28/05/2026
๐๐๐ง๐ง๐๐ก๐ ๐ฅ๐ข๐ข๐ ๐ช๐๐ง๐๐ฅ ๐๐ช๐๐ฌ
This weekโs post is talking about your gutters and downpipes. We thought this one might be of interest after all the rain we've had during May.
You probably take them for granted but gutters and downpipes are a very essential part of buildings. They ensure that the rain on your roof is collected and taken away, so the house is not inundated.
There is another factor โ roof water is required to be taken to a โlegal point of dischargeโ as it is called. This is mostly the street kerb. There is more to this and that has been in other posts, including talking about rubble pits in the backyard, Bandwidth charging to the street kerb.
How much water comes off your roof? Quite a lot. In Brisbane we receive roughly 1 metre of rainfall annually. On a small house with only 100sqm of roof, that equates to 100,000 litres. Which is enough for an average household of water use if you have tanks on acreage.
We can receive a fair proportion of rainfall in a short period. For example, the recent 40 millimetres of rain that occurred within one hour. So, the gutters and downpipes need to deal with a bit of roof water.
When it comes down hard, the rain can overflow the gutters and we recommend using traditional quad gutters that have the outer edge lower than the internal side. The standard is 150 millimetres wide, but we sometimes go for 175. The high sided square-line gutters with slots can fail, being smaller, and if that is your preference we strongly suggest having 50% more downpipes. It is not good if the gutter overflows to the inside through the eaves or even worse into the house if there are no eaves.
Most older houses do not have enough downpipes, and this includes houses up to about 2000. The rule of thumb is downpipes at 8m max centres and draining 40sqm max of roof, preferably 35sqm max. Did you know that going from a 90 dia downpipe to 100 dia increases its capacity by an amazing 25%? Consider bigger pipes!
This post was created by humans!
Peter Latemore and his team are local Building Designers, specializing in Queenslanders, including post-war, amongst all building types. Based in Grange, as Latemore Design, 3356 9051, [email protected], ABN 39 010 895 682. Servicing the inner regions within 12kms of Brisbane CBD. QBCC 1055247.
If you would like to see more projects - https://latemoredesign.com.au/
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