbours

7. Not Checking Delivered Materials Before Installation

Common assumptions

• “The driver will know where to unload”
• “Everything will be perfect”

Every site is different. Drivers don’t know your project layout.

Be on site for delivery and direct placement.

What must be checked

Before installation:

• Confirm all components are present
• Check for transport damage
• Verify quantities and lengths

Why timing matters

The longer you wait to report missing or damaged parts, the harder it becomes to resolve. Early checking allows issues to be fixed without delaying your build.

Get It Right the First Time

A well-designed steel carport should:

• Meet council and engineering requirements
• Install cleanly as a DIY project
• Last decades in Australian conditions

Avoid the common mistakes above and you dramatically improve your chances of a smooth, compliant build.

Request a quote or speak with our team today on 1300 011 191 to get a carport designed properly from the start.

Thankyou

Regards, Ashley Fraser (Founder of Excalibur Carports)