I'm building a house and it has a non-standard roof and attic. The roof has 10x10 meters and there are brick walls on three sides, each 1.8 meters high.

Between the walls I will place a roof and all the water will go on the clear side. The roof has an inclination of 8 degrees.

Do I need to vent the attic and how should I do it?

I have been thinking of placing a few pipes in the brick walls, but I'm not sure how exactly I should do it.


1 Answer 1


Yes, ventilation is not just for keeping the wood roof joists from dryrot, but it also keeps the attic dry so condensation does not drip on the attic insulation. Wet insulation looses its insulation qualities.

Here in the U.S., the Building Code requires "cross ventilation" and allows less ventilation if half of the ventilation is in the top half of the attic. So, with your sloping roof, make sure there are vents in the half of the attic that is highest so the warm hot air can escape in the summer.

  • I'm not sure I understand very well. Should I place a pipe lower on one side and as high as possible on the other? Mar 14, 2017 at 15:12
  • Yes, that would give you "cross ventilation" and any air movement (wind) will dry the attic. Be sure to have screens on the pipes to keep the bugs and insects out.
    – Lee Sam
    Mar 14, 2017 at 16:27
  • Should I calculate the pipe diameter in any way or use a gable vent? Mar 14, 2017 at 17:22
  • Vents made for attics, like gable vents, are best. The size should be 1/150th the size of your attic.
    – Lee Sam
    Mar 14, 2017 at 18:11
  • So if my attic is 10 by 11, I would need a hole almost 1 meter wide? Mar 14, 2017 at 19:09

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