Laundry room sink / appliance plumbing wobble…

[Omnibuswoman]

Today I decided to start to learn plumbing - cue a very frustrating day with some comical moments. 
 

I’m at the point of changing the temporary appliance waste upstand for a sink P trap with double appliance nozzles where the laundry room sink will go, and have hit some difficulties:

 

Stoopidly I didn’t realise that each brand of plumbing parts are slightly different in size, so the McAlpxxx trap won’t connect to the Flo-plxxx pipework. I’m also uncertain about how to arrange the connection of the P trap to the incoming waste pipe. Photo attached of existing waste arrangement. (The end of the horizontal pipe sits where the sink waste needs to go.)
 

The Flo-plxxx double nozzle P trap also gets appalling reviews and isn’t sold at SF.
 

Is there an alternative brand that will connect to the Flo-plxxx 40mm waste pipe?

 

Any suggestions how to configure the sink waste to meet the horizontal pipe?
 

thanks!

 

[dpmiller]

you'll need to help us a wee bit here- pushfit and solvent are different sizes, but some compression fittings can span both, not really a "brand" thing. What exact sink trap do you have there?

[Gone West]

11 hours ago, Omnibuswoman said:

Stoopidly I didn’t realise that each brand of plumbing parts are slightly different in size

As @dpmiller says pushfit and solvent are different diameters. This table may help.

 

Pipe sizes and dimensions chart.pdf

[Russell griffiths]

Why is the waste so high up the wall?

what is on the other side of that wall, could/ should the waste be lower

[Omnibuswoman]

Thanks, yes when I first did the waste run I realised that the plumber (who had put in the soil stack and a nominal piece of waste pipe) had used solvent weld pipe, so the push fit fittings I had bought had to go back to SF to be changed for solvent weld. 

When I bought the washing machine waste upstand pipe fitting, which is a compression fitting, I was surprised to find that it would fit onto the solvent weld pipe. 
 

The sink waste with the double appliance nozzles is McAlpine. This won’t connect to the existing solvent weld flo-plast pipe. 

 

[Omnibuswoman]

7 minutes ago, Russell griffiths said:

Why is the waste so high up the wall?

what is on the other side of that wall, could/ should the waste be lower

 
This is the other side of the wall, under the half-landing. The plumber set the first 400mm of pipe coming out from the soil stack, and I took it across from there, and then through the wall. Where the waste pipe joins the washing machine upstand the top of the pipe is around 500mm off the floor. 

(This was my first ever go at plumbing, so please don’t judge too harshly!! 😳)

[Nickfromwales]

43 minutes ago, Omnibuswoman said:

 
This is the other side of the wall, under the half-landing. The plumber set the first 400mm of pipe coming out from the soil stack, and I took it across from there, and then through the wall. Where the waste pipe joins the washing machine upstand the top of the pipe is around 500mm off the floor. 

(This was my first ever go at plumbing, so please don’t judge too harshly!! 😳)

Ok! After the first bend, you are then on quite a steep incline. This is putting your washing machine (appliance) upstand quite high off the floor.

 

Yes, you can guess what I’m going to say next…..

 

The amount of incline in the room itself is good, just you’ve used up too much ‘fall’ in the service space. 
 

You could abandon the connection to the stack and ‘boss’ in lower down, but that’s prob worst case scenario.

 

This needs a tweak first, to lower the pipe as it enters the utility space, to lower that upstand.

 

Good effort though, and good on you for getting stuck in / hands dirty

 

I’d lose the blocks that you’ve used as stand offs, and simply use 2x 45° bends to see the pipe out just before it goes through the wall. 
 

Is there any reason you’ve not run the pipe on the plain OSB wall and then just punched through exactly where the pipe meets a trap?
 

 

Would save cutting the back of units / navigating around that horizontal waste pipe run in the utility. 

[Omnibuswoman]

Thanks @Nickfromwales  

 

I should have explained more…. the upstand is only a temporary thing that allowed us to use appliances before making the laundry room up into a proper utility space.  
 

The plan is to have a four-unit sized (roughly 2450mm) run along the laundry room wall with dishwasher (later to be replaced with tumble drier), washing machine, sink unit, and fridge. I shoved the upstand in last year just to allow us to have use of the dishwasher and washing machine. My plan now is to take that out, and fit a proper sink P trap with double nozzles for the two appliances in the final location, as HWMBO is fed up of swapping over the two drainage tubes every time we use the appliances. (I’m also doing the incoming water connections to allow both appliances to be connected at the same time instead of swapping them over, which is what we have been doing.)
 

The upstand location is 1550mm from the R hand wall, which is essentially where the middle of the laundry sink will sit. The fail in my plan was to buy a McAlpine sink trap, which I now find won’t connect with the existing Flo-Plast pipework, and that is what I was looking to BH’s hive mind for. 
 

Having said all of that, I appreciate your plumbing wisdom, and wonder if you still think the waste pipe is too high if it is only connecting to a sink P trap and not having the upstand in place?

 

Thanks!! 
 

 

[Nickfromwales]

24 minutes ago, Omnibuswoman said:

Thanks @Nickfromwales  

 

I should have explained more…. the upstand is only a temporary thing that allowed us to use appliances before making the laundry room up into a proper utility space.  
 

The plan is to have a four-unit sized (roughly 2450mm) run along the laundry room wall with dishwasher (later to be replaced with tumble drier), washing machine, sink unit, and fridge. I shoved the upstand in last year just to allow us to have use of the dishwasher and washing machine. My plan now is to take that out, and fit a proper sink P trap with double nozzles for the two appliances in the final location, as HWMBO is fed up of swapping over the two drainage tubes every time we use the appliances. (I’m also doing the incoming water connections to allow both appliances to be connected at the same time instead of swapping them over, which is what we have been doing.)
 

The upstand location is 1550mm from the R hand wall, which is essentially where the middle of the laundry sink will sit. The fail in my plan was to buy a McAlpine sink trap, which I now find won’t connect with the existing Flo-Plast pipework, and that is what I was looking to BH’s hive mind for. 
 

Having said all of that, I appreciate your plumbing wisdom, and wonder if you still think the waste pipe is too high if it is only connecting to a sink P trap and not having the upstand in place?

 

Thanks!! 
 

 

Ah!

 

Then no, you’ll be fine.

 

Most appliance manufacturers will give a max height for the discharge hose to be at, when going into an upstand, so that is now deleted from the situation and a (combination) trap will be fine.

 

I’d still move the pipework to the other side of the wall if possible.

[Omnibuswoman]

Thanks. I will have a look at how far along the hallway wall I can bring it before it comes through. I could maybe disguise it by building out the lower part of that wall as a little shelf feature. Watch this space!!

[marshian]

7 hours ago, Omnibuswoman said:

Thanks. I will have a look at how far along the hallway wall I can bring it before it comes through. I could maybe disguise it by building out the lower part of that wall as a little shelf feature. Watch this space!!

 

Just a comment.......

 

I like solvent weld pipe far more than I like gasket fittings but when using solvent weld I always consider how I'm going to be able to either remove the section or rod / hose out the pipework in the case of blockages - washing machine powder can build up in pipe work if "someone" over doses the machine on a regular basis (I think this is amplified by cooler temperature washes).

 

In fact the think about future access / maintenance applies to a lot of plumbing in homes.

 

 

[Omnibuswoman]

On 01/11/2025 at 10:53, Nickfromwales said:

 

I’d still move the pipework to the other side of the wall if possible.

 

@Nickfromwales I have now removed the pipe and am planning to turn the corner and bring it along the hallway wall instead of the laundry side. You mentioned using two 45° bends, rather than a 90° - is this to turn the corner more gently and reduce the risk of blockages? Any other advice? 
Thanks!

Edited 14 hours ago by Omnibuswoman

[Nickfromwales]

8 minutes ago, Omnibuswoman said:

 

@Nickfromwales I have now removed the pipe and am planning to turn the corner and bring it along the hallway wall instead of the laundry side. You mentioned using two 45° bends, rather than a 90° - is this to turn the corner more gently and reduce the risk of blockages? Any other advice? 
Thanks!

Only suggested, if you lost the blocks of wood.

 

A 90° bend in the corner is 👍. 
 

@marshian makes a good point, so make the final 90° bend going into the utility a T instead, and put a cleaning eye in the redundant open end so you can ‘self clean’. 

[Omnibuswoman]

Thank you! 

[marshian]

24 minutes ago, Nickfromwales said:

@marshian makes a good point, so make the final 90° bend going into the utility a T instead, and put a cleaning eye in the redundant open end so you can ‘self clean’. 

 

Thank you @Nickfromwales - That's certainly what I would do to add a bit of easy maintenance access when using solvent weld

 

I also only tend to use compression/gasket waste fittings on vertical drops less chance of a leak on a vertical pipe

 

(obviously you can't do much about P traps and bottle traps as they are all gasket type)

 

[Nickfromwales]

7 minutes ago, marshian said:

I also only tend to use compression/gasket waste fittings on vertical drops less chance of a leak on a vertical pipe

Horse manure. 
 

Solvent weld all day long.   

[marshian]

1 minute ago, Nickfromwales said:

Horse manure. 
 

Solvent weld all day long.   

 

If I can avoid them I will and I'll use solvent weld as much as possible but if I have no choice then that's what I try to do when I do use one.

 

Downside of an 80's house where several people have had their fingers on the plumbing over the years 

[Nickfromwales]

4 minutes ago, marshian said:

 

If I can avoid them I will and I'll use solvent weld as much as possible but if I have no choice then that's what I try to do when I do use one.

 

Downside of an 80's house where several people have had their fingers on the plumbing over the years 

Compression stuff is pretty bombproof, so I can accept the compromise which you are proposing lol.