Mould issues. Open up chimney?


17 May 2012
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United Kingdom
OK, so I am in my new home - a 1930s bungalow. As suspected, there are signs of black mould around the house. I suspect that this is due to lack of ventilation rather than water getting in though, as there is no mould near windows, chimneys, ceilings etc. Its all in corners and edges of rooms where there was furniture. The house has limited ventilation, with just an extractor fan in the shower room (nothing in the kitchen). There is also no radiator in the kitchen or the hallway area. The lounge has black mould in the corners either side of the chimney (outside walls), The chimney has a panel with air vent, but I am thinking, would I be better off just removing that panel for improved ventilation? Also, if I got the chimney cleaned (I just looked up there, does that look normal, or is that some sort of nest????) would I be better off installing a quiet (ideally, silent!) extractor fan that can just extract all the time, onto that panel? I suspect that the previous owner, who was about 80 years old, used to keep all the windows closed to stay warm, and the kitchen door open get help get heat into it. Also, her oven was broken, and she was using an electric hob, so probably a lot of pans on the boil too! Oh, and no trickle vents on any windows either.

I need to put something in the kitchen too, but unsure whether to have a hood above the hob, or just get a big extractor fan that could be on a timer (say, always in mornings and at dinner time, regardless of whether we're cooking or not).

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keep in mind that a 1930's home may well have leaks. the water supply pipe might have pinholed by now, and if it is in a concrete floor, you may not spot it, until you take up floor coverings and find damp.

Anyway, with modern plumbing, you may benefit from a new, larger supply pipe, to get the best out of an unvented cylinder or powerful combi, so worth thinking about as you do your renovations. It is very tiresome if you have to do it after the floors and decorating have been done.

As for the kitchen extractor, modern ones can be very powerful. I favour a multi-speed canopy that you can leave running at a whisper, and turn up once you start frying onions. Again you will need to make the hole in the wall before you do much decorating.

The bathroom will benefit from a ducted inline fan, which can be powerful and quieter than cheap old fans. It goes in the loft, above the ceiling, which also helps muffle the noise. Unfortunately, speed controllers are surprisingly expensive, so have it come on with the light switch with a 10 or 20 minute overrun.

Every disused chimney flue needs to be ventilated top and bottom. Preferably a ventilator that does not have the facility to close it.
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Thanks. The mould is also on the dry side of the house - all the plumbing and drainage is down the west side - the front faces north. Also, all suspended timber.

We should probably replace the pipe though - came up on the survey that it might be lead. Spoke with a neighbour since, they replaced an iron pipe with plastic this year.

I like the sound of the multi-speed canopy that is on all the time, this will probably solve most problems - can you recommend any in particular? I have a big SDS drill, so just need a big bit for making big holes! Are most ducts 10cm diameter?

Bathroom has a fan in the ceiling with a cord to power it, separate from the light. I was wondering if there was a fan with humidity sensor built in that would come on when needed?
Mould behind the chairs and in the corner, is normally indicative of cold walls, and not enough heat and ventilation. It'll depend on your budget as to how you deal with the problem.
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I assume that pumping up the heat to keep it dry is the obvious solution?
Often, but not always; in a lot of cases, it's the lack of air movement that causes the mould issues. If you've got brick walls without a cavity, then they will always be cold, and as you don't have the heat on permenantly, they will get cold overnight.
interesting, i read the other week about how keeping heat on all the time in these houses can eliminate damp and does not cost loads more either - and cheaper than cost to refurbish everything.
You'd need to run an experiment, but I suspect you'll still find it costs more, and as to long term, it may still be cheaper to slap on some external insulation, and get a wood burner. I did the ex's place for her, and it cost about £6K including the stoves, and she hardly had the heating on last year. But it's certainly added to the value of the house, so it's an individual judgement call for each to make. In your case, obly being a bungalow, then job should be a lot easier and cheaper. Actually, whereabout in Essex are you; if you're intereted, I'll see if the guys who did the top coat for me are interested.
Are most ducts 10cm diameter?

not any more. 125mm and sometimes 150mm

I am very fond of Elica, but email them and ask for their glossy brochure.

If you try to research using their awful website, you will see why.
Sounds the right era to be solid walls, in which case you will want to either insulate the external walls from inside, or outside. It's expensive, but makes a WORLD of difference. We had it done on our bungalow, along with removing the floor boards, fitting celotex, and refitting ply, and topping up the loft insulation.

The winter before we did it was horrible - cold, no matter how high the heating was set, and mould forming up to waist height in the bedroom, and behind anything even remotely near to the walls in other north facing rooms. In the bedroom i left a 20cm gap behind the wardrobes and ran a fan every morning behind there to move the air, but every Saturday i was bleaching the wall to clear the mould.

After insulating externally, the only mould I have had is in the bedroom in the corner, as the insulation only went as far as the soffits, so there is probably a cold spot above them, before it meets the loft insulation. The heating bill has halved, the house is warm, and generally a pleasant place to be.

It did however, cost £10,000! But money well spent I think.....
Does Jersey get that cold in the winter? I've never been, but thought it had mild winters.
I think I will just have to put up with a crappy and expensive winter... hopefully by winter 2018 we'll have an extension and the cold, damp rooms will be renovated by then.
Does Jersey get that cold in the winter? I've never been, but thought it had mild winters.

Not especially usually, and the unpleasant winter was pretty mild even for here, but it was still not possible to keep warm. Would be even worse further north!!
Had our first slug last night! Only saw it when I opened the lounge door which ran over it. Looks like it came from the chimney, the slithered all round the edge of the sofas towards the doorway, I guess hunting for food towards the kitchen.

Maybe the damp musty smell up the chimney was slugs? Running the dehumidifier in the room, still have fire place open, and windows on catch, humidity still at 55-59 with people in the room. Wondering if the chimney is a problem? Will be removing it eventually to make a bigger room.

Curious to know state under the floor now though, in case there are more problems below. Surveyor suggested we needed more air bricks.

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