Waste pipe from free standing bath

[alanfrank]

Hi, Could somebody advise please. I am in the process of moving my main bathroom to a bigger room at the rear of the house and consequently there is no existing plumbing. I have bought a free standing bath which seems to sit flush on the floor. What puzzles me is where the waste pipe goes. Do I need to construct a raised platform for the bath to sit on or do I need to run the waste pipe under the floor boards? If it is the latter I would need to drill through two or three floor joists to reach the outside wall. Is this wise or will it weaken the structure?
Thats a lot of questions I know but I am really uncertain? I would appreciate any views or similar experiences. Thanks

Alan

 

[seco services]

depnds how deep the joists are to how large you holes can be.
then you still need to have a downward run on your waste, but the holes in any joist must be in the centre. so not always the ideal way to go.
notching is out of the question.

can you fit the bath on a raised platform ?

 

[RHS]

I would say you need planning permission for this so after you have been through the process your building inspector MAY advise you on what to do.

 

[dextrous]

Relocating a bathroom is notifiable as RHS says.

What will happen if you run the waste pipes following the line of the joists - how far before you reach an ouside wall? Or, what's below the bathroom - you may have to drop the wastepipe into this and box it in.

 

[Fluffster]

I have installed a few of these trendy baths which tend to weigh about 60 kilos too!

We usually lay marine ply and cut a large hole in this between the joists where we use a long 40mm bore flexible connector to attach from the trap to the main waste pipe.
This enables easier installation and access to the trap without the risk of rigid pipework being dislodged.

Pete

ps only use the full bore Mc alpine flexis as the cheaper ones are usually a smaller bore.

 

[alanfrank]

depnds how deep the joists are to how large you holes can be.
then you still need to have a downward run on your waste, but the holes in any joist must be in the centre. so not always the ideal way to go.
notching is out of the question.

can you fit the bath on a raised platform ?

Thanks for your advice. The joists are about 7" deep and looking at it again I would probably have to drill through only two as the bath was going to be located adjacent to the gable end meaning the waste would be about 18" to 2' from the exterior wall. When you mention the raised platform, are you questioning whether it is possible to fit a bath on a platform because its a difficult job or contrary to building regs?
Regards
Alan[/quote]

 

[alanfrank]

I would say you need planning permission for this so after you have been through the process your building inspector MAY advise you on what to do.

Thanks. I must admit I hadn't realised that was the case. It shows that it is right what they say about " a little knowledge being a dangerous thing. "
I think the guy (below) with the Elvis quote may be correct! I've now got to break the news to the wife that it won't all be sorted by the end of the month!!!

 

[seco services]

you can fit on a platform if you like. will it look right in your bathroom or do you want it on a platform ?

if you don't you can use a flexi as said. you fit the trap and flexi fit bath in place then you can join your flexi to the waste pipe etc.

 

[alanfrank]

I have installed a few of these trendy baths which tend to weigh about 60 kilos too!

We usually lay marine ply and cut a large hole in this between the joists where we use a long 40mm bore flexible connector to attach from the trap to the main waste pipe.
This enables easier installation and access to the trap without the risk of rigid pipework being dislodged.

Pete

ps only use the full bore Mc alpine flexis as the cheaper ones are usually a smaller bore.

Pete thanks for that. Do you mean replace the floorboards with marine ply or put ply over the boards to reinforce them. My original plan ( on third party advice ) was to lay 1/4" ply over the existing boards which would reinforce the flooring for tiling. Do you think this would be sufficient?
Cheers
Alan

 

[alanfrank]

you can fit on a platform if you like. will it look right in your bathroom or do you want it on a platform ?

if you don't you can use a flexi as said. you fit the trap and flexi fit bath in place then you can join your flexi to the waste pipe etc.

I take your point about the platform. You are right it wouldn't be ideal but I think I am running out of options. The point about the flexipipe is still puzzling me because, flexi or not, I still have to either go through the joists or drop them through the ceiling into the room below, or have I misunderstood.

Alan

 

[alanfrank]

Relocating a bathroom is notifiable as RHS says.

What will happen if you run the waste pipes following the line of the joists - how far before you reach an ouside wall? Or, what's below the bathroom - you may have to drop the wastepipe into this and box it in.

Thanks for your help. Following the line of the joists doesn't really make any difference as after a few feet the joists start to run in the opposite direction so I would be faced with the same dilemma. I think you are right dropping the pipe into the room below may be the only real option. Cheers. Alan

 

[Fluffster]

To tile over floorboards you should ensure all the boards are secure then lay a sheet of ply and secure every 100mm in squares with galvanised screws.
Then use a flexible tile adhesive and grout.
This will give you a trouble free floor for many years.

Do not be tempted with the wonder product which states you can tile directly onto floorboards with.

ps in reference to the trap depth you can use a shallow trap of about 80mm.
Pete

 

[alanfrank]

To tile over floorboards you should ensure all the boards are secure then lay a sheet of ply and secure every 100mm in squares with galvanised screws.
Then use a flexible tile adhesive and grout.
This will give you a trouble free floor for many years.

Do not be tempted with the wonder product which states you can tile directly onto floorboards with.

ps in reference to the trap depth you can use a shallow trap of about 80mm.
Pete

Thanks again. Do you agree that I will have to drop the waste pipe into the room below or in your experience is there another way round it?

Cheers Alan

 

[Fluffster]

You have 7 inch joists so any sized trap will fit in that void.

Pete

 

[alanfrank]

You have 7 inch joists so any sized trap will fit in that void.

Pete

Pete, sorry to be a pain mate. The void isn't the problem, the real issue is that the joists run perpendicular to the direction of the waste pipe. My concern was whether it would be safe to bore through two joists to run the waste through the gable wall to the soil stack or if that would weaken the flooring structure too much. I thought my options were to a)drill through the joists, b) build a stepped timber platform to raise the bath off floor level or c) as has been suggested , drop the pipe through the ceiling of the room below and box it in.You sound a lot more experienced than me in fitting bathrooms so what would your advice be?