Gutter recommendation for metal building

[kfickler]

Hey all,

I have a metal building in need of gutters. 50' wide x 80' foot long, and I would prefer to only have downspouts on the corners. 2 of the people I asked to bid it said that 2 downspouts on an 80' run is not enough, that I should use 3, but the middle one will dump right into the area I am trying to dry up. Looking at a 5" gutter with 3"x4" downspout. I guess I could go to a larger gutter, but the cost jumps up considerably.

Any thoughts would be greatly appreciated.

Thanks

 

[bg71361]

kfickler, I have a 30x70 with 5" gutters and the big down spouts. I only have one down spout on each end. Works fine with no problems.

Good Luck,
Bill G.

 

[N80]

On my cabin I have a span of 40 feet served by one downspout. Roof is metal. The gutters handle the water flow fine. Problem is that they are the cheap metal gutters you get from a homestore. They leak at every seam. They should be outlawed. Hope to get seamless ones soon. Installed by a pro.

 

[scott_vt]

Hey all,

I have a metal building in need of gutters. 50' wide x 80' foot long, and I would prefer to only have downspouts on the corners. 2 of the people I asked to bid it said that 2 downspouts on an 80' run is not enough, that I should use 3, but the middle one will dump right into the area I am trying to dry up.

Any thoughts would be greatly appreciated.

Thanks

Afternoon kfickler,
I have to agree with those contractors telling you that 2 downspouts are not enough. We just put an addition onto our firehouse, 75 ft span. We used 3 downspouts and tied them into the perimeter drains along the footer so as not to washout at ground level. I also believe we used the larger size downspout but will have to check on that. I would think that if you have a lower lying area in the near vicinity that could work in your favor.

BTW the drains are tied into a catch basin and then runs off the property.
Oh one other thing the roof goes back about 75' to the peak.

 

[MarEng]

I have a 40x60' with three downspouts per side (4x4.5" necked immediately into 4"DWV) feeding into our rainwater collection system. I have never seen it where I thought the system was being overloaded despite being in East Texas with regular Tropical Storm type downpours.

I've made a career out of asking the question, "What's the worst that can happen?" In your case, the gutter might overflow during a once a year or once every other year turd floater type event. In that case, any water caught coming off the roof will be blessing. The rest of the time, two will handle everything, no problem. Further, the worst that happens is you add another downspout later and some buried pipe to lead the water somewhere else.

I don't really see a downside to trying two first.

Edit - I have the Mueller gutters - added later. If I ever have another barn built I will do the gutters as part of the package while the scaffold is here.

 

[schmism]

id go with a 6" gutter and the larger size downspout 4x5? 2 at the corners should be fine...

if got "normal" gutter on my 32x60 and only downspot on one end... (i didnt put it up.....) it doesnt really work but thats because theres virtually no fall in the gutters.

 

[capt jack]

It WILL work. My side business away from the fire dept. (we all have one) for 26 years is seamless rain gutters. you need 1 sq. inch of downspout drain area for each "square" of roofing (a square = 100 sq. ft.) . Two 3"x4" downspouts = 24 sq. inches of drain area, "if" the outlet holes cut into the bottom of the gutter are also 3x4. An 80 ft. long barn that is 50ft. wide should have a roof area on each side of aprox. 80ft. x 27ft. (assuming a 2/12 or 3/12 roof pitch). 80x27 = 2160 sq. ft. of roof per side, (2) 3x4 downspouts should carry 2400 sq. ft. of roof drainage, so you are at the upper limits of what it will carry. This is for an average rain. Like the other post said, the worst that can happen is a little overflow, if you put a spout in the middle (and don't pipe it out) there will always be water there. Make sure the metal roof does'nt extend over about 1-11/2" over the gutter. Good luck.
Jack

 

[kfickler]

Wow! I wish I could get this must positive input to questions at work!!

Thanks for all the replies. I will post an update after a big storm.

Happy Easter all!