I am probably overthinking this!

I have a basin waste, which is a 40mm pipe with a screw thread on it.

I want the waste to go through a 90 curve then back about 15cms. Then
some sort of trap, and end up connected to a 32mm waste pipe. The waste
pipe is around 25cms lower than the bottom of the basin waste.

I don't have any of this type of pipe in stock. So, I need to go
shopping at Screwfix. I'd prefer just to go once.

What should I put on my shopping list, please? :)

--- SoupGate-Win32 v1.05
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On Wed, 29 Jan 2025 20:09:25 +0000, GB <NOTsomeone@microsoft.invalid> wrote:

I don't have any of this type of pipe in stock. So, I need to go
shopping at Screwfix. I'd prefer just to go once.

What should I put on my shopping list, please? :)

Possibly a "flexible waste pipe". Bend to suit, done.

(I have one in a shed, where I bend it into a trap when it's warm ,and straight to drain all water when it might freeze. Works...)


Thomas Prufer

--- SoupGate-Win32 v1.05
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GB <NOTsomeone@microsoft.invalid> wrote:

I am probably overthinking this!

I have a basin waste, which is a 40mm pipe with a screw thread on it.

I want the waste to go through a 90 curve then back about 15cms. Then
some sort of trap, and end up connected to a 32mm waste pipe. The waste
pipe is around 25cms lower than the bottom of the basin waste.

I don't have any of this type of pipe in stock. So, I need to go
shopping at Screwfix. I'd prefer just to go once.

What should I put on my shopping list, please? :)

I think you will find a bottle trap with a 32mm outlet will fit directly
onto the basin waste and will probably project below the sink not much more than any pipe connections you will need to directly connect a pipe to it.
Using such a bottle trap will mean simply completing the connection in the
same 32mm pipe.

Richard

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 29/01/2025 20:09, GB wrote:

I am probably overthinking this!

I have a basin waste, which is a 40mm pipe with a screw thread on it.

Is this the bit that pokes out the bottom of the basin that is the
directly under the plug hole?

If so, any standard basin trap should screw onto this. A simple U bend
type may be the best option. The connect a pipe to the output of that
and appropriate fittings to get to your final 32 mm pipe.

Check if you need pushfit or solvent weld (if unsure go for compression "universal" fittings - they will seal on either).

I want the waste to go through a 90 curve then back about 15cms. Then
some sort of trap, and end up connected to a 32mm waste pipe. The waste
pipe is around 25cms lower than the bottom of the basin waste.

I don't have any of this type of pipe in stock. So, I need to go
shopping at Screwfix. I'd prefer just to go once.

What should I put on my shopping list, please? :)

Use swept bends rather than sharp elbows, and consider using a swept tee
with a rodding eye in the unused end for one of the bends.

--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk | \=================================================================/

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 30/01/2025 22:43, John Rumm wrote:

On 29/01/2025 20:09, GB wrote:

I am probably overthinking this!

I have a basin waste, which is a 40mm pipe with a screw thread on it.

Is this the bit that pokes out the bottom of the basin that is the
directly under the plug hole?

If so, any standard basin trap should screw onto this. A simple U bend
type may be the best option. The connect a pipe to the output of that
and appropriate fittings to get to your final 32 mm pipe.

Check if you need pushfit or solvent weld (if unsure go for compression "universal" fittings - they will seal on either).

I want the waste to go through a 90 curve then back about 15cms. Then
some sort of trap, and end up connected to a 32mm waste pipe. The
waste pipe is around 25cms lower than the bottom of the basin waste.

I don't have any of this type of pipe in stock. So, I need to go
shopping at Screwfix. I'd prefer just to go once.

What should I put on my shopping list, please? :)

Use swept bends rather than sharp elbows, and consider using a swept tee
with a rodding eye in the unused end for one of the bends.

I should have explained this better in the first place!

I have fitted a new basin to an old piece of bathroom furniture. The
furniture sticks out from the wall and is 9" deep. I need to keep the
pipework within the furniture if possible.

The old trap is 7" tall, but with the new basin that's about an inch too
tall. It sticks out at the bottom of the furniture, and besides looking
odd it stops me closing the access panel.

So, I think you are right. I need an extra shallow trap with a a 40mm
inlet and preferably a 32mm outlet. Then I can just finish the
connection in 32mm pipe, and I don't need a converter.

Is it just me, or is the Screwfix website very bad at specifying both
the inlet and the outlet connections on their traps?

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

GB <NOTsomeone@microsoft.invalid> wrote:

On 30/01/2025 22:43, John Rumm wrote:

On 29/01/2025 20:09, GB wrote:

I am probably overthinking this!

I have a basin waste, which is a 40mm pipe with a screw thread on it.

Is this the bit that pokes out the bottom of the basin that is the
directly under the plug hole?

If so, any standard basin trap should screw onto this. A simple U bend
type may be the best option. The connect a pipe to the output of that
and appropriate fittings to get to your final 32 mm pipe.

Check if you need pushfit or solvent weld (if unsure go for compression
"universal" fittings - they will seal on either).

I want the waste to go through a 90 curve then back about 15cms. Then
some sort of trap, and end up connected to a 32mm waste pipe. The
waste pipe is around 25cms lower than the bottom of the basin waste.

I don't have any of this type of pipe in stock. So, I need to go
shopping at Screwfix. I'd prefer just to go once.

What should I put on my shopping list, please? :)

Use swept bends rather than sharp elbows, and consider using a swept tee
with a rodding eye in the unused end for one of the bends.

I should have explained this better in the first place!

I have fitted a new basin to an old piece of bathroom furniture. The furniture sticks out from the wall and is 9" deep. I need to keep the pipework within the furniture if possible.

The old trap is 7" tall, but with the new basin that's about an inch too tall. It sticks out at the bottom of the furniture, and besides looking
odd it stops me closing the access panel.

So, I think you are right. I need an extra shallow trap with a a 40mm
inlet and preferably a 32mm outlet. Then I can just finish the
connection in 32mm pipe, and I don't need a converter.

Is it just me, or is the Screwfix website very bad at specifying both
the inlet and the outlet connections on their traps?

Something like this is probably the answer. It does not have a water trap
but uses a valve system to prevent sewer smells coming up the outlet.

https://www.screwfix.com/p/mcalpine-wash-hand-basin-space-saver-with-self-closing-waste-valve-white-32mm-x-32mm/863hp

In my previous post I suggested a trap with a 32mm outlet would probably
fit as the normal bathroom basin outlet is 1 1/4” BSP thread so how
accurate is your 40mm measurement? 32mm pipe fits inside the outlet which
is obviously wider than that.

Richard

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Tricky Dicky <tricky.dicky@sky.com> wrote:

GB <NOTsomeone@microsoft.invalid> wrote:

On 30/01/2025 22:43, John Rumm wrote:

On 29/01/2025 20:09, GB wrote:

I am probably overthinking this!

I have a basin waste, which is a 40mm pipe with a screw thread on it.

Is this the bit that pokes out the bottom of the basin that is the
directly under the plug hole?

If so, any standard basin trap should screw onto this. A simple U bend
type may be the best option. The connect a pipe to the output of that
and appropriate fittings to get to your final 32 mm pipe.

Check if you need pushfit or solvent weld (if unsure go for compression
"universal" fittings - they will seal on either).

I want the waste to go through a 90 curve then back about 15cms. Then
some sort of trap, and end up connected to a 32mm waste pipe. The
waste pipe is around 25cms lower than the bottom of the basin waste.

I don't have any of this type of pipe in stock. So, I need to go
shopping at Screwfix. I'd prefer just to go once.

What should I put on my shopping list, please? :)

Use swept bends rather than sharp elbows, and consider using a swept tee >>> with a rodding eye in the unused end for one of the bends.

I should have explained this better in the first place!

I have fitted a new basin to an old piece of bathroom furniture. The
furniture sticks out from the wall and is 9" deep. I need to keep the
pipework within the furniture if possible.

The old trap is 7" tall, but with the new basin that's about an inch too
tall. It sticks out at the bottom of the furniture, and besides looking
odd it stops me closing the access panel.

So, I think you are right. I need an extra shallow trap with a a 40mm
inlet and preferably a 32mm outlet. Then I can just finish the
connection in 32mm pipe, and I don't need a converter.

Is it just me, or is the Screwfix website very bad at specifying both
the inlet and the outlet connections on their traps?

Something like this is probably the answer. It does not have a water trap
but uses a valve system to prevent sewer smells coming up the outlet.

https://www.screwfix.com/p/mcalpine-wash-hand-basin-space-saver-with-self-closing-waste-valve-white-32mm-x-32mm/863hp

In my previous post I suggested a trap with a 32mm outlet would probably
fit as the normal bathroom basin outlet is 1 1/4” BSP thread so how accurate is your 40mm measurement? 32mm pipe fits inside the outlet which
is obviously wider than that.

Richard

PS

Just looked up BSP threads and 1 1/4” has an outside diameter of 41.9mm.
Push a 32mm length of pipe into your outlet and if it fits without too much waggle then a 32mm fitting will do.

Richard

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 31/01/2025 15:55, Tricky Dicky wrote:

Tricky Dicky <tricky.dicky@sky.com> wrote:

GB <NOTsomeone@microsoft.invalid> wrote:

On 30/01/2025 22:43, John Rumm wrote:

On 29/01/2025 20:09, GB wrote:

I am probably overthinking this!

I have a basin waste, which is a 40mm pipe with a screw thread on it. >>>>

Is this the bit that pokes out the bottom of the basin that is the
directly under the plug hole?

If so, any standard basin trap should screw onto this. A simple U bend >>>> type may be the best option. The connect a pipe to the output of that
and appropriate fittings to get to your final 32 mm pipe.

Check if you need pushfit or solvent weld (if unsure go for compression >>>> "universal" fittings - they will seal on either).

I want the waste to go through a 90 curve then back about 15cms. Then >>>>> some sort of trap, and end up connected to a 32mm waste pipe. The
waste pipe is around 25cms lower than the bottom of the basin waste. >>>>>
I don't have any of this type of pipe in stock. So, I need to go
shopping at Screwfix. I'd prefer just to go once.

What should I put on my shopping list, please? :)

Use swept bends rather than sharp elbows, and consider using a swept tee >>>> with a rodding eye in the unused end for one of the bends.

I should have explained this better in the first place!

I have fitted a new basin to an old piece of bathroom furniture. The
furniture sticks out from the wall and is 9" deep. I need to keep the
pipework within the furniture if possible.

The old trap is 7" tall, but with the new basin that's about an inch too >>> tall. It sticks out at the bottom of the furniture, and besides looking
odd it stops me closing the access panel.

So, I think you are right. I need an extra shallow trap with a a 40mm
inlet and preferably a 32mm outlet. Then I can just finish the
connection in 32mm pipe, and I don't need a converter.

Is it just me, or is the Screwfix website very bad at specifying both
the inlet and the outlet connections on their traps?

Something like this is probably the answer. It does not have a water trap
but uses a valve system to prevent sewer smells coming up the outlet.

https://www.screwfix.com/p/mcalpine-wash-hand-basin-space-saver-with-self-closing-waste-valve-white-32mm-x-32mm/863hp

In my previous post I suggested a trap with a 32mm outlet would probably
fit as the normal bathroom basin outlet is 1 1/4” BSP thread so how
accurate is your 40mm measurement? 32mm pipe fits inside the outlet which
is obviously wider than that.

Richard

PS

Just looked up BSP threads and 1 1/4” has an outside diameter of 41.9mm. Push a 32mm length of pipe into your outlet and if it fits without too much waggle then a 32mm fitting will do.

Richard

I'll check, but I think that must be the answer. I know that basin
wastes are normally "32mm", but it's really confusing that I can't find anywhere that says the OD is around 40mm. OFC, that makes perfect sense
if the 32mm pipe is going to fit inside.

I just need a 32mm trap, and I'll have a take-back-athon of the 40mm
stuff. :)

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

GB <NOTsomeone@microsoft.invalid> wrote:

I'll check, but I think that must be the answer. I know that basin
wastes are normally "32mm", but it's really confusing that I can't find anywhere that says the OD is around 40mm. OFC, that makes perfect sense
if the 32mm pipe is going to fit inside.

I just need a 32mm trap, and I'll have a take-back-athon of the 40mm
stuff. :)

Yes this is the problem of not going fully metric. You still have a lot of legacy imperial stuff still being produced in this case waste outlets but
also tap tails which are also in BSP. I know the argument is that so much exists and you need to Be able to connect new to old but if you keep
producing the imperial stuff you will never phase it out.

BTW have you considered the low profile trap I linked to it looks not much
more than what you would have using standard waste fittings to link to
either a bottle or P trap at the back of your cupboard?

As for finding out the OD just Google BSP threads and plenty of charts come
up, of course you would need to know that the item has an imperial thread.
In British plumbing generally anything pipework that attaches to a
component by a thread is almost always imperial BSP (British Standard
Pipe).

Richard

--- SoupGate-Win32 v1.05
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On 01/02/2025 13:44, GB wrote:

I'll check, but I think that must be the answer. I know that basin
wastes are normally "32mm", but it's really confusing that I can't find anywhere that says the OD is around 40mm. OFC, that makes perfect sense
if the 32mm pipe is going to fit inside.

I just need a 32mm trap, and I'll have a take-back-athon of the 40mm
stuff. :)

Also be careful that solvent weld pipe has a slightly different OD to
push fit or compression fit pipe. I once made this mistake and had
already cut the pipe before realising that the other fittings didn't seal :(

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 01/02/2025 15:16, alan_m wrote:

On 01/02/2025 13:44, GB wrote:

I'll check, but I think that must be the answer. I know that basin
wastes are normally "32mm", but it's really confusing that I can't
find anywhere that says the OD is around 40mm. OFC, that makes perfect
sense if the 32mm pipe is going to fit inside.

I just need a 32mm trap, and I'll have a take-back-athon of the 40mm
stuff. :)

Also be careful that solvent weld pipe has a slightly different OD to
push fit or compression fit pipe.  I once made this mistake and had
already cut the pipe before realising that the other fittings didn't
seal :(

Just to add to the joy, I decided to buy a tool to cut the 32mm pipe, as
it was a confined space and I needed to get it right first time. The
cutter is described as a 35mm pipe cutter.

Why, for heavens sake?

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

GB <NOTsomeone@microsoft.invalid> wrote:

On 01/02/2025 15:16, alan_m wrote:

On 01/02/2025 13:44, GB wrote:

I'll check, but I think that must be the answer. I know that basin
wastes are normally "32mm", but it's really confusing that I can't
find anywhere that says the OD is around 40mm. OFC, that makes perfect
sense if the 32mm pipe is going to fit inside.

I just need a 32mm trap, and I'll have a take-back-athon of the 40mm
stuff. :)

Also be careful that solvent weld pipe has a slightly different OD to
push fit or compression fit pipe.  I once made this mistake and had
already cut the pipe before realising that the other fittings didn't
seal :(

Just to add to the joy, I decided to buy a tool to cut the 32mm pipe, as
it was a confined space and I needed to get it right first time. The
cutter is described as a 35mm pipe cutter.

Why, for heavens sake?

Do not know what type you had in mind but something like this should do
what you want and work up fairly tight up to a wall. There are cheaper but again it depends on how much room you have to manipulate them.

https://www.screwfix.com/p/faithfull-3-42mm-manual-plastic-pipe-cutter/587gc

Richard

--- SoupGate-Win32 v1.05
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On 04/02/2025 17:01, Tricky Dicky wrote:

GB <NOTsomeone@microsoft.invalid> wrote:

On 01/02/2025 15:16, alan_m wrote:

On 01/02/2025 13:44, GB wrote:

I'll check, but I think that must be the answer. I know that basin
wastes are normally "32mm", but it's really confusing that I can't
find anywhere that says the OD is around 40mm. OFC, that makes perfect >>>> sense if the 32mm pipe is going to fit inside.

I just need a 32mm trap, and I'll have a take-back-athon of the 40mm
stuff. :)

Also be careful that solvent weld pipe has a slightly different OD to
push fit or compression fit pipe.  I once made this mistake and had
already cut the pipe before realising that the other fittings didn't
seal :(

Just to add to the joy, I decided to buy a tool to cut the 32mm pipe, as
it was a confined space and I needed to get it right first time. The
cutter is described as a 35mm pipe cutter.

Why, for heavens sake?

Do not know what type you had in mind but something like this should do
what you want and work up fairly tight up to a wall. There are cheaper but again it depends on how much room you have to manipulate them.

https://www.screwfix.com/p/faithfull-3-42mm-manual-plastic-pipe-cutter/587gc

Richard

I splashed out on one of these: https://www.screwfix.com/p/monument-tools-35mm-manual-plastic-pipe-cutter/407jj

--- SoupGate-Win32 v1.05
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