A client in Woonona rang about a patio roof. She knew exactly what she wanted: solid Colorbond, colour-matched to the house, running the full width of the back so the table and the barbecue finally had cover. Reasonable request. We'd have built it in about a week.
I went out on a Tuesday afternoon and stood in her lounge room instead of in the yard, which is where I try to start these jobs. The room already sat on the south side of a wide eave and it was dim at three in the afternoon in August. Put a solid roof out from that wall and every bit of remaining daylight coming through the back sliders would have been gone. She'd have gained a covered patio and lost the room she actually lives in.
We built her something else. It's the same conversation nearly every time, so it's worth setting out properly.
Three words people use to mean the same thing
Ask ten people what a pergola is and you'll get pergolas, patios, verandahs and outdoor rooms used more or less interchangeably. On site they mean quite different things, and the difference is mostly the roof.
A pergola is an open structure. Posts, beams, and battens or a lattice over the top. It breaks up the sun and gives the space a ceiling to sit under, but rain goes straight through it and so does a good share of the light.
A patio roof is sheeted. Once you put a solid or translucent sheet over the frame, you have shelter you can use in the rain, and you have made a real change to what the house behind it receives.
A verandah, in the way it's used around here, is roofing that reads as part of the house rather than an attachment to it. It usually picks up the existing roofline and continues it down over the outdoor space, often with a lower pitch. It's the most expensive of the three and the one that looks like it was always meant to be there.
Most people arrive asking for one of these and leave having chosen another, once we've talked about what they actually want to do out there.
The roof is a decision about the rooms behind it
This is the part that gets skipped, and it's the one I'd think hardest about.
Anything you build off the back wall of the house sits between the sun and the rooms on that wall. A solid roof takes light that used to reach the kitchen or the lounge and stops it a few metres short. On a north-facing wall in the Illawarra you might be glad of that in February and quite unhappy about it in July, because the winter sun that used to warm the room is now landing on your new roof sheeting.
There are a few ways to have both, and they're worth knowing before you commit to a material.
Running polycarbonate or a laserlite-style sheet over part of the structure, usually the section nearest the house, keeps a lot of light coming through while still shedding rain. Some people sheet the outer two-thirds solid and glaze the strip closest to the wall for exactly this reason. It looks deliberate when it's set out properly and it saves the room.
Open battens over part of the run do the same job differently: shade in summer when the sun is high, light through in winter when it's lower. It's the same bit of physics that decides whether a new house is comfortable without being heated, and it costs nothing to use when you're setting out the structure.
The other option is to build it clear of the house. A freestanding structure a couple of metres off the back wall gives you a covered spot and leaves a gap for light to drop into the room. It doesn't suit every yard, but where it works it's the neatest answer to the whole problem.
For the Woonona job we ran open battens for the first section off the wall and sheeted the rest. She got a dry table and kept her afternoon light.
Attached or freestanding, and what the fascia can carry
The next question is what holds it up.
An attached structure ties into the house, which usually means bolting a beam to the wall or hanging off the fascia. Fascia brackets are the quick way and they have limits. A fascia board is designed to carry a gutter and finish the roof edge, not to carry half the weight of a new roof plus the wind that gets under it. For anything with real span, or anything sheeted, the connection normally needs to go back to the rafters or into the wall structure, and on a brick house that means through to something that will hold.
Wind is the reason to take this seriously rather than the weight. A sheeted roof is a sail. Uplift on a light roof in a southerly is a genuine load, and it's the one that pulls badly fixed patio roofs off houses. Structures like this are designed and built to the National Construction Code, which the Australian Building Codes Board publishes in full at ncc.abcb.gov.au, and the wind classification for your site is part of it. Blocks up on the escarpment side and out on exposed headlands don't get the same numbers as a sheltered street in the middle of Figtree.
Freestanding costs a bit more in posts and footings because nothing is leaning on the house. What you get back is freedom: you can place it where the yard is nicest rather than where the wall is, you avoid opening up someone's roof, and you don't inherit whatever the last owner did to that fascia.
Where the water goes
Every new roof creates water that used to fall on grass. It has to go somewhere, and "somewhere" cannot be your neighbour's yard.
A sheeted patio roof needs guttering, a downpipe, and a path to your stormwater. On a lot of older Illawarra homes the existing stormwater is already working hard, and adding a decent chunk of new roof area to a line that was sized decades ago is how you end up with water pooling against the house in a heavy autumn. It's worth looking at where the existing downpipes actually run before you add to them, because the fix is far cheaper drawn on paper than dug up later.
Two other things catch people. A structure that sits over an easement is a problem regardless of how light it is, and one that changes the way water crosses a boundary is a problem even if nothing is built on the boundary. Both are worth checking at the sketch stage.
Carports are the same structure with a different problem
A carport is a patio roof over a driveway, structurally speaking. The engineering conversation is the same. The siting conversation is completely different.
With a pergola or patio you're solving for sun, view and the room behind. With a carport you're solving for the car: where the crossover is, how much room you need to swing into the space, whether a post lands exactly where the passenger door opens, and whether the roof is high enough for a roof rack or a ute with a canopy. Get the post positions wrong and you'll live with a daily irritation that no amount of good finish makes up for.
Position is also what usually decides the approval question. Structures in front of the building line, or on narrow and battleaxe blocks where there isn't much room to place anything, tend to need a certificate where the same carport further back wouldn't. I've set out how the exempt, complying and DA paths work for these jobs in the guide to council approval for decks, pergolas and carports. NSW Planning keeps the policies those paths sit under, including exempt and complying development, on its state environmental planning policies page.
Timber or steel, and what's underneath
Timber looks warmer, works with older and character homes, and is easy to detail nicely. It also wants a coat every few years, and around the coast it wants it a bit sooner than the tin says.
Steel is lower maintenance, holds a clean line, and spans further for less depth, which matters when you want fewer posts in the middle of the space. It's usually the sensible answer for a carport and often for a wide patio roof.
You can mix them. Steel where the span is doing the work and timber where you'll see and touch it is a common and honest combination, and it's the sort of thing worth talking through on site rather than picking from a brochure. Our pergolas and carports page covers how we normally put those together.
What's underneath gets less thought than it deserves. If the structure is going over a new deck, the deck's subframe and footings have to be sized for the posts landing on them, not designed first and asked to carry a roof afterwards. Building both at once is cheaper and structurally simpler than adding a roof to a deck that's a year old. If you're at that stage, the decking page and the comparison of merbau against composite boards are the two things worth reading first.
Before you order anything
Stand inside the house at the time of day you most use the room behind, and look at what your new roof is going to take away. Then walk the yard and work out where the water will run once there's a roof where the grass is.
Those two questions decide more about whether you like the finished thing than the material, the colour, or the shape of the beams. Everything else can be sorted once they're answered.
Want a hand with this at your place? Get a free quote or call 0434 037 851.