About this calculator
A complete gutter takeoff: sections, brackets, end caps, outlets, corners and the downpipes with their bends and clips.
How it’s calculated
Each run gets enough outlets that no length of gutter exceeds your maximum per outlet. Brackets go at no more than 1 m centres, with one within 10 cm of every joint and fitting (Marley). Gutters come in 3, 4.5 and 6 m lengths and downpipes in 3 m lengths, and each offset is made from two downpipe bends. The number of drops follows the eaves height.
Worked example
With these inputs:
- Total eaves length
- 30 m
- Separate gutter runs
- 2
- Corners (inside or outside)
- 0
- Eaves height
- 2.6 m
- Max gutter length per outlet
- 12 m
- Gutter length
- 4.5 m
the result is:
- Gutter lengths
- 7 × 4.5 m
- Outlets / downpipes
- 4
- Fascia brackets at 1 m max
- 32
Tips from the trade
- Marley’s PVC gutters can be level or have a slight fall towards the outlet.
- Put outlets near valleys, which dump a lot of water.
- Add a corner fitting for every change of direction.
- Size gutters from the roof area and the maker’s flow tables.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and SANS 10400 (the National Building Regulations) and your local municipality before ordering.