Flat roof patio: the Colorbond patio explained, with 2026 prices
BeforeFlat Roof Colorbond PatioA flat roof patio is a steel framed patio with a single sheet of COLORBOND steel roofing laid at a gentle fall. It is the most common Colorbond patio in Australia, and suits anyone who wants solid shade and rain cover for a fair price.
BeforeFlat Roof Colorbond PatioWhat is a flat roof Colorbond patio made of?
The frame is steel: posts, a beam along the front, and rafters or purlins that carry the roof. It is usually bolted to the house fascia or a wall and finished in a COLORBOND colour.
The roof is a single skin of profiled steel sheet. Common choices are:
- TRIMDEK: trapezoidal ribs with a tidy, modern look.
- SPANDEK: square-shaped corrugations, strong and light.
- FLATDEK: a profile with a flat, ceiling-like underside made for patios and carports.
Despite the name, the roof is not dead flat. It falls slightly so rain runs to a gutter. Lysaght rates TRIMDEK, SPANDEK and FLATDEK for slopes as low as 2 degrees.
FLATDEK is worth knowing about. Its underside comes in a high-gloss finish, which Lysaght says can reduce the need for extra lighting or clear roof sheets.
Pros and cons of a flat roof patio
Pros:
- The lowest cost steel roof style.
- Quick to build, with a simple frame.
- Low profile, so it sits neatly under most single-storey eaves.
- Huge colour choice to match your house.
- Very low maintenance.
Cons:
- Runs warm underneath on hot afternoons.
- Louder in heavy rain than an insulated roof.
- Can feel low and closed in on a big yard.
- Exposed purlins unless you choose a flat underside sheet.
Who is a flat roof patio best for?
A flat roof Colorbond patio is the practical all-rounder. It works on brick veneer homes, project homes and older houses alike.
It is a strong fit for:
- Families who want shade and rain cover on a sensible budget.
- Single-storey homes where the patio tucks under the eaves.
- Covering a clothesline, barbecue area or side path.
- Mild and southern climates, where heat underneath matters less.
In hot cities like Perth or Brisbane, pick a light roof colour or consider insulation. On the coast, ask your installer about the steel grade. BlueScope recommends COLORBOND Ultra steel for roofing in severe marine areas, typically 100 to 200 m from breaking surf.
How much does a flat roof patio cost?
Here are our indicative installed prices for a Flat Roof Colorbond Patio, by size and state, including GST.
| Size | WA | SA | VIC | QLD | NSW | ACT | TAS | NT |
|---|---|---|---|---|---|---|---|---|
| 3 × 3 m | $7,500 to $9,000 | $7,500 to $9,000 | $8,000 to $9,500 | $8,000 to $9,500 | $8,500 to $10,000 | $8,500 to $10,000 | $8,500 to $10,000 | $9,000 to $10,500 |
| 5 × 4 m | $8,500 to $10,000 | $8,500 to $10,000 | $9,000 to $10,500 | $9,500 to $11,000 | $10,000 to $11,500 | $10,000 to $11,500 | $9,500 to $11,500 | $10,500 to $12,000 |
| 6 × 4.5 m | $11,500 to $13,500 | $11,500 to $13,500 | $12,500 to $14,500 | $12,500 to $15,000 | $13,500 to $16,000 | $13,500 to $16,000 | $13,000 to $15,500 | $14,000 to $16,500 |
Flat Roof Colorbond Patio, indicative installed prices including GST, attached, rounded. Updated 28 October 2026.
Size, height, footings and slab, access, council fees, engineering and removing an old patio all move the price. These figures are indicative only, and a site measure and written quote sets the real number. Our patio cost guide compares every style.
Colours and options
COLORBOND steel comes in 22 core colours, plus 6 colours in a Matt finish: Surfmist, Dune, Shale Grey, Bluegum, Basalt and Monument. Many people match the patio frame to the gutters and choose a lighter roof.
Popular upgrades:
- A flat underside sheet for a cleaner ceiling.
- Clear polycarbonate sheets mixed into the roof for light.
- LED strip lights or a ceiling fan.
- Outdoor blinds on the weather side.
- A raised or stepped beam for more headroom.
See our Colorbond colours guide for combinations that suit common Australian homes.
Do you need council approval for a flat roof patio?
In many cases, yes. Most councils look at size, height, setbacks from boundaries, and whether the patio attaches to the house.
Some small, low patios are exempt or fast-tracked in certain states. Others need a building permit and engineering. Check your state's rules in our council approval guide.
Flat roof patio vs similar styles
Flat roof vs skillion patio
A skillion patio is a single slope too, but steeper and often tilted up away from the house. That adds height and lets winter sun in. A flat roof is cheaper and lower; a skillion looks more modern.
Flat roof vs insulated patio
An insulated patio swaps the single sheet for a foam core panel. It costs more, but it is much cooler and quieter, with a finished ceiling. If you will use the patio daily in summer, compare both quotes.
Want to see how a flat roof Colorbond patio looks on your home before calling anyone? Upload one photo to our free tool and you will see it in about 30 seconds.
Common questions
Is a flat roof patio actually flat?
No. It has a gentle fall so rain runs to the gutter. Common steel profiles used on patios, such as TRIMDEK, SPANDEK and FLATDEK, are rated for slopes as low as 2 degrees.
How much does a Colorbond patio cost?
Our indicative installed price for a 6 m × 4.5 m flat roof Colorbond patio is $11,500 to $13,500 in WA and $13,500 to $16,000 in NSW, including GST. Size, height, footings, access and council fees all move the final quote.
Are flat roof patios hot underneath?
A single steel sheet does get warm on summer afternoons, especially in darker colours. A lighter roof colour helps, and an insulated panel roof is the upgrade if you want a much cooler space.
What is the best Colorbond colour for a patio roof?
Most people match the house roof or gutters for the outside, and choose a light colour like Surfmist for the underside to keep it bright. COLORBOND steel comes in 22 core colours plus a Matt range.
Can a flat roof patio be built near the coast?
Yes, but ask about the steel grade. BlueScope recommends COLORBOND Ultra steel for roofing in severe marine areas, typically 100 to 200 m from breaking surf, and stainless steel closer than that.
Keep reading
Sources
- FLATDEK® flat underside roofing for patios and carports
- TRIMDEK® | Lysaght.com
- SPANDEK®
- Colours | COLORBOND® steel
- Specifying for marine and industrial environments (updated)
Prices on this page come from Backyard Mate's pricing for each state and are indicative only. Rules and products change: check with your council and installer before you build.