How to arrange a drain on a flat roof with greenery?

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I am currently building my own home with a flat roof. This needs to be greened, which I would like to do myself. Most things are clear to me, but there is one place where I am still lacking guidance: how do I deal with our exterior drainage (i.e. the place where a pipe goes through the attic)? I probably shouldn't dump gravel in front of it .... but then do I just leave a gap in the gravel or should I make a partition of L-sections?



Hi, L-profile is overkill. Just planting something in front of it is bad because the roots will eventually constrict or even close the pipe. I would put large river pebbles in the area. You can find them in the hardware store. And the whole thing is then (eg in the spring) revisable and you can clean.


The planting usually does not go up to the parapet anyway, but is e.g. delimited with gravel strips. Influences of course keep free, the roofer delivers anyway.

  • Is there actually already long-term experience with greened flat roofs on EFH? Comes often in B-plans from regulation, but how long does the whole compare to, for example, a classic gable roof? Seems to me (purely from the feeling) as initially more expensive and risky that you have to do it more often and larger within 40 years than with the proven alternative
  • They are two pairs of shoes, a gable roof is sloped, on the roof tiles there is idR 30-year warranty and if it is not damaged, low maintenance. A green roof area is always a flat roof (only low slope possible without effort) and has a higher risk, for example, due to leakage.
  • We have here in the wider neighborhood 2 houses with green gable roof. Looks great. Slope... hm less than 45° in any case.
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