Can anyone tell me if there is an appropriate BS, or failing that just a standard recommendation, for how many downpipes a given run of guttering needs? I used to have a 40' run of roof with a downpipe at each end of it, but following an extension I now have a single downpipe at one end of a 60' run of roof, and the builder assures me that is sufficient to cope with the amount of rainwater the complete roof generates. For clarification, the roof has an approx. 30 degree angle and is roughly 20' of roof, from gutter edge to ridge tile (or
1200 square feet of roof for a single standard downpipe which feeds into a soakaway in the garden rather than a main drain). thanks in advance- posted
16 years ago