|Sizing Roof Drains for Green Roofs (and All Roofs In Fact) is Important|
Right away I will say that I am not qualified to design roof drains. Sizing roof drainage is a function for a qualified architect or engineer, not a green roof plant person. However, I still worry.
Living in Florida I have seen some heavy and prolonged downpours. Last night in fact, across the panhandle area of western Florida, rainfall totals reached almost 24". That is a lot of water to move off the roof.
Of course storms dumping huge quantities of water do not happen every day. But I still want my green roofs to drain. Most green roof plants do not like 'wet feet' so to speak and I certainly do not want the green roof plants to float off the roof.
Yes, I ultimately trust most architects and engineers on their designs for they are accomplished professionals. But for those occasions, like last night I feel better after a second opinion.
Now I am not vouching for their accuracy, but there are several easy to use Roof Drain Sizing calculators published across the internet. It only takes a few seconds once you have the approximate square footage of the roof you are wondering about to see just how many roof drains are needed for different areas of the country.
Do not use these for design, but like last night, when I was wondering if the architect got the design right, these sites may be a good second opinion.
So stop worrying and check out some of these Roofing Drain Sizing Calculators: