# Forum Home Renovation Pergolas, Gazebos, Strombellas & Rotundas  Pergola roofing

## Nic vdB

i have just joined this group.  I have a question please.  When building a pergola, can I run the roof into the existing gutter on the house, and if so, what angle is required for the pergola roof - i read somewhere here that is a minimum of 5 degrees, but how far out does the angle get measured?  If, for example, I have a 2.5 metre wide roof on the pergola, is it 5 degrees at the 2.5 metre mark, or is it 5 degrees 1 metre out etc?  Thanks   nic

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## cherub65

5 deg is the slope of the roof, you can measure any where along the length. 5 deg = 87.5mm height per 1000mm run, so if you measure out 2000mm vertical it would be a height of 175mm

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## stevoh741

5 degrees is for corrugated. If you want less trimdeck goes to 2 degrees for memory, but why would you want to go that flat?

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## cyclic

> i have just joined this group.  I have a question please.  When building a pergola, can I run the roof into the existing gutter on the house, and if so, what angle is required for the pergola roof - i read somewhere here that is a minimum of 5 degrees, but how far out does the angle get measured?  If, for example, I have a 2.5 metre wide roof on the pergola, is it 5 degrees at the 2.5 metre mark, or is it 5 degrees 1 metre out etc?  Thanks   nic

  You can run the new roof into the existing gutter but the existing gutter may not be able to take the extra water, also, the look from beneath the roof, imo, will not be good. 
Not only that but when it comes time to renew the gutter the pergola may have to be removed just to get to the gutter, so do it right the first time and remove the existing gutter and refit it, or new gutter, at the outer edge of the pergola thus allowing the pergola roof to butt close up under the existing roof with a flashing hence all water runs to the outside of the pergola so any overflow is not as troublesome. 
Corro (custom orb) roofing can be run at 2 or 3 degrees provided the battens are no more than 750mm apart and you don't walk on the roof between the battens hence buckling the roof down and causing rain to pond on the sheets.
Disclaimer...5 degrees is manufacturers recommendation. 
Degrees of roofing are..... 5 degrees 1 in 12 ie 1mm in 12 mm, 100mm in 1200mm, 1metre in 12 metres etc
                                      3 degrees 1 in 18
                                      1 degree  1 in 60
and as already mentioned, measured at any point ie if you want 5 degrees on a 2.5 metre long sheet then the roof will need to rise 208mm which can be substantial when building a pergola and this is why most flat style pergola roofs are quite flat ie 2 or 3 degrees.

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## Nic vdB

Thanks Guys 
Great advice, and much appreciated. 
I think I will take cyclic's advice and run the roof out from the existing gutter and put guttering on the outside of the pergola roof. 
nic

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