Plumbing a sewer pipe in cavity wall

Curious Geroge · 12-10-2013 8:11pm #1

In the middle of a new build and we're putting the sewer pipe in the cavity to keep these out of site. We've 2 of these, taking the ensuite bathrooms. The main sewer is going straight up from the raft with a T connector at 2nd level for the toilet and then I continue the pipe up to vent it at roof level. I left the connector at 190mm above finished floor for the toilet but I'm not sure how I will plumb the drain from the shower and sink water into the same sewer pipe. Should I have another connector for these also ?

oikster · 12-10-2013 8:49pm

190mm seems a tad high to me as a tad low is better in my eyes.Yes you will need separate connections for showers,baths etc. Have you considered access for cleaning and noise from pipework when in use?

Curious Geroge · 12-10-2013 8:54pm

oikster wrote: »

190mm seems a tad high to me as a tad low is better in my eyes.Yes you will need separate connections for showers,baths etc. Have you considered access for cleaning and noise from pipework when in use?

Re noise, yes. The pipework goes vertical from ground bathroom to ensuite above. On the second, its in the hallway so chances of ensuite in use while hallway is occupied was worth the visual of hiding the pipework.

On the separate connections, is there another junction that takes 2 drain pipes (sink and shower) I should be adding before adding the T section for the toliet ?

oikster · 12-10-2013 9:00pm

Yes it is called a waste manifold and is very handy in a situation like yours. You will have to keep it about 300mm below your toilet tee and drop your waste pipes into it. These manifolds come with varying numbers of connections 5/7 etc.
Here you go http://www.google.co.uk/imgres?imgurl=http://www.floplast.co.uk/uploads/images/pages/News_Soil%2520Manifold.jpg&imgrefurl=http://www.floplast.co.uk/news/soil-manifold&h=1239&w=1239&sz=415&tbnid=MauphhcDVczb4M:&tbnh=90&tbnw=90&zoom=1&usg=__YFZRRhmxmLnqEgXxPpRBGTe058Q=&docid=s913Slf8ld0HtM&sa=X&ei=36pZUvjmF8nM0QWc9oHwBA&ved=0CFsQ9QEwBw

Curious Geroge · 12-10-2013 9:08pm

oikster wrote: »

Yes it is called a waste manifold and is very handy in a situation like yours. You will have to keep it about 300mm below your toilet tee and drop your waste pipes into it. These manifolds come with varying numbers of connections 5/7 etc.
Here you go http://www.google.co.uk/imgres?imgurl=http://www.floplast.co.uk/uploads/images/pages/News_Soil%2520Manifold.jpg&imgrefurl=http://www.floplast.co.uk/news/soil-manifold&h=1239&w=1239&sz=415&tbnid=MauphhcDVczb4M:&tbnh=90&tbnw=90&zoom=1&usg=__YFZRRhmxmLnqEgXxPpRBGTe058Q=&docid=s913Slf8ld0HtM&sa=X&ei=36pZUvjmF8nM0QWc9oHwBA&ved=0CFsQ9QEwBw

Thats perfect. thanks for the quick response, should get that sorted now before it goes any further.

skippy5 · 12-10-2013 9:10pm

What happens when the seals start to leak, wont happen for a while, but will eventually.

Curious Geroge · 12-10-2013 9:15pm

skippy5 wrote: »

What happens when the seals start to leak, wont happen for a while, but will eventually.

Thats always a worry but same applies to plumbed joints under the floor boards so I'll probably create a sealed access point and check regularly. Thats all I can think off.

skippy5 · 12-10-2013 9:24pm

Thats probally a good idea, you never know the day you may need access

corkgsxr · 12-10-2013 9:46pm

skippy5 wrote: »

What happens when the seals start to leak, wont happen for a while, but will eventually.

I wouldn't be too worried about them. Your pipe is going down into them. Even loose it would be hard to leak out of that.

Worst is the 40mm wavin strap on bosses with the rubber bush. Im always replacing them on dropping soils

Dtp1979 · 12-10-2013 11:15pm

What about damp coming from the external wall? Using the sewer pipe to bridge

Curious Geroge · 12-10-2013 11:28pm

Dtp1979 wrote: »

What about damp coming from the external wall? Using the sewer pipe to bridge

The main sewer is off the outer and inner walls and I've some insulation lining it so when its pumped later it should get surrounded fully. Will be adding airtight tape where ever possible to seal all opening so special attention here.

Plumbing a sewer pipe in cavity wall

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