Condensation Issue (Black Mould) help!!

[jim1980]

ok go easy on me this is my first post.
quick background on my problem, moved into a 2 bed bungalow built in 1955 about 8 months ago which has a condensation issue which causes black mould in certain parts of the house. We have a conservatory that runs the length of the back of the house so that ads to our problem, we also have a blocked chimney in the lounge and i have found 2 air vents blocked (covered over with tiles) in the kitchen and one blocked in the bed room. We have an extrator fan in the kitchen but its one of those that just circulates the air not sucks it out and there isn't one in the bathroom. The kitchen, lounge and bedroom is where we have the mould issues and there is a tiny amount in the bathroom.
Now as i mentioned earlier we also have a conservatory that runs the whole length of the back of our house so when opening the kitchen, bathroom and spare room window we are opening them into the conservatory so its hard for any steam or damp to escape. (however the spare room does have an air vent up high in the rite spot which does go outside and this is the only room in the house which is black mould free)
We have had 2 damp specialists round and they confirmed that its black mould and nothing more which is good.
They have reccomended to us either one of these positive pressure vent machines plus 1 passive air vent in the lounge OR go down fitting a passive air vent in the lounge, open up one in the kitchen and fit with a passive vent and the same with the main bedroom. They have also said opening up the fireplace, fitting humidistat devices in the kitchen and bathroom will also help.
What im after advice for is, is it worth paying out for the passive or positive pressure vents or would it be better and more cost effective just to open the ones that are blocked, and open up the fire place (which we want to do anyway) and also fit hunmidistat devices in the kitchen and bathroom (again which we wanted to do in the first place) the reason im thinking this route is because of what i said above about the spare room, it has a vent in the correct place and it does go outside and has no black mould. (PLUS and i know this is bad we dry our washing in the spare room and still no damp!!)
Any advice on what i've said about would be appreciated and any advice on the passive vents or the positive vents would also be appreciated.
Sorry if i've rambled on, i just wanted to make sure i covered everything in the first post.

 

[Burnerman]

Hi Jim, the first things to address are the areas where the moisture is initially produced - i.e the kitchen and bathroom. The fact that the mould growth is limited here is due to these places being essentially warm - the moisture moves until a cool area is found for it to condense.
Ventilation is what you need.....a bathroom extractor fan is vital - especially with a timer fitted so that it can run for 15 mins or so after being turned off. An externally vented kitchen hood is next - these recirculating ones may trap smells etc but they don't prevent water vapour. Personally I would consider both of these proposals if possible, before opening up fireplaces, etc.
John

 

[jim1980]

Burnerman, thanks for the advice, we want to open the fireplace anyway so we can have a fire so that will happen no matter what and we have been told doing so will help an awful lot as its basically a massive vent.
definitely going to go down the humidistat route in the bathroom and kitchen, cant work out why the old residents blocked up the air vents didn't fit an extractor in the bathroom and only a re-circulate hood in the kitchen, very odd.
Basically want to almost elimate the damp causes before we start to decorate. So any tips advice on what i've said above would be great.

 

[Burnerman]

Opening up the fireplace will be a great help, but of course you'll have a gale going up there whether you want it or not...you'll also have to ensure that enough combustion air can actually get into the house.
Open all air vents, and check there are no blocked up air bricks outside.
Sort out the bathroom and kitchen extraction, use a tumble drier for the laundry if you can and personally I don't think you'll need anything else.
John

 

[jim1980]

Burnerman, like i said above i have found 3 air vents that are blocked which i plan to open, add the fireplace being opened up, and the kitchen and bathroom fans being fitted, im thinking the same. Our next door neighbour who are attached to our house have no damp issues, (their house is the same as ours) they have a fireplace open and all their air vents open. Weird why people block vents which are there for a reason.

 

[Burnerman]

People who block air vents off really haven't a clue what they are doing...ok, in the good old days when there was a coal fire in every room, then too many vents through the wall - when the fires had gone - produced too much draught, so sealing a couple of these off was ok.
As for blocking off air bricks - the next thing they know is that they have dry rot
Good luck with your projects!
John

 

[JohnD]

Air bricks are great but if they open into rooms, people complain about draughts.

Start by installing and using extractors in kitchen and bathroom, preferably centrifugal in-line ones installed in the loft and turned on automatically when the lights come on. Ducts in unheated areas like lofts should be rigid pipe (not flexible) with a slight fall towards the outside so condensation does not run inwards, and flop loft insulation over the ducts to keep them warm and discourage condensation in the pipe.

//www.diynot.com/wiki/building:condensation_in_houses

 

[foxhole]

You correctly identify all the causes in you first paragraph, most ventilation is free so open all vents and fit fans as already suggested, avoid fans controlled by humidity stats as they are inefficient, they are triggered by humidity, you want the fans to run before the humidity levels get to a level to trigger them, in short if the room can produde moisture [kitchen/bathroom] the fans should run with every use.I use a movement detector in shower room to ensure constant ventilation when in use with a timer run on to ensure good ventilation.