replanning a bathroom

[pmx_super]

Hi,

I'm looking to install a new bathroom in my flat and would like to change the layout, however I'm unclear as to how feasible this is. All of the existing pipework emerges from solid (i.e. not stud) walls.

My questions are:

- Is there a difference between the feeds to a bath vs. sink? Could the two be interchanged and hooked up to the pipework for the other? It seems that baths get a better flow rate than sinks when filling though maybe this is just because the taps are that little bit lower..? Are the pipes bigger or something?

- Is it possible to relocate a toilet at all when the waste pipe is built into a solid wall? Is it possible to extend the run from the back of the toilet in order to hook it up to the exiting waste outlet (then box it in)? I'm looking to move the toilet about 50 cm to the right.

All input most gratefully received.

James

 

[GJS]

Baths are usually fed from 22mm pipes and have larger bore taps. Basins are usually fed from 15mm to smaller bore taps. You will usually find that just a 22mm hot and a 22mm cold enters the bathroom and the basin feeds are then tapped off of those, as well as a 15mm cold supply for the toilet cistern.

Yes, you can relocate the toilet, I have just done this, about 700mm along the wall. You can fit additional soil pipe extending to the new toilet position, or use a collection of pan connectors and extenders to reach to the original position of the waste. Beware, though, that you must have a fall from the toilet to the soil pipe. So the further you move the toilet the higher up it will need to go. You need a fall of 1:20 (though many sources quote 1:40) so, everything else being equal, the toilet will have to be raised by 25mm to get 1:20, 12.5mm to get 1:40, if you are moving it by 50cm.

The only way to raise a toilet and get a good finished result, that I have found, is to raise the whole floor, using plywood sheet screwed down to it before fittting the final floor covering. Obviously, there comes a point where you need a step ladder to get into the room!

 

[pmx_super]

Great, thanks for the info GJS. Since I'm virtually swapping the bath and sink around it looks like I'll just have to extend the existing pipework in boxed-in runs. On closer inspection, I'm rather concerned that the outlets feeding the sink emerge from the wall higher than the top of the bath.. not sure what to do about that.

On the toilet thing, I think I can raise it by 15 mm without it being too obvious since the pile in the carpet of the adjacent room is at least that deep. I can't screw plywood into the floor though - I've got concrete floors! I expect I can figure something out...some kind of underlay beneath the tiles maybe.

 

[GJS]

The pipes to the sink may need to be moved but more likely you can just stop end them, fill over, then do new runs to the new sink and bath.

If your tiling the floor, and the toilet is sitting on the floor at the moment, you may get 15mm just from the tiles and adhesive.

 

[Goldspoon]

I can't screw plywood into the floor though - I've got concrete floors!

Long brass screws and Raw Plugs and a good drill...

 

[pmx_super]

The pipes to the sink may need to be moved but more likely you can just stop end them, fill over, then do new runs to the new sink and bath.

To do a new run to the sink could I just take 15mm spurs off the existing 22mm bath feeds?

If your tiling the floor, and the toilet is sitting on the floor at the moment, you may get 15mm just from the tiles and adhesive.

Yeah, the bathroom is currently carpeted (in brown - nice!) so the toilet is sitting on the concrete floor. I'll try to choose the chunkiest tiles available.

 

[Goldspoon]

To do a new run to the sink could I just take 15mm spurs off the existing 22mm bath feeds?

Yes you can

 

[pmx_super]

Yes you can

Thanks.

I have also detected a flimsy back wall to a built in cupboard that adjoins the bathroom, so I'm hoping if I take that away there should be access to the pipes before they emerge from the bathroom wall...