Flat-roof patio specialists
Patio type
In Perth, alfresco usually means the recessed outdoor room the builder included under the main roof. It is almost always too small, and it is almost always the first thing owners want to extend.
In short
In a WA build the alfresco is the space already under the main roof. A flat patio off it extends that ceiling out, so the two read as one room rather than a house and an add-on.
A flat roof is the natural way to extend it. It can pick up the existing alfresco ceiling height and carry it outward without any of the geometry problems a pitched roof creates against an existing roof plane.
The result should read as one space, not as a patio bolted to the edge of an alfresco.
Height and finish matched to the alfresco you already have.
Existing slab, thresholds, and where the water goes in a downpour.
Flashed so the new roof and the old one behave as one.
Ventilation for cooking, and somewhere a fan can actually mount.
Specification
Every figure is confirmed at the measure. Extending an alfresco is governed by the existing ceiling height, the slab levels and the wind classification at your address.
Typical tie-in
To the existing alfresco beam or the outer edge of the main roof
Ceiling match
Insulated panel underside matched to the existing lined soffit
Height control
Set at the join first; fall and depth worked back from it
Enclosure options
Cafe blinds, fixed aluminium screens or louvred panels
Services
Gas by a licensed gas fitter; power and lighting by a licensed electrician
Slab
Existing fall continued; dowelled construction joint where the slab is extended
Approval
Building permit, with stormwater sized for the added roof catchment
Free site measure
Tell us the existing ceiling height if you know it. We will measure it properly and come back with real numbers.
On most Perth project homes, the alfresco is a slab area tucked under the main roof, open on one or two sides, with a lined ceiling and often a set of downlights already in place.
It comes with real advantages. The slab is already poured, the ceiling is already lined, and the power is already there.
It also comes with one consistent complaint. At around three by four metres it takes a table and nothing else, which is why extending it is such a common job.
The extension attaches at the existing alfresco beam or the outer edge of the main roof and runs a new flat plane outward from there.
Matching height is the whole game. If the new roof sits below the existing ceiling, you get a step in the ceiling line and a shadow that makes the join obvious from every seat in the space.
So the tie-in gets set first and everything else follows. Fall, depth and beam height are then worked backwards from the height you have to match.
Where a step is unavoidable, it is better to make it deliberate. A clean 100 mm upstand with a shadow line reads as a design decision; a 40 mm mismatch reads as a mistake.
The existing alfresco ceiling is usually flat plasterboard or a lined soffit in white. An insulated panel roof with a flat white underside matches that far more closely than exposed purlins and steel.
It is the single most effective decision available on an alfresco extension. From underneath, one continuous white plane running from the house to the new front beam looks like one room.
Downlight spacing should carry through too. Continuing the existing grid, rather than starting a new pattern at the join, keeps the illusion intact at night.
Where budget rules out panel, a lined ceiling under a single-skin roof is the fallback. It costs more than the panel saved, which is worth knowing before choosing.
Sizes
Starting points, not a price list. How far you can come out off an alfresco depends on the ceiling you are matching and where the water currently goes.
| Size | What it suits | What a patio builder would mention |
|---|---|---|
| Existing 4.0m x 3.0m, plus 3.0m out | What it suitsThe standard project-home alfresco that only fits a table | Worth knowingDoubles the usable area and is the most requested version of this job. |
| Plus 4.0m out and 1.5m wider | What it suitsAdding a lounge zone beside the existing dining area | Worth knowingGoing wider as well as deeper means the tie-in runs past the original opening. |
| Plus 3.0m out with a 100 mm stepped upstand | What it suitsAn existing ceiling too low to match without losing head height | Worth knowingA deliberate step with a shadow line reads as design; a 40 mm mismatch reads as a mistake. |
| Full replacement, 7.0m x 4.5m | What it suitsA water-damaged or awkwardly low alfresco that is not worth extending | Worth knowingBigger job, and it is worth pricing both ways rather than assuming extending is cheaper. |
None of these are fixed. Tell us the alfresco you have and we will tell you what extends off it.
Perth alfrescos get used year-round once the wind is dealt with. The south-westerly that makes summer afternoons pleasant makes winter evenings unusable.
Cafe blinds are the common answer. Clear PVC drops on one or two sides, either crank operated or rope and pulley, and they turn a covered slab into a usable room in July.
Louvred or fixed aluminium screens are the more permanent option. They cut wind and low sun without going fully clear, and they suit modern homes better than blinds.
Fixing points for any of it need to exist in the structure. Adding a blind track to a finished patio is possible, and it is always neater when it was allowed for in the beam.
An alfresco extension is usually where the outdoor kitchen lands, and the services need coordinating before the roof goes on.
Gas for a built-in barbecue must be run and connected by a licensed gas fitter, with proper clearances to combustible surfaces and to the roof above it.
A built-in barbecue under a low flat roof needs particular attention to clearance and heat. Manufacturers publish minimum distances, and a flat ceiling two and a half metres up is closer than people assume.
Power, water and drainage all get easier if they are planned with the frame. Conduit through a post and a stub in the slab cost very little at the right moment.
The existing alfresco slab already has a fall on it, usually away from the house. The new area has to continue that fall or you get water sitting at the join.
Extending the slab is common and needs care at the joint. A properly detailed construction joint, dowelled where required, prevents the two slabs moving independently and cracking the finish.
Surface choice follows use. Porcelain pavers, honed concrete and limestone all appear regularly in Perth alfrescos, and each has a different requirement for the base beneath it.
Whatever the surface, the roof water has to be taken away from it. Downpipes discharging beside a seating area are a nuisance every winter.
Some alfresco extensions turn into replacements. Where the existing ceiling is low, water damaged, or set at a height that makes a decent extension impossible, removing it is the better option.
That is a bigger job, because the alfresco sits under the main house roof. Removing its ceiling means working within the existing structure, and any change to the roof itself needs engineering.
The payoff is a single new space at the height you actually want. It is worth pricing both ways rather than assuming an extension is automatically cheaper.
A flat ceiling two and a half metres above a barbecue traps smoke and heat in a way a high pitched roof does not.
Open sides do most of the work. A cooking zone at the open edge of the patio, rather than tucked into a corner against two walls, clears far better on a still evening.
Where a corner position is unavoidable, an extraction canopy is the honest answer. It needs planning with the roof, since ducting through a panel is not an afterthought.
Perth winters are short and wet, and an alfresco that only works from October to April is half a room.
Enclosure is the main lever. Blinds or screens on the weather side, plus a heater and decent lighting, change how often the space gets used between May and August.
Drainage is the other one. Water dumping off the roof edge at the open side, or blowing in under a blind, is what usually keeps people indoors.
We will match the ceiling height and finish on site, so the two spaces read as one room.
What's included
Written out rather than implied. Matching the ceiling, the flashed join and the levels are all in the price, and anything outside the three columns is quoted separately.
Matching what is there
Comfort
Services
How it runs
Five steps, in that order. The ceiling match is confirmed at the measure, not on the day the sheets turn up.
The height at the join is the number the whole design hangs off. We take it before talking about depth, materials or anything else.
Fall and depth are then worked backwards from that fixed height. Where a step cannot be avoided, we make it deliberate and detail it properly.
The application shows the connection to the existing roof and the revised stormwater calculation. Site coverage gets checked before a depth is locked in.
The new plane runs out from the existing beam at the height already agreed. The test is whether you can see the join from a seat at the table.
Downlights continue the existing spacing, and blind or screen fixings are already in the beam. Then the certification paperwork.
Recognise this
Most alfresco flat patios enquiries start with one of these. If yours is on the list, we have solved it on a Perth house before.
At roughly three by four metres, the builder's version takes a dining setting and leaves nowhere to stand. Carrying it another three metres out is the most common job on this page.
A new roof landing just under the existing ceiling puts a shadow across the join that you notice from every seat. Either match it exactly or step it deliberately, because the middle ground looks like a mistake.
A cooking zone tucked against two walls under a flat ceiling traps smoke on a still evening. Moving it to the open edge fixes most of it, and where the corner is fixed, extraction gets designed in with the roof.
Going deeper
This page is about the extension. Where a question needs more room than that, we have written it up properly.
Why a low flat patio gets hot in Perth and what fixes it: orientation, insulated panels, roof colour, fans, screens and the sea breeze.
Read the guideDo you need council approval for a patio in Perth? The WA building permit process, Class 10a, design compliance, setbacks and timelines.
Read the guideIt prices as a patio. Perth rates are about $200 to $340 per square metre for flat Colorbond and $350 to $600 for insulated panel matched to your existing ceiling. Matching an alfresco adds detailing rather than material, so it is rarely the expensive part.
In WA, alfresco normally means the recessed outdoor area built under the main house roof by the original builder. A patio is a separate roof structure added later. An alfresco extension uses a patio roof to carry the existing space further out.
Yes, and it is the first thing we set. The tie-in height is fixed at the existing ceiling, then the fall and depth are worked backwards from it. Matching the height is what makes the extension read as one room rather than two.
An insulated panel with a flat white underside is the closest match to a lined plasterboard soffit, giving one continuous plane from the house out to the front beam. Continuing the existing downlight spacing across the join completes the effect, particularly at night.
Yes, with proper clearances. Manufacturers publish minimum distances to combustible surfaces and to the ceiling above, and a flat roof two and a half metres up is closer than most people assume. Gas must be connected by a licensed gas fitter.
They work well, provided the fixing points are designed into the beam. Clear PVC drops on one or two sides make a Perth alfresco usable through winter. Fixed aluminium screens or louvres are the more permanent alternative on modern homes.
Depth should follow aspect and use, not a standard size. West-facing spaces need more depth plus screening because low summer sun comes in under any roof. North-facing spaces are the easiest, blocking high summer sun while admitting low winter sun.
Yes. It requires a building permit with engineered drawings and a certificate of design compliance from a registered building surveyor. The added roof area also changes the stormwater calculation, so the extra catchment must be drained to an appropriately sized soakwell on site.
Free site measure
Matching an alfresco needs the ceiling height and the slab levels taken on site. We measure both and quote at no cost.
Book a Measure(08) 6186 7419Tell us what the existing alfresco looks like and we will show you how the new roof meets it.
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Send through the basics and we will arrange a time to measure up. No obligation, no pressure.
Rather talk
(08) 6186 7419Site visits by appointment, including after hours.
