Rainwater pipes

Rainwater downpipes and accessories


Rainwater downpipes are made of NedZink NTZ® and must meet EN 612.

Current dimensions are 80 and 100 mm. The material thickness is 0.65 mm. The Ø 80 mm pipe is often used.

Rectangular pipes are also often used. Thickness is 0,65 mm if one right-angle is = 100 mm. Thickness is 0,70 mm if this side = 100 and < 120 mm. In the case of a right angled side of =120 mm the minimum thickness is 0.80 mm. Standard lengths 2 and 3 metres.

Non-standard prefab rainwater downpipes can be ordered according to drawing via the wholesale trade (length max.3 metres) or made by the metal worker from NedZink NTZ®.

Non-standard prefab rainwater downpipes must also meet EN 612.

The accessories, namely: bends, wreathes, clamps etc. can be ordered as a standard or according to drawing from the wholesale trade or be made by the metal worker from NedZink NTZ®.


The brackets must be adjusted to the rainwater downpipe and are usually made of hot dip galvanized steel.

Attachment of brackets

The brackets must be attached at a maximum of 2 metres distance, and the upper bracket must be installed at least 1 metre under the gutter bottom, see fig. 6. When the movement (expansion) of the gutter is absorbed by bends, the bracket distance to the gutter bottom may be less than 1 metre. The attachment of the bracket must be taken from the instructions of the bracket manufacturer and/or the specifications.

Installation of rainwater downpipes

The rain pipes are hung from above to below. The rainwater downpipes are slipped in to one another with a min. overlap of 50 mm. Each length of piping must be bracketed at least once. The brackets must allow for the expansion of the pipe, and a soldered wreath prevents sagging. The upper short length of piping may not be able to press against the bottom side of the gutter and must therefore have at least 20 mm space. The outlet piece must be slipped at least 50 mm into the downpipe so that the projecting outlet piece must be min. 70 mm in length. See figs. 5 and 10.

Special constructions

If rainwater downpipes do not lead in a vertical line to the sewer, short lengths of piping in staggered line must be led to the lowest point. Use can be made of bends and jumps, or as custom-made work of lengths of piping made in mitre. The corner between an inclined short length of piping and the preceding length of piping may not be smaller than 120°.

The slope of a rainwater downpipe must be minimum 5 mm per metre, if the specifications do not require otherwise.