To make sure I explain it clearly: all the drainage lines are connected to- or go horizontally, straight to the vertical drainege lines, whih their air escape to the roof! Only the toilet bowls have their built in 'traps'.
Is this an accpetable, sanitary, building practice? Is this done because we are in a very hot, humid climate or I'm the victim of a bulding mistake or even of a scam?
Prompt expert's advise is greatly appreciatted, as things are starting to s(t)ink here!.