Once you have decided on an insulated patio roof, the next question is how thick the panels should be. Insulated panels come in a range of core thicknesses, commonly from about 50 mm up to well over 100 mm. Thicker is not always better: it changes the heat, the span, the weight and the look of the roof edge, and the right answer depends on your patio.
We use Superior Panel insulated panels. Here is what the thickness changes, and how we choose it with you.
What a panel is
An insulated panel is a sandwich: a profiled steel roof sheet on top, an insulating foam core in the middle, and a flat steel ceiling underneath. The top and bottom skins are pre-painted steel, and you can have a different colour on the ceiling from the roof. The thickness people talk about is the depth of the core.
Thickness and heat
The core is what stops the sun’s heat coming through. A thicker core holds back more heat, so the ceiling stays closer to the air temperature on a hot day. In practice, the biggest jump in comfort is from a single sheet of steel to any insulated panel. Going thicker again gives a smaller, but still noticeable, gain, which matters most on a west or north-facing patio with no shade. The panel maker publishes the thermal performance of each thickness, and we can show you those figures at the quote.
Thickness and span
This is often what decides it. A thicker panel is stiffer, so it can span further between beams. That means fewer beams and posts, a cleaner ceiling and more open space underneath. The panel maker’s span tables set how far each thickness can go for your wind rating, and the engineer checks the design for your site. On a long projection off the house, the span tables often call for a thicker panel, or for an extra beam with a thinner one.
Thickness and wind
Wind lifts a patio roof as well as pushing on it. Most of South East Queensland is N2 or N3, and exposed or hilltop sites go higher. The higher the wind rating, the shorter the allowed span for a given panel, so the same patio can need a thicker panel or more beams on an exposed lot than in a sheltered street.
The look of the edge
The front edge of the panel shows, usually behind the gutter. A thinner panel gives a slim, light roof line, which suits a modern home or a patio fixed under a low fascia. A thicker panel looks more solid, which suits a big patio or a gable. Where the patio meets the house, the panel thickness also affects how much height is left under the roof, which matters on a low house.
Downlights and fans
Downlights and fans fit into the ceiling of an insulated panel, with the cable run inside the panel. The downlight you choose has to suit the depth of the panel, and very slim panels limit the fittings. Tell us your lighting plan before the panels are ordered so we can check the fittings against the thickness.
Rain noise
Any insulated panel is much quieter in rain than a single sheet, because the core damps the vibration. A thicker core helps a little more, but the difference between thicknesses is smaller than the difference between single skin and insulated.
Weight and the frame
A thicker panel weighs more, and the beams, posts and fixings to the house are designed for it. Fixing to an older fascia or a light house frame can limit how heavy the roof can be, which is another reason a flyover or a freestanding patio is sometimes the better choice.
How we choose
- Which way the patio faces and how much shade it gets.
- How far it projects from the house, and whether we want to avoid a middle beam.
- Your wind rating.
- Where and how it fixes to the house, and the height under the roof.
- Your lights and fan, and the look you want at the roof edge.
We bring panel samples in different thicknesses to the quote, so you can see the edge and feel the weight. We then design the patio around the panel that does the job, and the span tables and engineering confirm it before anything is ordered.
Our advice
For a patio you sit under every day in full sun, do not choose the thinnest panel just to save on the roof. For a shaded patio or a modest span, a mid-range thickness usually does everything you need. Either way, it pays to choose the panel and the beam layout together.