Fan or Heat Recovery Unit in bedroom

[Butterfly44]

My master bedroom has 2 outer walls. It's a Victorian building so no cavity walls. There is an en-suite with an extractor fan. However the bedroom walls and ceiling have been having condensation and mould. I'm trying to increase ventilation to help, though do try and open windows often. So I'm thinking of replacing the en-suite extractor fan to a humidistat one, and wondering how to increase ventilation in the main bedroom. A fan might be noisy? Reading up, a heat recovery unit looks a possibility. Has anyone had one installed, are they quiet enough for a bedroom? Thanks in advance

If you get a decent fan with a trickle setting it should be ok. It does seem worrying you have condensation in summer, perhaps you could get one of those thermometers with the humidity check on to see whether it's very damp in the air?
I assume you have checked the fan and it's actually working and not somehow blowing all the steam back into the room?
We have a trickle fan in our ensuire and bathroom and the bathroom is much less mouldy than before as the tiny constant movement of air is enough to keep the damp off.

modern fans can be extremely quiet. The better ones have a ball-bearing motor and rubber anti-vibration mounts. This may be quite different to the fan fitted by the builder, which may have been selected by price.

mine are as noisy as the sound of wind blowing through treetops. You can't hear them over the sound of a running tap or a filling cistern, or through a closed door. The cost of electricity is negligible.

Does your fan vent straight through the wall, or is there a duct in the ceiling or somewhere? A photo would help.

Also, as JohnD2 mentions, you may need tro run it for longer periods. Showers in particular make a lot of steam, and water evaporating off shower trays or towels will continue to generate damp long after you have left the room.

Thanks @johnd2 @PigletJohn 🙂
The en-suite fan vents straight out the outside wall so no ducts. It's working ok, it's a basic one that stays in for 15 min after. The en-suite isn't so bad, it's the bedroom I'm concerned about. After a shower humidity in the bedroom can go up to the 70s! Mould comes and we wipe it off but it's come to a point I want it 'cured'. So considering repainting bedroom walls with bathroom paint that has fungicide properties and is more sheen for starters....and I thought a fan or heat recovery unit would help for ventilation. There's a lot of price difference between those and whether it has humidistat features.

if the en-suite fan was working correctly, it would draw air through the gap under the door, creating suction that prevented steam drifting into the bedroom.

So either that is not happening, or there is another source of water in the bedroom, such as a leak under the floor or through the wall, or wet towels in the bedroom.

For the extractor to work correctly, the bathroom door and window must be closed so that it can create suction.

Can you post a pic of your bathroom fan please? How long does it run for?

70% humidity is not going to be an issue in summer, is there something making your walls particularly cold or wet from the other side?

@PigletJohn
This is the fan in the en-suite. There is no window, only this to the outside

how big is the round bit? 100mm diameter?

can you see a maker's name or anything?

does it seem irritatingly noisy?

Do you keep the bathroom door shut?

It's an Envirovent silent 100. Yes 100mm fitting. It sounds like a normal fan, not particularly silent when on. I suppose we don't always keep the door closed and can see now that can be an issue.

'mmm, that's quite a good one.

Like this though yours may be an older model.

If working correctly (not clogged with dust, fluff, birds nests) it should be pretty effective. You can try holding a bit of tissue, or a smouldering joss stick or fag, close to the grille to see if it gets sucked. Also close the bathroom door and check for a draught being pulled under it.

They can be taken off for cleaning. I presume the outside grille will be difficult to see, but you might be able to peep through looking for daylight.

As it is very cheap to run, you could try leaving it on permanently for a few days and see if that makes as improvement. As long as you have energy-saving or LED lighting (assuming it turns on with the lightswitch) the cost will be negligible.

There is an adjusting screw under the cover, you can increase the run on time to (I think) 30 mins max. There may be a plastic screwdriver-like tool clipped to the inside casing to fit.

You can wash the outer casing and grill, as it detaches, and use a small soft paintbrush on the propellor (after turning off the electricity) if it is fluffy. IIRC the locking screw to open the case is on the bottom edge.

i'm not keen on the ones with a humidity sensor, they can be slow to start and do not detect odours.

incidentally, I usually like the Soler & Palau fans, which seem to be very high quality but a bit expensive.

it's been pointed out to me that the Envirovent 100 T appears to be exactly identical to this one. Almost as if it was made in the same factory with a different brand name. In which case I think it would be very good. If yours is not "surprisingly quiet" it might be worn out, though the current model has a ball-bearing motor.

@PigletJohn Wow thanks 🙂 You really know you're stuff!!! So maybe the fan is not the problem. You see I had someone round to look at the bedroom and they said it was humidity/lifestyle based and that we needed to increase ventilation by a humidistat fan in place of that one and also a heat recovery unit in the bedroom would help. I later received an email quote of the work which added a few thousand for a damp course. So it left me confused that maybe it wasn't just humidity based, or they just added it...... I feel like I need to find another expert to come round and assess. Here is a pic of what bedroom walls look like if we don't keep cleaning it. Now redecorating completely inc carpet but without increasing ventilation I worry it will come back.

damp course?

did they mean chemical injection?

Was it a company that sells chemical injections masquerading as a damp specialist? Is this a downstairs room?

Whatever the question, chemical injections are unlikely to be the answer.

your later pictures show more damp.

What is on the other side of the walls of that damp corner?

Is this a downstairs room and does it have a concrete floor?

have you got a water meter?

Does your boiler have a pressure gauge?

@PigletJohn
Yes their quote recommended chemical injection and replastering. They seemed like a good company and initial conversations didn't say that...simply that it was increased humidity coming from en-suite and lack of ventilation
The bedroom is a single floor extension. Floor is floorboard timber above a raised void. Above is a GRP flat roof we had done about 12 years ago to replace felt. They are solid outside walls. No water meter and we had a new boiler installed last month.

can you show some pics of the outside walls please

particularly interested in gutters, downpipes, drains, and height of dpc above ground.

@PigletJohn
Sure. So this is the outside of the bedroom in question. There is guttering and one drainpipe to the right. The pics of the inside walls from earlier are actually from the left side. The inside floor height is about a metre up the the garden floor.

Forgot to attach the pic

'mmm so the downpipe is not at the wet corner

but if you look at the outside wall, you can see green algae on that corner at the bottom. it suggests water has been dripping from the gutter for a long time. Show us the gutter end, and round the corner, and the roof detailing, and that corner low down, at the back and the side.

is that a door into the subfloor void? Climb in and look at the damp, and any signs of plumbing, from the inside please.

The void should be ventilated with airbricks on at least two sides to allow a flow of air.

Do any pipes or gutters discharge onto the flat roof from above?

@PigletJohn
Bless you thank you. You've been so super helpful!! I'll call out a roofer to take a look and get on to investigating those things 🙂

An update. The roof and guttering is fine... underneath the room in the basement is definitely damp. I've removed the carpet and underlay which smelt mouldy. Underneath is plywood which is pretty dry now it's breathing. We are putting in a new ceiling with insulation so it's warmer.
Underneath has 3 air bricks. I'm not sure what's needed to cure the damp there. There is no DPC. My dad suggests underpinning, but that's way beyond budget.

Does that corner wall have a damp patch with green algae?

Photos please.

The water must be coming from somewhere.

@Butterfly44

The basement room might be damp if the ground is wet due to, for example, leaking pipe or drain, but it would be very strange for the damp to climb up into your room above. There are a lot of myths about rising damp, but it can't climb far up good, unplastered brickwork that is exposed to the air. Chemical injections are unlikely to help.

If you're sure it's not spilling from the roof, gutter or downpipe, I'd be searching for signs of plumbing, including radiator pipes or garden tap, or an overflow pipe, which may only drip late at night.

Sorry been absent. Here are photos of the underneath. I do think there is something inherent in the whole floor not just this room. I've bought humidity meters for all rooms. Interestingly the middle room which has just been redecorated and is completely empty with no furnishings was showing 80% RH today, and it was a warm dry day. I need to have someone come look at the place, but not someone who is going to recommend expensive unhelpful "solutions". Reading I think I need an independent surveyor. Thanks for taking the time for all advice so far.

Been reading up and I think this damp crawl space under the house is the cause of all our problems. There are contradictory 'curing' methods of a) venting with more air bricks for air flow to b) lining the whole crawl space with a poly membrane and blocking vents.