Rainline Assembly Instructions

Rainline Assembly Instructions


Measure the roof area

​Measure each roof part by multiplying the roof length with the roof width

  • ​If the area is less than 50 m2 use gutters with 100 mm width and pipes with 75 mm diameter.
  • If the area is between 50-100 m2 use gutters with 125 mm width and pipes with 87 mm diameter.
  • If the area is larger than 100 m2 there are gutters with 150 mm width and pipes with 100 mm diameter or 190 mm gutters and 111/120 mm pipes.

If there are different roof sizes on the same building the largest roof part is dimensional.

Calculation of effective roof area

Chart A


Roof Pitch


Effective Area


Flat Roof


Width x Length*


300 Pitched Roof


Length of gutter run x rafter length* x 1.29


450 Pitched Roof


Length of gutter run x rafter length* x 1.50


600 Pitched Roof


Length of gutter run x rafter length* x 1.87

*Rafter Length = Measurement from eaves to ridge

Chart B


Gutter Size


Outlet Installed at End of Run


Outlet Installed Central to Run


Recommended Downpipe Size

































*For buildings greater than 2 stories we recommend an 87mm diameter downpipe be used.

For outlets placed within 2m of bend of above roof areas should be reduced by 15%. If gutter is laid without a fall above roof areas should be reduced by 15%.

Number of brackets and drain pipes

Number of brackets and drain pipes 
  • Calculate how many brackets you need for each roof part (example 10 m/0,6 m +1 = 18 brackets).
  • The brackets should be mounted with c/c 600 mm.
  • The end brackets are mounted 100 mm from the roof edge.
  • Each drain pipe covers maximum 10 m gutter fall (length of the house).
  • The inclination of the gutter towards the down pipe should be at least 2.5 mm/m.
  • Place pipes on each corner of the house for aesthetic reasons or if the gutter fall exceeds 10m.

Transport, storage, unpacking

  • Ensure roof drainage components are handled with care during transport, storage and unpacking.
  • The coating may be damaged or the pipes and gutters dented if not handled correctly.
  • Store pipes and gutters on a plane and stable surface.
  • Non-coated components must be unpacked and stored in a dry and ventilated place.



Gutters and pipes should be cut with plate shears or a hacksaw on a firm underlay on the ground. Never use an angle-grinder. An angle-grinder heats the steel up and therefore destroys the galvanization and there is also a risk of the coating being scorched by hot chips or filings.



To prolong the lifespan of the roof drainage system if the coating has been damaged, paint it with Lindab’s repair paint. Use a sponge or Lindab’s paint nib.


Give the system an overhaul a couple of times a year if you want to keep the roof drainage system in mint condition. Clean leaves and twigs from the gutter and pipes. Wash with water and a mild detergent. Don’t use a high pressure washing appliances.



Lindab’s roof drainage system can be mounted with ordinary hand tools like pliers, hammer, hacksaw, screwdriver, folding rule and string. You will need a bracket bender for bending brackets.



​Use fasteners for fastening the brackets and the pipe holders. We always recommend that you use stainless screws and the correct screws intended for each material. Check if the façade is wood, concrete or bricks as the pipe holders are mounted on the house facade.