WC into understairs pantry - queries... anyone here?

[advicewelcom]

Hi, looking to do two projects:



PROJECT (A): Want to bring garage WC to below the stairs pantry
PROJECT (B): Then maybe turn the garage WC area into a shower room

Pic of the PROJECT (A) basic move:

Pic of the garage WC:

Pic of the pantry area:

Garage WC and Pantry on either side of the same wall with the Garage WC being a step down:

Further pics and details here:
Move Garage WC to understairs Pantry and convert Garage WC to a Shower Room - https://photos.app.goo.gl/GtCgH2a9YbByReJy8


First step is PROJECT (A) and its a nightmare tyring to find one person/company to do this at this time. So working out what I can do myself and the plumbing is the main issue so hence posting here. Can post elsewhere if needed:


I think the steps to do PROJECT (A) is:
1 Get the plumbing in for the new WC by extending waste through the wall
2 Plumb in the feeds for the WC and small sink
3 Fix a stud wall for the cistern and pan to sit against
4 Do the pantry floor
5 Plumb and bolt in the WC
6 Plumb and fix in the sink
7 Fix an ventilation fan
8 Make a door into the hallway
9 Stud wall where the current door is

These steps make sense?

Anything I am missing or anything else worth considering?

Welcome feedback, will have questions. Ta!

 

[oz-plumber]

As far as plumbing goes, from your pics.
Looks like an S-Trap pan, so sewer goes into floor. ( No need to extend waste through wall)

As far as Plumbing is concerned.
Get a jackhammer. Jackhammer up floor in pans current location and to a point where new pan is to be relocated.
Continue to Jackhammer up floor to point where sink is to be located.
Install below ground sewer to locations required.
Install water supply to new fixture locations

The rest is cosmetic, so no plumbing input required - bar fitting pan and sink.


*This is assumed the floor is concrete.

 

[advicewelcom]

Thanks for reply.

So jackhammering up the concrete is certainly a solution, but considering the new pantry WC is on the other side of wall with a floor that is 2 bricks higher than the current garage WC floor - I don't see how that is an easy option. Jack hammering up the concrete to the sink location or the shower waste - will mean we have know where they should be upfront and it will not be easy to change that for any reason (and it may need to change as you never know where things need to be until you try and fit them).

How about the below...

(A) This is the new raised wooden floor that will be level with the pantry floor on the other side of the wall. This floor will also be level with the kitchen floor and provide easy access to the new garage shower room from the kitchen. On this raised floor will be the new shower tray - probably on a plinth as the new pantry WC 110mm waste pipe (B) will have to go above that floor and then go through to the pantry new WC (save anyone having to dig up the pantry floor).

(B) This is the soil waste pipe plumbing. Probs consist of a 4" to 110m fitting from the current floor collar - then a 90 degree bend - a waste connection for the garage sink and shower - and then an extension to go through to the new pantry WC.

(C) This is the waste connection to the sink and waste. I am not sure if this should be before the bend or after (as show in pic). I am thinking that it can be after the bend as the 110mm pipe will have to have a plinth above it and then the waste pipe can go under that to the traps in the shower and sink connection. The waste for the shower could be on the furthest side from the pantry wall which would make it easy to access for any maintenance. I understand that the shower tray plumbing pipe needs a fall.


I guess my questions are:

1) Does this design make sense - or any major issues with it? I am thinking maintenance and access for issues in the future as well?

2) If I dug up the pantry floor I could run the new WC waste pipe extension under the new garage floor (A) and thus avoid having to put the shower on raised plinth - but I don't want the hassle of digging up the pantry floor - is this a bad move?

3) If the (C) waste connection is after the bend - are the falls from a shower tray not going to be possible under a shower plinth unless it is a very high plinth (as the shower hole will be other side of the tray for maintenance access).

4) Should I have the (C) waste connection before the bend to ensure enough fall gradient for the piping from the shower tray waste? I could put a small floor trap door access to get to the shower piping if that's a good idea?

5) Will the shower tray and sink connections stop any chance of fouls smells from the new pantry WC piping coming up from the sink or shower waste?

Welcome any replies.

 

[oz-plumber]

Everything you're asking depends on the depth of the existing drain you are intending to connect to.

Once you've determine the depth of the existing graded horizontal drain you can work out what you need to do for the rest.

 

[advicewelcom]

Everything you're asking depends on the depth of the existing drain you are intending to connect to.

Once you've determine the depth of the existing graded horizontal drain you can work out what you need to do for the rest.

Hi - the depth of the clay soil pipe that is running into the garage from underground?

Really? But am connecting form the clay collar upwards and into the pantry - so hows the depth of it under the ground matter?