3" soil stack

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Does anyone know if it is alowable to connect a wc, basin and shower via a macerator in either 32 or 40mm into a 3" soil stack/vent as the connection to the 4" part is no longer accessible.The 3" stack is conected directly into and above the 4" and is a single stack system with no secondary venterlation, the building currently has only one wc and is 2 storys high soon to be 3 with this loft convertion.
 
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Yes you can, buy why you would want to fit an macerator is anybody' guess
 
thanks doitall, the reason for the poo masher is that i don't think you can run a 3" wc waste can you? its about a 4.5 m run and the fall i can get is about 15mm/m because of the existing celing joists and new ones.
 
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Re-design it so the loo is nearer the pipe :rolleyes: or if you have a skillin run the pipe behind that.
 
even with a redesign it will still be a 3" soil stack to conect to and as i said i don't think you can run from the wc in 3" can you???? hence the macerator
 
even with a redesign it will still be a 3" soil stack to conect to and as i said i don't think you can run from the wc in 3" can you???? hence the macerator

Have seen it done before, if you were to run as far as possible in 4" and convert to the 3" in the vertical plain, provided the stack is vented, I would expect it to work.
 
Hi,
I wouldn't advise you to run a 4" pipe into a 3" soil stack, You are asking for trouble. I have many years ago taken out a WC that was piped up to a 3" stack in London but the outlet itself was 3".
I have a feeling that most American WC's have a 3" connection. You may be able to get hold of one of these.
Is it possible to take out the 3" stack and replace it with a 4" one? I know it's a lot of work but once it's done you shouldn't ever have any problems with it.
 
Hi,
I wouldn't advise you to run a 4" pipe into a 3" soil stack, You are asking for trouble. I have many years ago taken out a WC that was piped up to a 3" stack in London but the outlet itself was 3".
I have a feeling that most American WC's have a 3" connection. You may be able to get hold of one of these.
Is it possible to take out the 3" stack and replace it with a 4" one? I know it's a lot of work but once it's done you shouldn't ever have any problems with it.

Ian, if you download Document H, you will see its perfectly acceptable to run a single wc into an 3" soil.
 
Hi,
It may be possible and acceptable with doc H but i personally wouldn't advise it as it can lead to problems.
I was merely lending my experience.
 
Hi,
It may be possible and acceptable with doc H but i personally wouldn't advise it as it can lead to problems.
I was merely lending my experience.

Provided he can get the correct falls it would not be a problem.

I appreciate your comment, and anything out of the ordinary never looks right..

Doc H wouldn't advice it, if it was likely to be troublesome.
 
I appreciate what you are saying and it does state that it's ok in Doc H it's just something i would never do in someones house as i can guarantee that i will get a call back.
 
hi guys, now now lets not argue, having just trawled trough doc H it apears that you can connect one wc to 3" if the trap is also 3" however the property already has one wc on it already and i think the stack was then reduced from 4" to 3" as is allowed as per doc h (page 7 1.28) so conneting it in 3" apears to be out of the question. connecting from 4" to 3"would therefore not be allowed and would contrvene the rules in doc H as the trap and branch need to be the same size. So my question remains.Also ianplumber the work involved to find the 4" stack is unbelievable, i think a macerator would be the best solution if it can be connected.
 
hi guys, now now lets not argue, having just trawled trough doc H it apears that you can connect one wc to 3" if the trap is also 3" however the property already has one wc on it already and i think the stack was then reduced from 4" to 3" as is allowed as per doc h (page 7 1.28) so conneting it in 3" apears to be out of the question. connecting from 4" to 3"would therefore not be allowed and would contrvene the rules in doc H as the trap and branch need to be the same size. So my question remains.Also ianplumber the work involved to find the 4" stack is unbelievable, i think a macerator would be the best solution if it can be connected.

Not so, the 3" reduces from the 4" branch, leaving you free to connect an wc on the 3".

AN Macerator is never a good solution, let alone a best one.

Your building inspector will be involved, ask for his opinion.
 
according to doc h the branch pipe must be a minimum of equal to the trap size of the wc which are 4" so how can you connect this to 3" ?
 

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