Stone Shower Tray on Concrete Floor

Discussion in 'Plumbers' Talk' started by PDPS, Jul 31, 2006.

  1. PDPS

    PDPS New Member

    This is probably one of those "suck it and see" or "how long's a piece of string" questions.

    I have to remove a bath and install a stone shower tray, in its place, on a concrete floor. I'd like to keep it as low as possible.

    What happens about the waste and waste pipe?

    I'll use a shower trap and once it's in, it's in. Not happy about difficult access but I'll just have to live with it.

    I need to take the waste pipe through an external wall where it'll discharge into a gully (the one the bath currently discharges into). I don't think I can use the hole the existing bath waste pipe goes through as it'll be too high for the shower tray. If I make a channel in the screed am I likely to be creating problems for myself where the new waste pipe penetrates the external wall? I don't want to risk introducing damp problems.
  2. r2d2

    r2d2 New Member

    What happens about the waste and waste pipe?

    They are buried underneath. Thay must be fitted carefully to ensure no leaks. Be sure to de-burr the pipe edges and leave them nice and smooth so nothing will catch. In your case you could leave access for rodding where the pipe exits the wall.

    If I make a channel in the screed am I likely to be creating problems for myself where the new waste pipe penetrates the external wall? I don't want to risk introducing damp problems.

    If the dwelling is up to current building regs then the screed will be above the damp proof layer so should be no problems. Their should also be 50mm insulation below the screed to play with also.
  3. r2d2

    r2d2 New Member

    Check your levels carefully. The outside surface may be to high for what you are suggesting in which case you will have more problems.
  4. PDPS

    PDPS New Member

    What happens about the waste and waste pipe?

    They are buried underneath. Thay must be fitted
    carefully to ensure no leaks. Be sure to de-burr
    r the pipe edges and leave them nice and smooth so
    nothing will catch. In your case you could leave
    e access for rodding where the pipe exits the
    wall.

    No problem there. All my pipework is always deburred. Good point about rodding access. Probably easier to organise than any other installation I've done.

    If I make a channel in the screed am I likely to
    be creating problems for myself where the new waste
    pipe penetrates the external wall? I don't want to
    risk introducing damp problems.


    If the dwelling is up to current building regs
    then the screed will be above the damp proof layer
    so should be no problems. Their should also be 50mm
    m insulation below the screed to play with also.

    That's what I needed to know. The floor is unlikely to be to current standards as it is around 50 years old. Having said that the building has suffered from damp problems recently (it has fresh plaster around the bottom metre of all walls) so may have been brought up to a reasonable standard.

    There will be a cupboard between the shower and the external wall so I'll probably fit a removable panel rather than fill the channel.

    So - really just a 'suck it and see' job. No customer to embarrass myself in front of as it's my own flat!

    Thank-you!
  5. BTC South

    BTC South New Member

    With regard to laying the tray on the concrete floor, you will still need to lay it on a bed of mortar, due to the fact most shower trays are never perfectly flat on their underside(nor the floor totally level).

    Worked on one job where a tray was simply plonked on the floor with no bedding mix, a 'large' person used the shower and the tray cracked where it was not fully supported ...... Expensive mistake!

    As to laying the waste, you can use a shallow trap, but if you dig down in to the floor, make sure you do not breech the DPC ...... do so and your stuffed.

    Most jobs I see now, where the bathroom has a concrete floor on ground level, they get turned in to wet rooms, with a floor drain.

    As your floor was laid around 50 years ago, it's probably only of a very minimum depth (last I worked on built in 1954 was just on an inch thick and had no DPC under it!) so it might be an idea to dig a small test hole and to see what you are dealing with (better now than later).
  6. PDPS

    PDPS New Member

    With regard to laying the tray on the concrete floor,
    you will still need to lay it on a bed of mortar, due
    to the fact most shower trays are never perfectly
    flat on their underside(nor the floor totally
    level).

    No problem there. I wouldn't expect anything to be flat, level or vertical in this place!

    Worked on one job where a tray was simply plonked on
    the floor with no bedding mix, a 'large' person used
    the shower and the tray cracked where it was not
    fully supported ...... Expensive mistake!

    I guess the owner won't be using that installer again.

    As to laying the waste, you can use a shallow trap,
    but if you dig down in to the floor, make sure you do
    not breech the DPC ...... do so and your stuffed.

    I'll be using a shower trap as I'm a very hairy person (and I moult) so it'll need frequent cleaning. :)

    Most jobs I see now, where the bathroom has a
    concrete floor on ground level, they get turned in to
    wet rooms, with a floor drain.

    I'd like to do that just to gain the experience but, I think, the price would be too high.

    As your floor was laid around 50 years ago, it's
    probably only of a very minimum depth (last I worked
    on built in 1954 was just on an inch thick and had no
    DPC under it!) so it might be an idea to dig a small
    test hole and to see what you are dealing with
    (better now than later).

    Time to take the side off the bath and have a look underneath, I think. At least I can start investigating without doing any visible damage.
  7. mj

    mj Guest

    Why not use a Mira flight tray with a leg pack & plinth kit.
    Very sturdy tray, available in most sizes. Not much higher that a stone resin tray & alot less hastle with the waste pipe.
  8. bathroom boy

    bathroom boy New Member

    Hi Pipe, the last job I did when I was at Dolphin was a shower tray in a flat in Manchester, it was a special needs job, the waste was pumped using 15m/m plastic tube and the waste trap was like an electrical conduit juntion box, small channel cut into solid floor for tube and trap, could have been no more than 30m/m deep.
    The pumps are I believe expensive and they are irritating noisy, made by a company called Plexicare.
  9. PDPS

    PDPS New Member

    Why not use a Mira flight tray with a leg pack &
    plinth kit.
    Very sturdy tray, available in most sizes. Not much
    higher that a stone resin tray & alot less hastle
    with the waste pipe.

    A quick look at the retail prices tells me it's certainly worth taking a look at whatever trade prices I can get for one.

    I do want to keep it as low as possible but it looks as though it should be a lot easier to adjust than trying to fight with a pile of mortar. :)

    Thanks!
  10. PDPS

    PDPS New Member

    Hi Pipe, the last job I did when I was at Dolphin was
    a shower tray in a flat in Manchester, it was a
    special needs job, the waste was pumped using 15m/m
    plastic tube and the waste trap was like an
    electrical conduit juntion box, small channel cut
    into solid floor for tube and trap, could have been
    no more than 30m/m deep.
    The pumps are I believe expensive and they are
    irritating noisy, made by a company called Plexicare.

    No need for fancy wastes and pumps. There's a gully just outside the bathroom that the bath currently discharges into. That'll do nicely.

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