Which diameter for the downpipe?

The diameter of the matching downpipe depends on the roof size and the diameter of the selected gutter. The downpipe can be made thinner, for example, if the water is discharged simultaneously at both ends of the gutter.

Which downpipe for which roof size?

All values ​​are approximate. Who has doubts whether the downpipe is really big enough, just take the next larger downpipe. There are no disadvantages when using too large a pipe.

The roof area, which can be dewatered with the corresponding downpipe, doubles accordingly when using two downpipes. So if you want to install narrow thin gutters and downpipes for visual reasons, there must be more outflows.

  • 60 mm diameter - up to 25 square meters roof size
  • 80 mm diameter - up to 50 square meters roof size
  • 100 mm diameter - up to 100 square meters roof size
  • 100/120 mm diameter - up to 160 square meters roof size

Square pipes can hold more

Similar to the box-shaped gutters, the take-up ratio for the square downpipes is a bit higher. So if you want to be just at the upper limit of the roof area and do not want to attach a second downpipe, a square downpipe is a possibility.

The square tube will be able to hold about ten to fifteen percent more water than a round tube. Unfortunately, the square downpipes are a bit more expensive and can not be found in every hardware store. So you have to weigh again the effort and the additional costs against the cultivation of a second downpipe.

Tips & Tricks

At each downpipe you should install a down tube or an inspection opening at the bottom. You can simply push up the tube later and remove leaves, small twigs and old bird nests.

Although these variants cost a bit more, once you've dug up the pop-up's kink to remove blockages, you're probably going to be annoyed that you've spared that little expense.

Video Board: Focus ST COBB 3