The design of Eaves, Boundary and Valley gutters on pitched roof metal clad buildings is based on the British Standard code of practice BS6367. This code of Practice provides advice on the best methods of designing gutters, gutter outlets and rainwater pipes along with advice on materials and construction techniques. The performance of the gutter and the capacity of the outlet to discharge water freely is particularly important with internal gutters where overflow into the building would be unacceptable under the prescribed operating conditions. The basis of the hydraulic and practical design principles assumed in the code are summarised as follows:-

• The Gutters are assumed to be laid nominally level.
  
• The Gutters are uniform in cross section being of a box or trapezoidal shape.
  
• Frictional effects on discharge are disregarded for certain outlet conditions.
  
• Weir overflows are recommended to internal gutters.
  
• Overflow of gutters in storm situations is not critical in externally mounted Eaves gutters.
  
• Strength of the gutter must be considered should it be needed to provide walkway access for maintenance in service.

In terms of construction, Valley and boundary wall type gutters are manufactured from galvanised steel not less than 2.0 mm thickness and profiled to wrap around the steel supporting purlins. In the roof construction process these gutters are the first component of the roofing process to be laid and provide a natural access method along the building perimeter. Normally for the gutter to function as a walkway it should have a minimum overall width of 300 mm for boundary and 500 mm for valley gutters.

The starting point for any gutter design is to correctly estimate the amount of water falling onto the roof. Rainfall rates vary throughout the country and are recorded on a statistical basis. The code of practice outlines a process, estimating the rainfall intensity, dependant on geographical location and the risk of the intensity being exceeded during the life of the building.

Typical Applications

Components

Custom Made Profiles

Any practical shape of gutter can be produced, limited only by material girth. Gutter sections are supplied in standard module lengths of 2950mm and incorporate a standard joggle joint.

Typical Dimension Range

Standard Joggle Joint