Vent the kitchen sink/dishwasher drain over the roof?

Hi, it is on the ground floor, yes the sink is in front of the window, outside is directly the terrace.

Hi, it is on the ground floor, yes the sink is in front of the window, outside is directly the terrace.

Yes, we had that constellation (I believe: last year) already once. Back then, the original poster also had a sink in front of the window and concerns that siphon odor from a ventilation wall outlet would blow onto the grill. I think I was able to dispel those, but I didn't find it earlier.

Yes, we had that constellation (I think: last year) already once. Back then the OP also had a sink in front of the window and concerns that siphon odor would blow onto the grill from a wall vent for the ventilation. I think I was able to dispel those concerns, but I didn't find it earlier.

Well, to be honest, I wouldn't have even thought about that ☺️ I didn't know it was possible to ventilate directly to the outside wall. The question is also, if you don't ventilate at all, is that a problem?

The question is also, if you don't do any venting at all, is that a problem?

Poke only one hole instead of two in the lid of a cream cup, then you will see the difference in the uniformity of the flow. Because that's what it's about here: that the air column in the pipe does not create a "quasi vacuum effect."

I didn't know that it is possible to vent directly to the outside wall.

With the emphasis on "directly," yes. Over a short distance, this does not harm the effect of the valve if the pressure equalization (which is actually meant here by "venting") bends 90°. If you still had five meters of pipe after the bend, the desired effect would be weaker (because of the then less favorable ratio of length to cross-section – this is also the main reason for the cross-section of downpipes).