Hi;
I have some problems in the slope of pipes in the bathroom of soil stack pipes, Really I make 1 cm per meter so I need some helps and correction for my information.

Thank for your help

In the USA a 3" or small pipe needs 1/4" per foot, 4" pipe needs half that or 1/8" per foot. This may help you with te conversion Conversion Tables (http://dershin.com/conversion.html)