Connect modern 40mm waste to older pipework

[chilluk]

I need to rework some waste pipe in our downstairs loo. I assumed it was standard 40mm solvent weld waste pipe as the house is less than 20 years old.

I bought some floplast pipes and elbows etc from screwfix. Offering up a connector it is obvious the new pipe is larger than the old. The old pipe has an outer diameter pretty much exactly 40mm so I presume an older sizing system.or perhaps it's an imperial size?

Can I buy a step down adaptor to connect new piping to old? What do I need? Searching seems to offer 40mm to 32mm or 50mm, not what I need.

Thanks in advance.

 

[CBW]

Which bit are you trying to rework? If a basin waste could be 32mm which in solvent weld would be 36mm. Maybe post a photo? Markings on the fittings?

 

[RandomGrinch]

The old pipe has an outer diameter pretty much exactly 40mm so I presume an older sizing system.or perhaps it's an imperial size?

Push fit waste has an OD of 41mm compared to solvent welds 43mm.

Can I buy a step down adaptor to connect new piping to old?

A universal compression coupler should do the job...

FloPlast WC08 Universal Compression Waste Straight Coupler White 40mm x 40mm - Screwfix

 

[chilluk]

The pipework was serving a basin, and then 2 up stands for washing machine and tumble drier. It's kind of a utility as well as downstairs loo.

The basin part is stepped down to 32mm, well at least this pipework version of it!

The rest is all 40mm outside diameter. I am trying to get rid of one of the upstands as we don't have a dryer and the washing machine is quite deep so we want to push it back further, hence the need to chop a chunk out. It is a mix of solvent weld and compression fittings as the u bends etc are compression.

I can't make out any markings on the pipework, only on a retaining clip it says Osma I believe.

I will give the suggested universal compression fitting a go. Thanks for the suggestions.

 

[chilluk]

I bought the Floplast compression coupler from Screwfix - obviously it's a lot tighter on the new pipe than the old. Even with it done up as tightly as possible I can force the old thinner pipe to move albeit it's not loose as such - think it's going to be watertight?!!

 

[Hugh Jaleak]

If you are concerned, how difficult is it going to be to change all the waste pipework?

 

[chilluk]

The issue I have is that the pipe that goes into the floor (already tiled!) is the older diameter so at some point it will have to connect to that.

I have managed to find some markings on one of the old elbows : Osma 5Z160 90 deg ABS - just googled and that linked to a Wavin product on Travis Perkins - is it likely that modern versions of that will still be same dimensions? If so I will chuck away the Floplast bits I bought and try that.