Monopitch Roof Water Removal

[PaddyP]

Hi all, 

 

Trying to reach a decision on the best way to remove rain water from two large monopitch roofs.

 

The initial plan from the design stage had been for a metal standing seam roof with all the water coming off at the end. However our engineer has concerns with this:

 

1. Rainwater from a 100m2 of roof coming to one section would be too much. 

2. Not many suppliers are willing to stand over metal roofs at a 5 degree pitch which we have. 

 

Some of the solutions proposed for problem 1so far have been to hide a pitched roof behind the parapet wall or including 3/4 box gutters at intervals going across the roof to reduce the amount of water reaching the bottom downpipes. I am wondering does anyone who have any solutions for this problem?

 

Problem 2 seems easily fixed with an EPDM membrane or another flat roof product. Is metal definitely out of the question at 5 degrees. I would prefer metal due to the longer guarantees. 

 

I have attached elevations below to give you an idea of the roof. 

 

All the best and thanks in advance, 

Patrick 

 

 

Furraleigh House North Elevations.pdf

[Mr Punter]

You could use a zipped standing seam like Kalzip or Rigidal.  They do roofs for huge buildings.  You can just have a big gutter at the back with, say, 3 downpipes.  I have used these on a couple of projects.

 

[Russell griffiths]

I wouldn’t worry about 100m area, I have 170m of standing seam into a 125mm wide deep aluminium gutter and it performs perfectly, it’s all about how many downspouts to get the water away, if you put one at each end you will have trouble, I have 4 outlets over 17m run of gutter. 

 

Its your sheet length that is the problem, as a join might be needed this is what gets tricky at 5 degrees. 

 

@KevinJ is your man to answer this. 

[PaddyP]

Thank you very much for your replies it is much appreciated. 

 

@Mr PunterPunter thank you for those suggestions. I will have a look into those zipped seam systems. 

 

@Russell griffithsGriffiths I would only have a 5 meter run of gutter at the end with a corner window at one corner which makes the engineer a bit apprehensive about the downpipe situation .

 

Our ICF walls are to be clad in corrugated metal so we are hoping to hide any downpipes behind the metal cladding.