Dear fellow DIYers

I am hoping to move a bathroom from the front of my house to the
middle, but I don’t really want to have to put a new soil stack in
unless necessary. My question is: How far is too far in terms of a
horizontal run for a soil pipe? I am proposing to have an (almost)
horizontal run for about 3 metres. I’m not too bothered about how it
will look as it will run along the ceiling of an integral garage. I
know that they have to have a certain fall distance per metre, I’m
just not sure what it is. I have searched the group but it seems like
older posts have gone? I would appreciate any advice on the matter and
no, I am not going to install a macerator - they are the devils work!

The house is semi-detached and luckily the side where the new bathroom
is to go is the farthest outer wall, so it would not be the end of the
world if I had to dig up outside etc.

Thanks in advance.

Both the maximum length of a branch pipe and the minimum gradient are
specified, *along with numerous other details of sanitation design*,
in the building regs part H.

Min gradient is 18mm per metre

Max length is 6m for a single WC.

TheTaffia wrote:
Dear fellow DIYers

I am hoping to move a bathroom from the front of my house to the
middle, but I don’t really want to have to put a new soil stack in
unless necessary. My question is: How far is too far in terms of a
horizontal run for a soil pipe? I am proposing to have an (almost)
horizontal run for about 3 metres. I’m not too bothered about how it
will look as it will run along the ceiling of an integral garage. I
know that they have to have a certain fall distance per metre, I’m
just not sure what it is. I have searched the group but it seems like
older posts have gone? I would appreciate any advice on the matter and
no, I am not going to install a macerator - they are the devils work!

The house is semi-detached and luckily the side where the new bathroom
is to go is the farthest outer wall, so it would not be the end of the
world if I had to dig up outside etc.

Thanks in advance.
I suggest that you confirm this but 110mm soil pipe fittings installed
properly give a 2.5 degree fall so I would assume this is not a bad
start. I have used this angle on what must be almost 3m from a WC to the
stack. It works tolerably well (since 1985!!) but the flush is poor
sometimes.

I think the technical term used for this sort of consideration is
referred to needing to achieve "self cleaning velocity". Basically if it
is too steep the water runs past and leaves the turds behind and too
shallow and the water builds up behind static turds.
Whatever you end up with makes sure you have suitable access for rodding.

Bob

On 27 Aug, 13:04, Bob Minchin wrote:
TheTaffia wrote:
Dear fellow DIYers

I am hoping to move a bathroom from the front of my house to the
middle, but I don’t really want to have to put a new soil stack in
unless necessary. My question is: How far is too far in terms of a
horizontal run for a soil pipe? I am proposing to have an (almost)
horizontal run for about 3 metres. *I’m not too bothered about how it
will look as it will run along the ceiling of an integral garage. I
know that they have to have a certain fall distance per metre, I’m
just not sure what it is. I have searched the group but it seems like
older posts have gone? I would appreciate any advice on the matter and
no, I am not going to install a macerator - they are the devils work!

The house is semi-detached and luckily the side where the new bathroom
is to go is the farthest outer wall, so it would not be the end of the
world if I had to dig up outside etc.

Thanks in advance.

I suggest that you confirm this but 110mm soil pipe fittings installed
properly give a 2.5 degree fall so I would assume this is not a bad
start. I have used this angle on what must be almost 3m from a WC to the
stack. It works tolerably well (since 1985!!) but the flush is poor
sometimes.

I think the technical term used for this sort of consideration is
referred to needing to achieve "self cleaning velocity". Basically if it
is too steep the water runs past and leaves the turds behind and too
shallow and the water builds up behind static turds.
Whatever you end up with makes sure you have suitable access for rodding.

Bob- Hide quoted text -

- Show quoted text -

The fall angle needs to be a compromise to achieve self cleaning
velocity for floaters and sinkers.

On Thu, 27 Aug 2009 23:30:03 -0700, gunsmith wrote:
I think the technical term used for this sort of consideration is
referred to needing to achieve "self cleaning velocity". Basically if it
is too steep the water runs past and leaves the turds behind and too
shallow and the water builds up behind static turds.
Whatever you end up with makes sure you have suitable access for rodding.

The fall angle needs to be a compromise to achieve self cleaning
velocity for floaters and sinkers.

The true DIYer would have flexible elbows in the system and a
motorised winch - press a button in the bathroom to set the appropriate
angle for whatever's about to be flushed...