Persistent damp/mould on brand new ceiling. Please help.

Discussion in 'Painters' Talk' started by Superv8, Dec 9, 2016.

  1. Superv8

    Superv8 New Member

    Hi there,

    I'm having an absolute nightmare with my bathroom ceiling, any advice would be greatly appreciated.

    I've tried to tackle the damp a couple of times with little success, hence the slightly long story. I'll try to summarise it as best as possible:

    Recently moved into a new property, renewed all the plastering, plasterboard ceilings and skimming. I waited approx. a month or so with adequate ventilation prior to painting. Having read several forums I decided to apply watered down matt paint, before applying 2 coats of Dulux vinyl matt.

    I installed 2 extractor fans in the bathroom, one directly above the shower and the other above the bath.

    Shortly after using the shower for a few weeks I noticed damp stains beginning to appear on the ceiling above the shower, so I made sure the family would switch both extractor fans on before using the shower. This didn't help much. We ended up wiping the damp stains every time they would appear, which was becoming quite frequent.

    Sometimes when using the shower or on the rare occasion the bath we'd notice water droplets gathering on the ceiling and down lights! The ceiling was gathering all the moisture. At times when I'd be busy renovating the property and would ignore the bathroom ceiling for a few days the damp would get so bad, it would cover almost half of the ceiling. It would look like something out of a horror movie.

    So eventually having freed up some time I decided to tackle this, I first wiped away the damp stains. Thankfully it was on the surface and had not penetrated the paint/skimming. So I was left with a slightly off white ceiling with a few ashy looking stains. I gave it a day or so to dry. I then sprayed on Polycell 3-in-1 mould killer and again tried to wipe away the remaining faint stains. Again waited a day or so to dry. I then painted the ceiling with Polycell one coat damp seal.

    For the next couple of weeks I thought I had successfully conquered the damp, only for it to reappear, but this time didn't seem as bad (please see pictures provided, it actually looks great compared to the first time round..). It seems the stains/marks have now somewhat slowed down with a small crack in the paint, it doesn't seem to be spreading, perhaps getting a little darker? The marks were originally light pink'ish in colour and now as you can see from the pictures they have darkened over time. It can't be wiped away easily anymore, unless I attempt to scrub it. I am still getting water droplets on my ceiling, despite switching both extractor fans on and opening the window a bit for ventilation. By the way we don't have hot steamy showers, perhaps warm to hot, nothing excessive, particularly since this whole debacle started.

    It's now been a few months, I've completed the property. Now I can focus on this irritant. It really has done my head in, knowing the effort and time I've put into the property, it's also a bit embarrassing showing family and friends the new family bathroom!

    Being bit of a novice I'm obviously making a stupid mistake somewhere. I'm guessing part of the problem is possibly due to how low the wall extractor fan is. Thus the steam lingers below the ceiling but above the extractor? But still 2 extractor fans running simultaneously with the window open should surely get rid of the moisture? Perhaps its to do with the paints applied? Maybe I've completely sealed the ceiling therefore it's unable to breath? As you can see, I haven't got a clue..

    Apologies for the long story, but I wanted to try and provide as much detail so perhaps someone can pick up on where I've gone wrong.

    Again I would be extremely grateful if someone can provide any assistance. Many thanks.

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  2. sospan

    sospan Screwfix Select

    Since all the smudges on the paint work are around the edge. It could be that warm air is going up through the ceiling lights and then condensing on the roof above the bathroom ceiling. You then have a combination of drips and it running down the roofing felt to edge of the roof.

    A simple test would be to fit some thermal shrouds to the lights - http://www.downlightatticseal.com/default.html?gclid=CLe01Nn85dACFRUTGwodPB4Lkg
     
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  3. DaveF

    DaveF Active Member

    Looks to me like the problem is the ceiling, not the ventilation. I suspect that the ceiling may be cold, which is causing the problem. Get above the ceiling and check the insulation.
     
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  4. CGN

    CGN Screwfix Select

    As Dave said, check to see if you've got sufficient insulation above ceiling. Looks to be quite a big bathroom, so Id be looking at fitting an inline fan in the loft with a vent in the ceiling. Given your roof, you would need to run ducting out through the soffit.
     
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  5. b4xtr

    b4xtr Active Member

    Agree with others, it could be a lack of insulation, making cold areas, or the fans are pushing the extracted warm/moist air into the roof void rather than outside
     
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  6. I agree with b4 who agrees with others...

    That looks like a VERY cold roof.

    You simply shouldn't have this much condensation forming on it, not with a window cracked open and the extractors running as they are. Do your wall tiles run with condensation? Does you bathroom mirror mist up?

    (If your mirror mists up badly, then I suspect you are either producing shed-loads of 'steam' (which you are not) or else your extractors are pants. If your mirror is not steaming up badly and yet your ceiling is running with water, then there's your issue - your ceiling must be stone cold. Bludy freezing.)

    The slopes in the corners - and that beam - indicate it's right in to the eaves of your hip roof (that's doesn't mean it's 'cool' in a 1970's way, only that it's 'hipped'...). But it will almost certainly be very cool in a cold way as the eaves will be allowing an icy draught right up them slopes and in to the loft (as it should).

    These sloping parts of your ceiling are likely to have very little space up above it - ie betwixt the upper side of your ceiling and the underside of your roof covering (slate or whatevs) - and if you were to stuff insulation down there it would risk blocking off the required - vital - attic ventilation.

    So, assuming this is all down to condensation due to it being by far the coldest surface in that room, what can be done? Either a super-powerful extractor that will effectively remove the moisture before it has a chance to condense out, or else add a layer of insulation to the underside of your ceiling.

    The sloping surface limits your choice here, I think. I'd be inclined to try WallRock which is only 4mm thick, and add two layers of this - at right angles to eachother. It should leave a surface which is ready for painting.

    If you go for this type of solution, then I'd suggest not using that room for a few days whilst the job is done - at least not using it for showers/baths. Also, get a heater in there to dry it out fully.

    Scrape off all the loose paint and then give the ceiling a good coat of Everbuild 406 Stabiliser to seal it - this will soak in and seal any bare plaster and also seal and prime the painted parts. Then apply the insulating roll following their instructions to the letter.


    (As said in posts above, the presence of actual stains does suggest that some of this is coming from the 'other' side of the ceiling, but I suspect it's still down to condensation produced in the bathroom rather than a leak of any sort in the space above. If it were down to a leak in the roof, you wouldn't have these beads of water forming and running on the ceiling, but would instead only have damp patches and stains appearing. I suspect the condensation is really penetrating that ceiling material (is it plasterboard or plaster-on-lathe?), missing with the gunk in that plaster or coating the surface above it, and then this seeps right back.

    If you can, you should try having a look up there chust in case - is that possible? Take a torch and a camera. You could also add loft insulation to much of that ceiling above, provided you don't block the eaves.)
     
    Last edited by a moderator: Dec 9, 2016
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  7. Mosaix

    Mosaix Active Member

    I take it that the sloping ceiling is where the roof line comes down close to the ceiling - the most difficult place to install insulation.

    Just a suggestion - maybe completely stupid. A layer of foam backed plaster board over the existing ceiling in those places with a plaster skim over it.

    Nice looking bathroom BTW.
     
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  8. Superv8

    Superv8 New Member

    Apologies for the delay in replying, completely overwhelmed with work.

    A big massive thank you to everyone, you guys have no idea how grateful I am (and how dumb I feel).

    It makes complete sense, the general consensus being a cold ceiling, lack of insulation.

    From what I remember that was the only part of the loft I did not board up, as I was going back and forth tweaking the shower plumbing, installing the extractor etc. For this reason I don't think I insulated that particular area well enough with Rockwool and certainly did not insert any insulation above the sloped ceiling, to be honest I can't quite remember if I can even gain access to that area... will check tonight (packed with boxes/suitcases ).

    I think perhaps the first call of action having checked the loft is to lay down sufficient Rockwool, maybe two layers, bearing Devil's advocate advice in mind, leaving appropriate room for ventilation near the eaves. Also maybe look into purchasing a pack of 6 thermahood's as sospan suggested for the down light's. Scrape of loose paint> fill uneven surfaces> apply 406 Stabilising Solution and finish with a coat of Dulux vinyl matt OR Polycell one coat damp seal?

    I guess if I can't access the sloped ceiling area or there's not much space in-between then I have no choice other than to further insulate the ceiling, with WallRock?

    I appreciate the help and advice. Thanks.
     
  9. Superv8

    Superv8 New Member

    Was wondering won't the joins be visible mate?
     
  10. koolpc

    koolpc Super Member

    Try to get into those areas and insulate. If you cannot, if it were me? I would take the ceiling down and do a good job of insulating before re boarding. Obviously, if you have the height you could put in a suspended ceiling with insulation in between. Plus, inline fan ducted out is a must
     
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  11. It isn't cheap stuff, I should warn you. It is designed to be easy to apply, give a useable level of insulation, but also be ready for overpainting.

    One side will be rough, but the finished side has, I understand, a smooth finish with neat edges that will butt up against eachother to be neat and seam-free.

    There are much better alternatives, of course, but they tend to be thicker rigid sheets which will not conform to your curves.

    Have you - can you - have a look at the void above that ceiling? If you can take some photographs perhaps we can suggest if insulation can be added up there too.
     
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  12. b4xtr

    b4xtr Active Member

    don't miss any areas when insulating or the dodgy patches will keep re-appearing, will be interesting to see what you find/do,good luck
     
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  13. Astramax

    Astramax Super Member

    Wrong paint used......use Dulux Diamond Eggshell or Crown 'Extreem' if you prefer a matt finish. ;) Give the paint a chance crikey you have a Monsoon shower head, all that steam and humidity is the problem, matt paint will get damp in that situation and eventually fail, simple.
     
    Last edited: Dec 12, 2016
  14. BMC2000

    BMC2000 Screwfix Select

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  15. Astramax

    Astramax Super Member

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  16. Superv8

    Superv8 New Member

    Finally managed to take a few photos. Hope this helps.

    Try to ignore the poor workmanship! To be fair I thought the Rockwool insulation (that I laid down approx. 9 months ago) would be in a worse state than it is..

    The entire loft has been boarded, just the area above the bathroom remains partially covered, as at the time I needed back and forth access. Having completed the bare necessities I never really paid it any further attention, leaving it in it's current state:

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    The beam that's visible within the bathroom (in the corner)

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    Close up of the corner

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    Rockwool gathered, on left side is the shower plumbing and on the right is the down light. Shower extractor vented out via the soffit.

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    Most importantly pics of the area directly above the damp/ curved ceiling bit

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    Approx 3" gap, old felt is sagging a bit

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    What should be my best course of action? Reading the above replies there seems to be quite a few options, I'm a little confused.

    Should I place/stuff some insulation into the eaves/over the curved ceiling bit (above the bathroom only), with the risk of restricting ventilation? The loft is quite a bit drafty as is. Not sure.. Hope the above pics help. Many thanks.
     

    Attached Files:

  17. KIAB

    KIAB Super Member

    Last edited: Dec 13, 2016
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  18. b4xtr

    b4xtr Active Member

    The sloping part could be a "mare" to properly insulate while maintaining an air gap under felt.
    Someone said in an earlier post that you could apply insulation/plasterboard & skim the slope from the room side, given that the ceiling needs work i think i would be looking at that option. the flat part of ceiling can be addressed from the loft, then use the correct paint
     
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  19. KIAB

    KIAB Super Member

    It would have been the best option, using a foilback insulated plasterboard.
     
    Last edited: Dec 14, 2016
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  20. CGN

    CGN Screwfix Select

    Been a busy bee :)
    Just checking, you have taken your ducting to a vent cut into the soffit?
     
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