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

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.

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.

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.

oz-plumber said:

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.

Click to expand...

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?

This isn't plumbing questions but wondering if anyone has a view on WC pantry flooring...

I was told it was quarry tiled floor and should not put plywood on top for lino as it would sweat. It does seem a bit damp as possibility there is no ventilation in the pantry currently.

Is it desirable to expose this traditional tiled floor? Can it be improved somehow, polished or cleaned easily?

Or if the floor is not that level, is it better to put some self level compound on it and finish it off with some flooring?

advicewelcom said:

This isn't plumbing questions but wondering if anyone has a view on WC pantry flooring...

I was told it was quarry tiled floor and should not put plywood on top for lino as it would sweat. It does seem a bit damp as possibility there is no ventilation in the pantry currently.

Is it desirable to expose this traditional tiled floor? Can it be improved somehow, polished or cleaned easily?

Or if the floor is not that level, is it better to put some self level compound on it and finish it off with some flooring?

Click to expand...

If your property is Victorian or Edwardian, there is probably no damp proofing beneath the quarry tiles, they may be laid on the earth, or cement or sand directly on the earth. If you cover them over with anything you will be inviting damp to creep up the walls. If you can leave the floor as it is (I would!) and keep the room ventilated, you shouldn't have any damp problems.
There are ways to clean the quarry tiles - cement removing acid and abrasion to clean them. Worth looking on internet forums etc. Broken ones can be carefully replaced - EBay has period tiles on sale for example, and there are specialists for spares. You can treat/polish them when clean, but you need permeable products to allow moisture through.
I've had a number of period houses from the 1500's to Edwardian, and learnt that the less you interfere with the original construction, the better. Modern materials generally just cause side effects that get worse over time than the original issue you had 🤪

Thanks for the reply. Its a semi - so I suspect its a 1940s build. I am sure these tiles are under the entrance hallway carpet as well (near the front door). I guess I would need to chip away and take one up to be sure what its lying on? And cement it back down?

Found this, which seems to provide some guidance along with your reply.
Ultimate Quarry Tile Cleaning Guide - Professional Tile and Stone Restoration - https://tilelife.uk/ultimate-quarry-tile-cleaning-guide/



The plumber guy was going to come and slap self levelling compound over them as floor is a bit uneven. Your saying this is not a great idea, try clean them up and add a ventilator fan in the space - as the best approach? Plywood ontop with some lino is not really and option - or can be for short term? I guess tiling on top with some Victoria design tiles is not a long term option either?

advicewelcom said:

Thanks for the reply. Its a semi - so I suspect its a 1940s build. I am sure these tiles are under the entrance hallway carpet as well (near the front door). I guess I would need to chip away and take one up to be sure what its lying on? And cement it back down?

Found this, which seems to provide some guidance along with your reply.
Ultimate Quarry Tile Cleaning Guide - Professional Tile and Stone Restoration - https://tilelife.uk/ultimate-quarry-tile-cleaning-guide/

The plumber guy was going to come and slap self levelling compound over them as floor is a bit uneven. Your saying this is not a great idea, try clean them up and add a ventilator fan in the space - as the best approach? Plywood ontop with some lino is not really and option - or can be for short term? I guess tiling on top with some Victoria design tiles is not a long term option either?

Click to expand...

If it's 1940's there might be a DPM, in which case you could do what you like over the top. You really need a damp meter (and learn how to interpret it!) to check for damp, or if you know it's damp then I would suggest perhaps not putting anything over the top.
A latex self levelling screed is not permeable, so that's like putting waterproofing over your floor, which, If there is damp, will eventually give you damp up the walls because it can't get out through the floor! Then the plaster blows and mold etc and you end up having to inject the wall with damp proofing, which either does nothing or it pushes the damp to pop up elsewhere!

But as I say if there is a damp proof membrane under the floor and at the bottom of the wall, you should be fine. You could excavate a little to find out how it's built.
You might get away with marine ply for some years, but you could get mould and eventually plaster blowing as a result.
If you tile over the top with permeable tiles (not porcelain or glazed ceramic, maybe limestone or clay pavers ok?) and the same for the adhesive and grout, you might be OK