Following a first-floor bathroom remodel done poorly by a plumber in our house a couple of years ago I have stripped everything out and I'm starting over and plan to install our original 'vision' carefully and properly. I found that the 110mm vent stack was terminated just below a hole in the ceiling (with the attic above). It was behind panelling and had an OsmaVent 110 4S304 AAV just loosely placed in the top of the pipe without any form of seal. Fortunately, we never had any discernible sewer smells so the rest of the drainage system appears in good condition (main drain collector is in the back garden so we can hear every flush for us and our near neighbours!). Here's the question:
- Section 1.32 of The Building Regulations 2010 Drainage and Waste Disposal states that "...stack ventilation pipes (the dry part above the highest branch) may be reduced in size in one and two storey houses, but should be not less than 75mm".
- I want to restore a (properly sealed) AAV in the attic space.
- Ideally I need to gain a few extra cms (off the diameter of a 110mm pipe) to properly accommodate the bath and shower instead of boxing the stack off to the side and creating a lot of waste space in the process in the last iteration.
- Does anyone know of a manufacturer who sells 110mm to 75mm adapters or, preferably, one who sells a rectangular soil vent pipe and adapter the same as can easily be found for ventilation & air conditioning systems, albeit for 100mm or 125mm vent pipe?
- Has anyone been able to install a similar work around?
