Waste pipes within service void or not?

[jayc89]

I currently have a 25mm service void, just enough to run 15mm HEP pipe through, I also need a way of running 40mm waste pipe from one end of a room to another.

I could stud the wall out further, creating a 50mm service void, or just run them on top of the PB, behind the utility room units. 

 

Within a service void would be cleaner, but access to any leaks would be a PITA, as would any relocation of services in the future.

 

Where, possible should I run the waste pipes on top of the PB, behind the units etc, and only effectively box them into a service void where they would otherwise be on display? (Such as in the downstairs W/C between the basin and soil pipe)

[crispy_wafer]

I'd use the space behind the units to be fair, as long as they are 'hidden' from day to day view.

[Carrerahill]

16 minutes ago, jayc89 said:

I currently have a 25mm service void, just enough to run 15mm HEP pipe through, I also need a way of running 40mm waste pipe from one end of a room to another.

I could stud the wall out further, creating a 50mm service void, or just run them on top of the PB, behind the utility room units. 

 

Within a service void would be cleaner, but access to any leaks would be a PITA, as would any relocation of services in the future.

 

Where, possible should I run the waste pipes on top of the PB, behind the units etc, and only effectively box them into a service void where they would otherwise be on display? (Such as in the downstairs W/C between the basin and soil pipe)

Think I would keep it behind the units, it just makes life a bit easier in the future or if there are any leaks etc.

 

Can you go under the floor? Solid slab? 

[jayc89]

45 minutes ago, Carrerahill said:

Think I would keep it behind the units, it just makes life a bit easier in the future or if there are any leaks etc.

 

Can you go under the floor? Solid slab? 

 

Solid slab is already down. In hindsight, I'd have ran all the waste pipes prior to that, including a hidden soil pipe. 

[jayc89]

So here's my plan of attack;

• 2x rooms; utility and W/C
• 32mm from basin waste
• 40mm from utility washing machine and sink
• 110mm from W/C
• SVP is directly behind the W/C location, so a straight run out the wall with a 92.5 degree elbow + branch should work fine there
• 2x boss straps on the 110mm on the internal side of the wall, one with a 32mm adapter and the other with a 40mm adapter, for the other basin/utility waste to connect to
• Utility waste to be hidden behind units
• Basin waste to be boxed in. 

Seems logical to me, does it make sense to everyone else? Is there anything I've missed?

 

 

[jayc89]

On 13/03/2023 at 11:12, jayc89 said:

So here's my plan of attack;

• 2x rooms; utility and W/C
• 32mm from basin waste
• 40mm from utility washing machine and sink
• 110mm from W/C
• SVP is directly behind the W/C location, so a straight run out the wall with a 92.5 degree elbow + branch should work fine there
• 2x boss straps on the 110mm on the internal side of the wall, one with a 32mm adapter and the other with a 40mm adapter, for the other basin/utility waste to connect to
• Utility waste to be hidden behind units
• Basin waste to be boxed in. 

Seems logical to me, does it make sense to everyone else? Is there anything I've missed?

 

 

 

WDYT, @Nickfromwales? Behind the W/C feels like it could get pretty congested without building it out a fair way? (It'll be a wall hung W/C unit, so I'll need to frame it out anyway)

[Nickfromwales]

3 minutes ago, jayc89 said:

 

WDYT, @Nickfromwales? Behind the W/C feels like it could get pretty congested without building it out a fair way? (It'll be a wall hung W/C unit, so I'll need to frame it out anyway)

Run the basin waste in 40mm until it rises vertically at the basin. That's longer than I'd ever run with 32mm tbh. I always take 40mm as close to the basins as is practicable. Pennies of cost for much better performance / longevity. 32mm starts to 'furr' up sooner than you'd think. As there's a long horizontal run you'll have a natural air break, so pointless fitting and anti-vacuum trap on the basin.

Other than that, happy days. Identical to what I've done on my clients build, just the W/M is a water softener and MVHR waste.

[jayc89]

On 15/03/2023 at 08:26, Nickfromwales said:

Run the basin waste in 40mm until it rises vertically at the basin. That's longer than I'd ever run with 32mm tbh. I always take 40mm as close to the basins as is practicable. Pennies of cost for much better performance / longevity. 32mm starts to 'furr' up sooner than you'd think. As there's a long horizontal run you'll have a natural air break, so pointless fitting and anti-vacuum trap on the basin.

Other than that, happy days. Identical to what I've done on my clients build, just the W/M is a water softener and MVHR waste.

 

I have all the 40mm run now and ready to be PB'd, I've used solvent weld pipe as I didn't want to risk leaking push-fit joints when it's covered with PB. Where it terminates (protruding through the PB for the W/C basin and surface mounted for the Utility basin) do I need to convert from solvent weld to push fit before connecting to the traps, or will the compression fittings on the traps support solvent weld pipe too? (32mm bottle trap for the W/C basin, I have a 40/32 reducer for this and 40mm appliance trap for the Utility basin)

Edited April 17, 2023 by jayc89

[Nickfromwales]

Defo do not convert! 
Traps will go onto 32mm solvent weld pipe like a tramp on a kebab. 👌. 

[jayc89]

Think I might have balls'd up on my levels

 

 

I need to run a length of 40mm from behind the W/C frame, through the stud wall across to where the water mains comes up (insulated pipe on the right hand side of the pic). It's bang on the bottom of the single socket.

 

I can drop the tee behind the w/c 2cm max, what's the minimum fall I can get away with for a Utility sink/washing machine waste?

[ProDave]

If it's just the socket that is the issue, move the socket.

[jayc89]

20 minutes ago, ProDave said:

If it's just the socket that is the issue, move the socket.

 

My OCD's getting the better of me as there's another single socket out of shot to the right at the same height as the one in question, so I'd be tempted to move that one as well.

Even if I can get the pipe in below the sockets current location, it's going to make plugging anything in a PITA.

[ProDave]

2 minutes ago, jayc89 said:

Even if I can get the pipe in below the sockets current location, it's going to make plugging anything in a PITA.

I thought the pipe was going IN the wall.

[jayc89]

2 minutes ago, ProDave said:

I thought the pipe was going IN the wall.

It'll be in the wall on the left, behind the W/C frame, surface mounted on the right, as that will be behind utility units (washing machine, sink etc).

[ProDave]

4 minutes ago, jayc89 said:

It'll be in the wall on the left, behind the W/C frame, surface mounted on the right, as that will be behind utility units (washing machine, sink etc).

So sockets are for WM etc so will not be on view.  Stand down the OCD and put the sockets wherever fits once the pipe is in.

[jayc89]

9 hours ago, ProDave said:

So sockets are for WM etc so will not be on view.  Stand down the OCD and put the sockets wherever fits once the pipe is in.

 

What's the best way to patch the old hole? Screw a couple of strips of PB behind the wallboard, glue and screw a new piece of PB to that followed by FibaTape?

[ProDave]

A wooden batten slotted behind and screwed either side then a square of plasterboard screwed or glued to the batten.  Joint filler to make good the gap.  the square cut for the new socket location should be just the right size to fill the old hole.