Hi guys i need some advice have built my extension but now the utility room has not got an outside wall for me to take the waste out of. the extension will have a suspended wooden floor. Can i run a 4 inch soil pipe under this floor and up into the utilty room so i have mini soil stack in one ofthe cupboards in there which i can run a pipe from the washmachine /sink into . if this is ok obviously i have to go out the new extension wall to link up with a drain running along the outside , is it ok to go through the wall below the dpc . hope this all makes sense and someone can help me