Shower waste

[duffsparky]

Hi Guys,

I wonder if someone could give me some help? I'm trying to work out if I can get enough waste discharge from my 2 showers into the soil stack.
See drawings below.

• [code:1][/code:1]

Shower waste 1

• duffsparky
• 11 Aug 2009
• 2

Shower waste 2

• duffsparky
• 11 Aug 2009
• 2

All the pipework is to be below the floor and both shower waste pipes need to join together before they pass through floor joists and connect into the soil stack.

The pipe length from each shower is 2190mm + (1200 to 1530mm) and 3620mm + (1200 to 1530mm) exceeds the Building Regs recommendations.

Connecting the pipes as per the first drawing will make life much easier but looking at the Building Regs I don't think I can install them that way.

The second drawing is my understanding of the building regs except the pipe lengths are too long.

Rather then using conventional shower waste traps I wondered about using the Typhoon Vortex or the James (vortex) Waste, both made by Wirquin. These wastes are supposed to be high flow, self cleaning and unblockable. Any of you Guys have any input on these waste?

I'd be grateful if someone could look over my idea's and put me right where I'm wrong.

In particular I'm not sure about the need and or position of the vent pipe and AAV. I wondered if I should have one at each shower end rather than one in the middle?

If the vent or vents are needed I'd prefer to run it/them into the loft through the partition wall shown, to keep them out of sight.

Again if the vent pipe(s) are needed, is fitting AAV(s) the best way to go or should I install pipes between the dry stack in the loft and the top of the new vent pipes(s) installed up through the partition wall>

Thanks in advance,

duffsparky.

 

[TicklyT]

Is your SE happy with the sizes and positions of the holes you propose drilling in the joists?

Normally, the holes should not be within 1/4 span of the supporting walls, the holes should be no more than 1/4 depth of the joists (= 45mm) and all holes should be on the centre line of the joists, leaving no room for any fall on the pipe.
The proximity of the holes to the existing notches in the joists may also be an area of concern unless you can provide the calculations to prove the design integrity.

 

[duffsparky]

TickltT, I don't know what you mean by SE but I assume it refers to Building Control.

I intend bonding the existing overlapping joists together with a structural epoxy resin used for repairing and extending timber joists; my local building control dept has agreed to this as being an acceptable means of reinforcing the joists prior to drilling holes outside those specifications dictated in the Building Regulations, therefore I should be able to get the minimum fall of 93mm (18 x 5.150). If I don't need to reuse the notches I will fill and repair them as per recognised proceedures.

 

[Nige F]

Structural Engineer . Don`t know about these fancy vortex wastes But If you can get access I would use Hep V O waste valves on the horizontal runs from each tray . Diagram 2 looks better with the swept tees. Have a google on"2 pipe Vented soil stack" re your idea of taking vent pipes up into roof and back into main vent . That`s such an old way I`m not sure it`s actually called 2 pipe stack . Not that it`s a bad way at all, just more labour + material . Nice to see someone applying good engineering principles

 

[duffsparky]

Structural engineer - doh! why didn't I think of that

I hope to trim the floor joists adjacent to the waste traps, then put removable panels in the floor the other side of the partition wall, that way access underneath the shower trays shouldn't be a problem, I hope.

The idea of coupling the new vent pipes to the existing stack was just a thought, in case it would be a better option. I had originally intended fitting a single AAAV atop a single vent pipe taken from the point where the 2 shower waste branch pipes meet, as shown on the drawing. However, I've since been told this may not work properly and I'd be better taking a seperate vent pipe from each waste trap position.

I've also been told different things about pipe sizes, so I'm starting to scatch my head a bit and from that I'm getting splinters.

I find it easier to ask a series of listed/bulleted questions especially as I know what I'm trying to ask but often it gets lost in my ramblings, and I apologise for those ramblings.

Should I install:-

• 40mm or 50mm pipe throughout?
  40mm for the 2 branch pipes and 50mm from the branch pipes to the soil stack?
  50mm through out?
  A single centrally located AAAV as shown on the drawing?
  Separate vent pipes taken from each waste trap position with an AAAV atop of each.

If I can get them in, would it be better to install 2 x 40mm pipes through the joists rather than a single 50mm, if 50mm were required of a single pipe?

As the AAAV(s) and waste pipes serve only showers that are located on the same level, what is the minimum height they should be installed - sink overflow or perhaps lower?

Kind regards,

duffsparky