Connecting bath waste

[David E]

I have a problem that I can sort, but I am wondering if there is a easier way.

I am installing a new bath and I want to plumb the waste under the floorboards - no problem the run is the same way as the joists. When I reach the wall I need to turn 90deg and through two joists which runs each side of an internal wall to the vertical soil pipe on the other side from another bathroom - I remembered to knock half a block out before putting the floor joists in so have a clear path through the wall, but obviously a more difficult path through the joist as it it the last one and there is only 150mm? gap between the previous one and this one so access to drill a 38mm hole through is difficult.

I know water does not flow up hill so please avoid the smart comments!!!!, but the soil pipe from the toilet passes 150mm? above the bath waste where i need to turn 90deg and goes through the same internal wall and obviously runs above the joists not through them. Is there a way of connecting the bath waste to this having made the run under the floor without having the nasty problem of water from the toilet coming up through the bath trap?

 

[chrishutt]

In answer to your second para., you definitely should not be trying to connect bath waste to soil pipe branch. they should join the vertical stack separately.

You should be aware of limits on area of joists can be drilled out for your waste. I think the ends of joists should not be drilled, and holes should not be more than 25% of joist depth.

Any chance of dropping the bath waste into the room below to avoid joists? It could be boxed in....

 

[David E]

It was just a hope that there may have been a way to connect into the horozontal soil pipe properly. Luckily the first joist is the last one in a run and spaced at 150mm rather than 450mm on one side, and on the other side of the wall the joist is supported midway so looking on a Building regs table I can remove plenty. Its just going to be an awkward job going through the joist with a chisel.

unfortunately it cant run through the room below.

David