How To Make A Cold Bathroom Ceiling Warm, To Help Banish Black Mould

img_5950Not the most glamorous of images I do realise, but you know me, getting stuck into the practical stuff is what we’re all about! If you desire encaustic tiles and brass taps, head over to pretty Pinterest forthwith. But, if you have a problem with repeated black mould on a bathroom ceiling or wall, then I might be able to help.

Black mould in bathrooms, don’t you just hate it. It’s so annoying, settling in the grout lines between tiles and the sealant in shower cubicles, becoming ingrained and almost impossible to remove if not cleaned off regularly and thoroughly. Most of the time the growth is eminently preventable (see later in this post), but sometimes conditions in the room really don’t help. Aspergillus Niger (AN) grows when water molecules are set loose in the air and seek to find a cool, organic spot to condense onto. Here are some examples:

  • In a warm, wet bathroom, AN forms in grout lines, on sealant or on cold walls or ceilings, like the one above in one of my rentals, which is quite an extreme case. It can appear just on corners, or if not dealt with, cover the whole ceiling. It’s caused by water molecules from bathing or showing endlessly circulating in the room instead of being allowed to escape outside via open windows or good ventilation fans.
  • In bedrooms, it often appears in low down corners, behind cupboards or in wardrobes. It’s caused by moisture created by us, our sleeping bodies, and when that moisture can’t exit the bedroom via vents or slightly open windows.
  • In other rooms of the house, it’s usually low down on walls or behind furniture where the flow of air is poor and stagnant air is gathering. This is often due to washed clothes drying in the house, on racks or radiators, without good air flow.

Black mould doesn’t usually form in dry, adequately & well heated, properly ventilated houses which are regularly cleaned. Houses which are well maintained and where both the owners & inhabitants understand the necessity for these balancing factors. I say this as a landlord with 17yrs experience seeing how houses and apartment behave entirely differently according to their inhabitants. Seriously. If a tenant acts like a responsible homeowner, mould rarely forms, and if AN does rear its ugly head, it’s generally because a room is relatively compact and naturally has stagnant corners.

However there can be factors which can make it extremely hard for a homeowner or tenant to keep on top of mould growth – cold walls or ceilings. The ceiling we’re working on this week is exactly that. The area above is a little too well ventilated in an inaccessible roof space and is very cold in winter, so cold moist air condenses on this cold surface and black mould grows like mad. img_5949-e1532418294475.jpgNow at this point I’ll say that in 14yrs renting this particular property, this has never happened to such an extent before. The exiting tenant was rather partial to Insanity keep fit videos in this compact studio and repeatedly showered, rarely had heating on and rarely left the flat. The result – massive amounts of trapped moisture all looking for somewhere to condense. If you see a big change to a property, look not only at the bricks and mortar, but also to lifestyle issues which have a huge impact. Even though the tenant or owner will be incredibly affronted to be gently informed of the same.

I’d washed the ceiling with the bleach and water solution but this merely took off the top layer of mould, leaving a heavy grey stain on the paint. I could have simply painted over it with a stain block like Zinsser BIN and then used a regular white emulsion but it was clear that this cold ceiling could be an issue again so we’ve taken much more comprehensive action.

Rather than take down the ceiling – with all the filth and loft dirt involved – we decided to construct a slightly lower stud frame and attach it to the ceiling joists above, which I could find by popping my hand up through the spotlight holes but you can also find using a small pointed tool like a bradawl. Mind those lighting cables though eh!.
img_5947The ceiling is quite high in this shower room so adding slightly lower ceiling didn’t impact on the room at all. The point is to create a warmer ceiling, insulated in-between the timber frame, to dissuade the condensation problem as a much less cold ceiling won’t be so attractive to the water flying around in the air.

We could have used soft loft-type insulation to create the warmth but had some 50mm rigid Kingspan insulation left over from another job and cut this to size using a tape measure & regular saw. If you measure and cut carefully, the infill blocks wedge nicely. I had to saw the rear foil-backed side off my infill blocks as the timber frame we used wasn’t quite 50mm deep, so the insulation blocks were sitting slightly proud of the frame. You don’t get this issue with soft insulation but as I say, we had some rigid over and I don’t like waste!

Make sure you mark or measure where any lighting cables are too. This is one of the reasons why I like the rigid insulation, because it sits snugly into the frame and I can cut a hole where the three IP rated spotlights sit. Soft insulation needs to be held back from spotlights or dangerous heat can be created around the fitting.img_5951You can see how the frame sits on the ceiling, then the insulation between, then finally the plasterboard is fixed to the frame. I had some pieces of 22mm Knauf  insulation board (which I always use) going spare and these worked a treat, adding even more warmth to the new ceiling. You can buy this in sheets from any DIY store, just as you can the soft roll insulation. This isn’t a necessity when you’ve insulated in the stud as well, but every little helps. You could use regular 12mm plasterboard if you wanted.

The ceiling is all ready for skimming now and when finished will help stop this very ugly problem happening again. That and not taking on a tenant obsessed with Insanity videos obviously.

If in your house this mould growth happens on a cold wall instead of a ceiling, for example if your bathroom faces North or East and thus the external walls are rarely heated up by the sun, or if the wall construction is solid or finger cavity and thus colder than newer ‘proper’ cavity walls, then you could think about taking off the plaster when renovating and using insulated plasterboard to re-board. You don’t need to construct a timber frame on walls, the plasterer will simply dot and dab the boards onto bare brick, meaning a bit of an air gap between dabs of adhesive, then the polystyrene layer on the back of the board for warmth and then the plasterboard itself. I’ve done this for clients – it really really does work.

I talked a lot more about insulated boards in this previous post HERE, back when we were living in one room mid-rent here at Moregeous HQ.

Oh, and the other thing, if you get black mould in your home, please don’t panic. It only really becomes dangerous when it’s excessive and for people with several lowered immune systems, eg with leukaemia or HIV, so for most of us it’s a problem that can be easily avoided by the following:

  • Ventilate your home, air it, open windows, open doors. get some fresh air in!
  • If there’s a bathroom fan, always use it when showering or bathing. Switch it on five mins before you start showering, and leave it running for ten minutes after you finish. Slightly open a window and leave the bathroom door
  • Rise down the walls of your shower after you’ve finished washing. All that dead skin and soap scum will just sit on the tiles and help mould grow otherwise. This is a really fantastic  habit to get into.
  • Leave the shower door open after showing to allow air to circulate in the cubicle.
  • Leave the bathroom door open to help fresh air get in the room and not circulate endlessly in the room.
  • When you do first start to see black mould forming, usually on the sealant at the bottom of showers or behind taps, use CIF and a toothbrush to have a scrub at it. If you’ve been a bit lax and it’s been there a while, you might need to use bleach. I pop some on a toothbrush and carefully apply to the sealant, but only around ceramic or porcelain tiles. Avoid using bleach around encaustic, natural material or marble tiles though! When black mould has gotten really bad on sealant, you’ll simply have to cut it out and re-seal I’m afraid.
  • Hang damp towels up on a rail or on – my best tip – those clippy trouser hanger and then hang the hanger from a door casing so the damp towel is free to dry all day whilst you’re at work. Nice dry towels, no musty smells, doors left open. Boom.
  • Leave a window slightly ajar when sleeping, or leave the door open to ensure body moisture isn’t trapped in the bedroom. Most double glazing windows have a trickle vent – open them. And tidy up in cramped bedrooms – piles of stuff just encourage stagnant air and mould growth!
  • Dry clothes in rooms with good ventilation, next to an open window. Not in rooms with the heating on and doors & curtains closed. Damp air which leaves your clothes and then becomes suspended in mid-air searches desperately for a cold spot to condense onto. Let it escape outside. Or better still, fit a clothes line outside, or ask your landlord to!
  • Open a window when merrily bubbling pasta or veg on the hob, all that moisture needs to go somewhere.

Right, that’s enough bossing you around. I’ve got to get back to finishing off taking down a wall in the kitchen and wallpapering in the living area. No rest for the wicked here! Pop over to the Make It Moregeous Instagram to watch us do all of this kinda stuff and much MUCH more live and direct 🙂

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