Thank you all. Just for reference, there's no hopper - it's an internal cast iron soil stack.
If a plastic strap boss is not recommended, does anyone know of a metal one? Don't fancy threading the hole as has been done before.
Thanks, Ralph
Hi. Just moving into 'new' house with internal CI soil stack and doing bathroom (and kitchen below). All waste connections OK except bathroom sink and bath connections which run up hill to threaded connections (soil stack has 1 1/2" holes, threaded and screwed in short iron pipes (then plastic)...