Need some help urgently 🙁
Just having an extension done and the ensuite has thrown me.
Basically I wanted a low walk in shower tray. Unfortunately the joists run the wrong way so I’m struggling to get the waste out to the soil pipe. I don’t really want to raise the shower so thought about raising the whole floor. Effectively there’ll be a 5″ step from bedroom to ensuite bathroom… Does this sound like a bad idea ?

Yes, it does sound like a bad idea and will add cost to the job as well as put any future buyers off your home.

Do you have space under the joists and just run the waste pipe lower. May need to cut a new hole in the outside wall for it to exit lower and adjust the soil pipe or hopper.

No, can’t go below as it’ll be in the middle of the room downstairs.
Can’t go outside and back in according to builder… Mmmm, yes, must admit it seemed a good solution at the time but now not so sure ??

Why do you want low walk? Can you make a little step up?

Can you not drill through the joists?
I’m sure ours are drilled for plumbing…

DrP

either drill the joists like DrP suggests (hole saw for example) or compromise with the walk in shower? yes a step in shower is less cool, but a step into the room isnt great and is more costly.. you’ll go into the room v frequently, into the shower less so (if you think about it…) i know the shower will be used alot too but a bathroom is more than just a shower..

Can’t drill the joists as it conflicts building regs when they’re a certain distance from the support. Sticking with raising it, as pointed out above, you’d go in the room less than having a shower lol. And being p’d up and falling into the bathroom at 4am aint my idea of fun 🙂

Can’t drill the joists as it conflicts building regs when they’re a certain distance from the support.

I didn’t know that. Surely there must be limits on size of whole etc ?

I was going to suggest drilling through the joists.

I certainly know that when our cellar was converted, the joists were drilled for electrics. The building inspector didn’t say anything about that.

Edit: Is it worth ringing building regs and asking them to review what you would be allowed? From quick googling is how big the whole is as a % of the beam, where it is on the beam, and the amount of stress the beam is under.

Could you not do the joist and then put a bracket around the joist to reinforce it?

I don’t see the point raising the whole floor. All you’re doing is moving the same size step elsewhere at great expense, and I can see stubbed toes when going for a nocturnal pee..!
Just have a step into the shower, where it’s expected to be found

My parents had this and just raised the shower cubicle, looks and works fine – not sure why you’d think raising the whole floor would be a better idea?

Edit: actually that’s not quite true – they ended up having that area of the bathroom itself raised so the jacuzzi they have cuts into the raised area so it’s almost like a sunken bath effect. Still think it would look fine just stepping up to the cubicle though

if builder has said no drilling, then we might assume no drilling.

He will have worked out that the hole would not be central to the joist, no more than 25% of the joist height and within 25-40% of the ends of the joist.

are you sure you cant do a run parallel with the joists for a while until within the 25-40% range and then turning across?

+1 on not raising the floor, will look terrible.

I presume the layout cant be changed to put shower on external wall?

Otherwise, could room below tolerate a slightly lower ceiling?

Saying that, it is a lot of effort and cost to not step up into a shower once a day.

Depending on the size and layout of the bathroom you could build a raised plinth which extends beyond the shower enclosure. That can look good.