Please help - Routing a waste pipe in difficult situation!

[angelheart0604]

Hi, I have a bath sink and toilet on the back wall in my bathroom. The sink waste links in with the bath one at the back of the bath, goes outside along the back wall then into the main waste pipe in the corner of a semi detached house. I am looking at putting a single storey extension on the back the house with a lovely pitched roof. Unfortunately that then means that this waste pipe coming from the bathroom would be inside my extension and be visible and it would not really good enough to just box it in.

I realise there is the option of going under the floorboards and out in the corner directly into the waste pipe but my house is steel framed and therefore this makes this option difficult. On thing I thought of perhaps is using some sort of flexible 38-40mm waste pipe and putting this in the cavity of the back wall and coming out in the corner and going directly into the existing connection of the main waste pipe.

BUT I don't really know if it is possible to buy something like this in a length cos I am just a girl! Any ideas or advice would be greatly appreciated! Many thanks

 

[Hugh Jaleak]

Putting it in the cavity I think is a non starter! You need to look at either rerouting existing internally, is it possible to box it in at floor level inside the bathroom?

Alternatively could it be hidden in the loftspace of your proposed extension? I assume you intend to engage a builder to construct the extension, they would be better placed to advise. Without being on site it is difficult to visualise the existing and proposed arrangements. If you could provide a picture of the current setup, that may help.

 

[angelheart0604]

Yes I may well post a pic. Can't put it in the loft space of the extension as the roof is going to be pitched and exposed with dorma windows therefore all pipes will be visible. Builders are not always great with offering advice on complicated plumbing jobs I find. There is also not really enough space to box it internally and also you couldn't get the drop from the bath waste as waste as far too low as it is.

Um................

 

[Fridgemonkey]

1. You are not "just" a girl anymore than I'm just a "monkey" (who can write). Stop it!
2. In a waste pipe, the fall required is 10 mm for every 1 metre or steeper if possible. Someone check me on this because I don't have the regs to hand. So you only need 30 mm drop for a 3 metre run for example.
3. I agree that inside the cavity is a bad idea because there is always that 1/1 million chance you need access and any leaks into a cavity would be very bad!
4. I think your only option is to box in the pipes including the 110 mm toilet waste either on the bathroom side at skirting board level or in the exposed roof space. This box can either be camouflaged in matching colour or a feature made of this. Ideally one surface should be easily removable with a few discrete screws just in case service is necessary.
5. Finally, do you mean "Dorma windows"? These are something you would have in a first floor extension. perhaps you mean "skylights"?

 

[powell30]

You could pump the waste into the loft then into a suitable stack. Costs would be dearer than just rerouting tho. Without seeing your property it is only a suggestion. Call in a plumber and see what they suggest/offer....

 

[angelheart0604]

Yes skylights, that is what I meant! There is always the possibility of chasing out part of the exterior wall so it pretrudes less and therefore after plasterboard has been put on etc, it won't show. Access would still be a problem though....

 

[Hugh Jaleak]

You are looking at a 40mm dia pipe to take combined bath and sink wastes, provided it has correct fall and bends are kept to a minimum then it could be concealed behind the plasterboard, if rodding eyes are fitted where necessary then possibly use small removeable panels to cover them.

Alternatively, is it possible reroute the wastes to drop vertically in a corner of the extension? Whilst this could be boxed into the corner, it is however likely to need underground pipework installing which incurs additional costs...