Two complaints come up again and again about older patios: the roof is so loud in a storm that you cannot talk under it, and on a cool morning it drips on the outdoor setting even though it has not rained. Both come down to the same thing: a single thin sheet of steel between you and the weather.
Why a single sheet is loud
A single skin roof is one sheet of Colorbond steel on purlins. Rain hits it and the sheet vibrates like a drum skin, and the open space underneath carries the sound. In a South East Queensland summer storm that is a lot of noise. Hail is louder again.
An insulated panel is a sandwich: a steel roof on top, an insulation core in the middle and a steel ceiling underneath. The core damps the vibration and absorbs much of the sound, so rain on an insulated roof is a soft patter rather than a roar.
Where condensation comes from
Condensation is water from the air, not a leak. On a clear night the roof sheet loses heat to the sky and gets colder than the air under it. When warm, moist air touches the cold underside, water forms on it, just like on a cold drink. By morning it runs down the sheet and drips off the purlins.
- It is worst on clear, still nights in autumn and winter.
- It is worse under a patio that is enclosed with blinds or walls, because moist air is trapped.
- A spa, pool, pot plants or a barbecue under the roof add moisture.
- It is rare on an open carport with good air flow.
How insulated panels avoid it
With an insulated panel, the ceiling you see is separated from the cold roof sheet by the insulation core. The ceiling stays close to the air temperature underneath, so moist air does not condense on it. That is why we rarely hear about drips under an insulated roof, even when it is enclosed.
If you want single skin
Single skin is still the right roof for many carports and for a flyover with plenty of air flow. If it is going over a sitting area, these help:
- An anti-condensation backing on the underside of the sheet, which holds moisture until it dries off.
- Good air flow: open sides, or a flyover that lets warm air out between the two roofs.
- Enough fall so any water that forms runs to the gutter rather than dripping.
- Keeping the area open rather than enclosed with blinds overnight.
Fall and the gutter
Every roof needs enough fall for its profile, as set by the sheet maker, so rain runs off quickly. We use LYSAGHT sheeting and Superior Panel insulated panels and set the fall to their requirements. Too little fall means water sits in the laps, and in heavy rain it can back up at the gutter.
Heat goes with it
The same core that stops noise and condensation also stops heat. A single sheet in the summer sun radiates heat down onto you. An insulated ceiling stays close to the air temperature, which is why an insulated patio feels so much cooler on a 35-degree day. If the patio faces west or north, that is usually the deciding factor.
Fixing an old noisy patio
If you have a single skin patio that drums and drips, the options are:
- Replace the roof sheets with insulated panels on the existing frame, if the frame and footings can carry them. An engineer checks this.
- Replace the whole patio, which is often the better answer on an old, low or undersized structure.
- Add a ceiling under the existing roof, which helps with drips but less with noise and heat.
We can look at your existing patio and tell you which makes sense.
The short version
If you will sit under it, especially in the rain or in the evening, choose insulated. If it is a carport, or an open flyover where you mostly want shade, single skin does the job. We bring samples of both to the quote so you can see and feel the difference.
Enclosed patios
Closing a patio in with blinds, glass or walls traps the moist air from cooking, a spa or pot plants, and that is when a single skin roof drips the most. If you plan to enclose the patio, now or later, choose an insulated roof from the start and leave some way for air to move.