Please help. We are currently looking at a project to convert our existing bathroom into a bedroom, with a new bathroom being created on the opposite side of the property. We have significant issues with installing a new soil stack and considering running bath/toilet/ sink waste pipe on the outside wall of the property down to the existing soil stack as this will enable us to achieve the required fall for a soil waste pipe with a total length of approx 7m. Looking at the building regs part H it appears a max length of 6m exists for branch connections, but the document also makes reference to exceeding this distance if the pipe itself is ventilated? I am assuming this is in addition to normal soil stack ventilation? Does anyone have any experience with a similar situation if so any advice would be gratefully received.