What do I need to connect the trap to the waste?
What do I need to connect a sink trap to the waste pipe? I've googled all sorts and haven't reached a conclusion.. I hope you can help! It is a standard 1 1/4" bottle trap. I can provide pictures of it helps!
Advice from 4 local tradespeople
Yes — for a standard 1 1/4" bottle trap, the outlet is normally 32 mm, so you usually connect it to the waste pipe with a 32 mm trap outlet/compression connection. McAlpine's 1 1/4" bottle traps are listed as 32 mm. Their trap outlets are commonly multifit compression outlets that suit plastic waste pipe.
In most normal UK basin setups, what you need is:
the 1 1/4" bottle trap
a 32 mm waste pipe
and either:
the trap's own compression outlet if it already clamps straight onto the pipe, or
a 32 mm wall flange / compression-to-pipe adaptor if you are connecting into a pipe stub coming out of the wall. McAlpine describes these outlets as compression/multifit connections for plastic, copper, or lead waste pipe.
So the simple answer is:
If your bottle trap already has a compression outlet nut and washer on the horizontal outlet, you normally just slide that onto a 32 mm waste pipe and tighten it. You do not usually need anything exotic.
What changes the answer is the end you are connecting to:
If there is a plain 32 mm plastic pipe coming from the wall, your trap will often connect directly onto it with the trap's compression fitting.
If there is no pipe yet, you need a 32 mm waste pipe to run from the trap to the wall/drain connection.
If you have a chrome trap connected to a plastic pipe, there are also specific adaptors for chrome-to-plastic connections.
A practical rule:
Basin + 1 1/4" trap = usually 32 mm waste
Sink + 1 1/2" trap = usually 40 mm waste. McAlpine's product listings for 1 1/4" bottle traps consistently identify them as 32 mm.
If you send a photo of:
the trap,
the pipe coming out of the wall/floor,
and the gap between them,
I can tell you exactly which fitting you need.
Are you referring to a wash hand basin or a kitchen sink?
Kitchen sinks require 40mm traps commonly p-traps (spidget).
Wash Basins 32mm only S- traps , P-traps, bottle traps, inline depending on requirements.
Commonly solvent weld or compression type fittings are used.
Depending on what is there depends on what you’ll need to connect.
If you’re simply replacing what type was used then it should be a straight swap unless its a different type.
You will need 32mm pipe and fitting such as 45 degree bend 90 degree bend and 32mm couplings.
Waste pipe with a compression fitting
