What's the best way to deal with this mess?

Discussion in 'Plumbers' Talk' started by markh1, Oct 12, 2017.

  1. markh1

    markh1 New Member

    I started removing tiles in my ensuite, recently moved in and at some stage the shower had leaked as the kitchen ceiling is damaged. On removing the tiles it removed chunks of plasterboard.

    As you can see from the pictures the room was never tanked and builders never used aquaboard. House is 16yrs old. As a result the plasterboard was water damaged and the damp penetrated the walls and left black mould, on the one wall they put two layers of plasterboard and the mild has grown between them. As you can see they've even skimped on building the cavity walls as they've used cardboard grid which has very small wood beams, not only that but very few wood beams, the wall with the shower on is in better condition but it's still just a cardboard wall and the pipes have not been fixed to any button as that wall has no wood beams in it so any new shower would literally be fixed to the walls by cavity screws.

    I'm putting in a new shower tray, and a dual head shower and want to ensure its watertight and will last some time. My question is how is it best to deal with this? Do I just cover over the damage with some aquaboard or standard board and tank it, or do I rip out all the plasterboard add some more wood beams and cross beams, I would need to peel the cardboard grid from the inside backing and install the smaller 3-3.5cm wood beams and then insulate with some 30mm rock wool board. If I install normal wood beams I'm going to lose a couple of inches of room space which means a smaller shower tray.

    Any ideas how best to deal with this? Thanks

    Attached Files:

  2. Dave does Gas

    Dave does Gas Well-Known Member

    Had a similar situation with a landlord client of mine a couple of years ago, we decided that the best option was a full strip out including some of the stud work and flooring and rebuilt from scratch.
    It may seem extreme but he now has peace of mind that the unit has been installed to his standards and is still good to this day.
  3. WillyEckerslike

    WillyEckerslike Well-Known Member

    It's paramount board - a ready made double skinned partition system popular a while back. Your point about reducing the space for the shower (if you were to build a full size partition) is valid and will create its own problems. In your case I think I would be inclined to remove any eggbox that's damaged/mouldy, clean up and cut out neat lines in the sound plasterboard and replace with Aquaboard or similar adding additional battens as required, glued in place. Allow the area to dry out first and treat with a mould killer/fungicide by the way.
    CGN likes this.
  4. CGN

    CGN Well-Known Member

    Had a similar issue on a renter refurb a couple of years back.
    As Willy mentioned, its paramount board.
    I'd personally remove the lot and build a new stud wall, but that'll obviously open up the bathroom into the adjacent room temporarily. If you're worried about losing room in the bathroom, then you may be able to loose a bit in the adjacent room.
    If the shared wall has a door into the bedroom on it, then you may need to create a very shallow reveal at the door. Floorplan would be useful.
  5. Wayners

    Wayners Active Member

    HardieBacker from B&Q it is a cement backer board for tile and stone to be used as a replacement for plasterboard or plywood. Then tile.. Youtube has some info on the stuff..6mm is fine but I sometimes use the 12mm..
  6. longboat

    longboat Well-Known Member

    Ah, the dreaded egg box walling. Could be worse though, at least you haven't discovered compressed straw underneath.

    Not as bad as it looks to be honest, just remove the plasterboard skin in the bathroom and dodgy and dab new plasterboard to replace. Tank the showeright area and tile as normal.
    No need to take the whole wall down.
  7. markh1

    markh1 New Member

    Thanks for the replies, baffles me the measures housebuilders take to make savings, even not tanking the walls. I'm thinking of ripping out appears the best solution, will reduce the bathroom size. May solve my other issue as the shower space was 870mm and was considering a 900 mm tray put into the wall to fit, adding a normal stud wall may mean I'm left with 800mm space which is standard tray size. Will need to do some measuring!
  8. markh1

    markh1 New Member

    I did consider this at first but not sure much left to attach the plasterboard to as not that many wood beams. Is it better to get standard board and tank or just use aquaboard? Or is this just down to personal preference and budget
  9. longboat

    longboat Well-Known Member

    The number of beams doesn't really matter as you'd be dot and dabbing the new boards on top. Use screws where you can if needs be but they're not really essential.
    12.5mm plasterboard, bonded and tanked will be more than adequate for a domestic shower area.
    Personal preference and budget considerations do come into it but sometimes you need to step back and ask yourself if you're over-engineering things just for the sake of it.
    CGN likes this.
  10. CGN

    CGN Well-Known Member

    Aquaboard/Hardie backer is certainly a superior material in this situation. However, IMHO, if the walls have little flex, tanked PB will also be fine.

    Caber flooring/t &g chipboard has become the norm in many houses over the last few years. If fitting a shower tray, take it up and fit marine ply or a modern equivalent such as Hardie floor. If a bath, then whether caber, standard floorboards etc, I always add a plank of timber under the feet to help spread the load and stiffen up this area.

    Any stud walls need to be as solid as poss...extra noggins if required. Extra important at the base of shower tray.

    If using plasterboard, tank walls, then silicon bath or shower tray to wall.
    Full bed of quality tile adhesive, grout then silicon. If grout of silicon fail, PB is protected from moisture.

    If grout/silicon fail on aquapanel etc, then tiles may still become loose, leks occur, but the board itself will dry out and can be re-tiled. You don't get this with un-tanked PB.

    Other advantage of aqua panel, is it can carry more weight per square metre...useful when using paving slabs on the wall :D
    longboat likes this.
  11. markh1

    markh1 New Member

    Ha, I do have a habit of over engineering things!

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