Condensation and mould in 1930s semi

[AnotherEmma]

I have an annoying condensation and mould problem that's been going on for years and I am determined that this is year I will get it fixed.

DH and I have many talents but DIY is not one of them and I was hoping to call on mumsnet's collective wisdom for advice.

The house is a 1930s semi with external wall insulation that was installed about 5 years ago. The condensation and mould are in the two first floor rooms at the front of the house.

One room is a bathroom with 2 external walls, it gets cold. We installed an extractor fan with a humidity sensor a few years ago. DH scrubbed the ceiling with mould treatment and painted it with anti-mould paint. These two things seem to have helped a bit but the mould still grows. One problem is that we have to dry laundry in the bathroom in the winter (nowhere else to dry it) but we do run a dehumidifier in there pretty much constantly during the day (not at night because the noise disturbs me).

The other room is a bedroom with just 1 external wall with a bay window. (One wall is adjoining our neighbour's property). The bedroom had a fireplace which was blocked in by the previous owner with no ventilation. The worst mould is inside a built in wardrobe where there is obviously even less ventilation than the rest of the room.

It seems obvious that ventilation is the problem but we don't know how to fix it. DH spoke to a builder who suggested that the loft insulation might be a problem, if there isn't enough of a gap to allow air flow.

We have got a few quotes for damp surveys and we're willing to pay for one if necessary but I am wondering if there is anything obvious we are missing that we should try first.

@PigletJohn I hope you don't mind me tagging you but I have seen your posts on other threads and hoped you might be able to advise please?

Photos of bathroom

Photos of bedroom

Have you heard of a positive input ventilation system? (PIV fnar fnar ) I don't know the costs but I have friends who swear by them.

My suggestion would be a tumble dryer. Not hanging washing inside can make a big difference.

Do you have air bricks? Are they clear? Our 1930s semi had them but previous owners had let plants grow over them at the front of the house so they all needed clearing

northern fnar fnar indeed Thanks, I'll look it up.

Many We have a washer-dryer but it shrinks things (even on a low setting for a short time) so I only really use it for sheets and towels. Also not all clothes can be tumble dried. We are planning a ground floor extension with a utility/laundry room so we won't be drying clothes in the bathroom for ever, but I think the condensation/mould problem will probably persist - I don't think it's the only cause because we have problems even in summer when we dry laundry outside.

Was about to post same as @Bellesavage

Have you tried purchasing a dehumidifier? Then running it at first all the time, then popping it on when doing washing etc.

Mould only appears when ventilation is poor
, so I agree with checking ventilation bricks. Drying washing indoors ,as others have said, will make things worse.

Try to keep front and back windows open so that there is proper air circulation ( not easy in this country I know) .

Belle and LIZS
Thanks both. We probably had air bricks before but it looks they were covered when the external wall insulation was done. I've just checked and there are none visible.

Photos show front of house, bottom and top (bathroom window). They are brick slips.

I have long suspected that the external wall insulation created the problem or made it worse

Jessie you might not have read my latest post when you wrote yours - we do own and run a dehumidifier, but it hasn't solved it.

A lot of new build flats have positive input ventilation.
For old places with double glazing and limited ventilation
they are a game changer!

Interesting... looks like PIV could be the way forward

(I am clearly not adult enough for this!)

If you can afford it, damp survey will cost about £250. I think it's worth it as they know their stuff. Don't bother with a free survey from a damp proofing company. They are just looking for rising damp.

We've had quotes for £90-125 + VAT but all from companies who would then do the work. I have made some enquiries to independent damp surveyors as I realise that would be better.

From the reading I've just done is seems as if PIV could be a relatively low cost solution. But I'm wondering if we need heat recovery ventilation in the bathroom (as it gets cold in there). I also think we could do with adding ventilation in the fireplace in the bedroom. I wonder if we need to do all three. Overkill perhaps?!

I am concerned about the built-in wardrobe because we clearly need to ventilate that somehow; the mould on the wall is bad and I don't know how the clothes aren't mouldy

We have the same issue. Mould everywhere. Ventilation hasn't solved it. I don't know what to try next.

please show a photo of your extractor fan, so I can see what sort it is, and how close to the ceiling.

Where does the fan vent come out? I can't see it. Does it have flaps, and do they open when the fan runs? Does the prevailing wind blow against the vent?

I am not keen on humidity fans and will suggest you leave the fan running continuously.

The ceiling mould looks to me like there is unsufficient, or no, loft insulation. Does the ceiling slope?

Have a look in the loft. Is there any sign of leaks in the roof or underfelt (if any)? Or of missing or slipped tiles (may be further up the roof than the damp patches)? What sort of roof does the bay have?

In our house: Opening windows at night in the bedroom (just a crack) helps, the front windows don't have ventilation. And also immediately after any shower or bath. Strangely the downstairs rooms don't get so cold and we dry washing in there with no condensation problems

The house is a 1930s semi with external wall insulation that was installed about 5 years ago

Did you install that or was it there before you? Was there mould before that?

We installed a PIV system in our loft and the difference was spectacular. We used to have condensation pouring down the upstairs windows all winter, despite running a dehumidifier all day. Worth every penny.

I have some similar issues and ours affects the rooms attached to one particular wall. We've tried lots of different things. We have an envirovent extractor which I thought would be the business as its quite expensive, we've got the air bricks too, and run a very decent dehumidifier. Several experts reckon ours is that the affected wall is one that gets all the weather plus we have a disused chimney on that wall. We have original 1930s tiles which we have to get replaced in the next 12 months as a mortgage condition through Skipton as they contain some asbestos, furious at first but maybe this is a good thing as the roof has no lining and you can see daylight when you go into the loft! The bathroom mould issues are much better since I've prepped with mould primer and then painted in eggshell paint. We have 2 windows, 2 external walls and lots of tiles and the room is also freezing with condensation dripping down walls after showers etc. I think our rubbish modern towel rail is a culprit here as I don't think we are achieving the correct BTUs for the room with the current radiator so I want to get it changed ASAP. Do you only have a towel rail radiator too?

Watching this as have exactly same problem.

PigletJohn
Thanks for your reply.

Here are photos of the vents in the bathroom ceiling and at the side of the house. The bathroom vent is in the ceiling directly above the shower, and the fan itself must be in the loft - I'll check what we have. I believe it runs through the loft and out via a vent in the soffit (is that what it's called?)
You will see in the photo that there is a small window but it's actually been tiled over from the inside (done by previous owner, not our choice!)

I don't think there are flaps but that's just from looking, I don't have much idea what I'm looking at I'm afraid

The ceiling does slope, at the edges of the ceiling that meet external walls - attached photo shows the corner of the bathroom ceiling where there are two slopes.

We do have loft insulation but perhaps not enough and perhaps it doesn't allow enough air circulation?

I haven't had chance to look in the loft yet but will look and report back.

Looks like the bay window has a flat roof - see photo.