How to redirect rain off a roof.
How much rain will my roof latch.
A small roof with a shorter length on the other hand will not collect a lot of water within a short period of time and will work just fine with the minimum roof slope for drainage.
Going with a 6 12 roof slope instead of 7 12 will work slightly better in terms of minimizing the overall wind uplift pressures while also adequately mitigating for any wind driven rain issues and retaining the profile of a true single story structure from the wind uplift mitigation perspective.
An average suburban roof of 200m 2 with such a rain fall can potentially harvest 100 000l of rainwater 200m 2 500mm 100 000l.
Take the dimensions of the footprint of your roof and convert them to inches.
To get an idea how much water the roof of your own house might yield use the rainfall harvest calculator above.
It is not the fault of your contractor and while the delays can certainly be frustrating a contractor who attempts to install a new roof in the rain is going to be compromising the overall integrity of the installation.
To find how much rain you can collect in an average rain year multiply this number by the average inches of rain.
Just multiple the square footage of roof space you have available x 0 6 gallons per square foot per inch of rain and you can see how much water you can collect from each inch of rain that falls.
When you look at the numbers it s surprising how much water you can collect every time it rains.
While this is a normal aspect of roofing and.
It isn t uncommon for an area to collect up to 350mm of rain in just one month even in rural areas.
There are times when it rains especially during big storms that water cascades off of a roof like a waterfall.
Should your roof installation have to be delayed due to poor weather be patient.
So if you have 2 500 square feet of roof available for water catchment and a single inch of rain falls one day we see that.
For example on a 2 000 square foot roof you can collect 2 000 x 0 56 1 120 gallons inch of rain.
So a 50 x 20 roof is 600 x 240 multiply the roof dimensions by the number of inches of rainfall.
Just a half inch of rain falling on a 1 000 square foot roof will yield 300 gallons of water.
To calculate the runoff from any given rainfall.
So then if 100mm of rain falls in a summer week as happens throughout coastal areas of australia then a roof size of 190 6m 2 will yield 19 060 litres of rainwater 100mm x 190 6m 2.
It is important to note that 1mm of rain falling on 1m 2 of wet roof area will yield 1 litre of water.
A wide roof with a steep slope will lead to faster runoff hence necessitating a slightly steeper slope for effective discharge of the rain water.
Keep in mind most rain falls over 2 3 months of a year.
