Hi gang.
Quick question. Can I get away with one downspout for a 42′ run of gutter? The roof draining into it is 42′ X 16′(rafter length) and is a 5 pitch…. if that helps.
Would that require a remarkable noticeable pitch in the gutter? Seems to me you wouldn’t need a whole lot of pitch in the gutter even at 42′ assuming the gutter is kept clean. But then again, I really don’t know much about gutters, do I?
A second downspout would have to drain in an area very close to our walkout basement door, which has a tendency to take in water during heavy downpours as it is. Best solution would be to pipe it out to a drywell in the backyard, but that ain’t happening right now.
Replies
A lot depends on how fast it rains where you are. An inch of rain on a square of flat roof is about 63 gallons of water, so figure that you need to move at most 425 gallons per inch of rain. The faster that rain comes, the bigger the gutter and downspout you need.
-- J.S.
Hi Diesel,
Although two drops are better than one on 42', you could get away with it. I would recomend though that you get a 6" gutter, and use a 3x4 leader. As I understand it, you are draining almost 7 square. A standard 2x3 leader will only handle up to 6 square of roof, a 3x4 will handle up to 12 square. ( This is what I was taught I havent seen it in writing) Also , ask your gutter guy to use a 3" drop tube (he may refer to it as a cup), this way, the water gets out of the gutter as fast as possible. Hope this helps
Eric