Smelly house - mould/mildew? Would Envirovent help?

[turningpoint]

Hi everyone, we have a mid century bungalow that is difficult to air enough. It smells bad, we really notice when we come home. Musty/damp smell. It seems to have got worse over a few years. We are careful not to leave wet clothes airing without a dehumidifier and open the kitchen door when cooking. We get some mould on outside walls sometimes (so have moved any furniture away), and lots of condensation on windows in the winter (which we wipe off then open windows). We don't heat it as much as we'd like due to cost and environmental impact. So the house is often pretty cold. If we open several windows wide for a few hours it smells fresher, but the smell comes back soon after closing them.

Trying to figure out what to do about the smell. The roof and gutters have been checked recently. We had one roof leak at one point but a surveyor has confirmed it is all dried up now (used a damp meter on the ceiling). I suppose there could be a leak somewhere else like under the floors (mostly carpeted), or maybe rain gets into the crawl space via vents (would that make the whole house stink?). DH says it didn't seem wet anywhere last time he went into the crawl space. There is insulation beneath the floors.

Any suggestions on A) finding out definitively if there is any kind of leak in the house; and B) whether something like EnviroVent/other mechanical ventilation with heat recovery would be a good solution for freshening the air and removing any mould issue. (I've read a few threads on the latter on here and people seem pleased with it, but would like to rule out any other source of the smell other than just a cold house with unchanged air).

Many thanks!

Following with internet.
I'm wondering if it would be cheaper and more effective to open a small window and heat the place properly than the cost of installing heated mechanical ventilation and the cost of running that?

Yeah good question. I haven't checked the cost of installing and running proper mechanical ventilation yet. But even during cold spells when we have the heating on a lot, we would need a few windows wide open to get a good change of air and freshen the smell. Which means the house is too cold even with heating on.

I've seen from friends that new builds have mechanical ventilation running all the time so wondered if it was now considered a better way of doing things.

Apparently all houses leak air, so you could consider a constantly running extract in your bathroom, toilet and kitchen (all the areas that generally are 'wet') and air will be drawn in from under doors etc.
Constantly running fans can be quiet and low voltage abd so don't cost a lot to run. As your in a bungalow it should be relatively easy to do all this work from the loft.
If you want a definitive answer you should be looking for @pigletjohn

Have you smelled the carpets? They could be the issue. I think I would try that and replace with hard floors myself (checking for leaks when you take them up). Ditto any other soft furnishings. I think you can also get a sort of electronic damp detector as well. I would definitely try to work out the source of the issue before getting equipment etc.

Leave all the windows and doors closed on a cold night.

Does one room have particularly misty windows in the morning?

Which windows do you open each morning, and for how long?

Do you have an extractor fan in the bathroom, and a cooker hood in the kitchen?

Feel all the floors for damp. Especially any room with pipes, like the kitchen and bathroom , and under each radiator.

@Heronwatcher I have smelled the main carpet areas but couldn't smell anything on them. I recently tried cleaning them with bicarb too. It seems to be the air. Replacing the relatively new carpets with hard floors would be more expensive than ventilation.

Maybe getting a damp meter would be a good idea.

@pigletjohn we always have the windows closed at night as it's a bungalow (for security reasons). Never gets too warm. there is usually just more condensation on the bedroom windows which makes sense as we are breathing in there all night. We open bedroom windows, kitchen, bathroom. Sometimes for fifteen minutes, sometimes for a few hours if it's warm enough. The kitchen door is always wide open if cooking with the internal doors closed.

We have an extractor fan in the bathroom and were told opening the kitchen door wide was as good as a fan would be in there.

Will have a go at carefully feeling the carpets for any damp.

I do think the smell gets worse after heavy rain, but don't see how the rain could be getting in. Maybe a rainy day just increases humidity throughout.

Thanks

it does seem to me like you have an undiscovered water ingress problem and an expensive technical solution will not repair it.

An extractor fan in the bathroom, and a hood in the kitche, are actually more efficient as they remove water vapour at source, and do nor rely on wind direction. An open door or window sometimes blows the steam into the house. A modern extractor fan can be very quiet and can run for 100 hours on one kWh of electricity. If you have steamy showers, you need an extra-powerful one with a run-on timer, preferably in the loft with a duct through the ceiling as they are quite big.

A bathroom with an good extractot can also be used if you are obliged to air wet washing indoors, as it will extract the water vapour. Washing draped indoors is a terrible source of damp and also encourages mould which smells fusty.

if you have bay windows, have a look at their little roofs. Look at all gutters and downpipes, and the drains they run into. Look for any signs of cracked, broken, sunk or repaired paving or ground near drains which indicates leaks that have washed away the soil. Look for any slopes or paving that cause rain to collect or run towards the house, and any paving or flowerbeds that are higher than the DPC.

if you can't identify a particular room as being damper than the others, yes, it could be water under the floor. Do you have a water meter?

Do you by any chance have replacement plastic windows with no trickle vents?

now that the weather is warming and your heating will be off, you can open the loft hatch. Water vapour is lighter than air so it will rise up and escape through the eaves gaps (you should be able to see daylight at the eaves, not blocked with insulation) though this would be wasteful when you have the heating on.

There a reason why modern houses have to have trickle vents in the windows. If you can’t find a source of the smell, and it may be under the floor, try and address the background ventilation in all rooms.

Thanks for taking the time to comment!

Update primarily for @pigletjohn: we had an extractor put in the shower room which we were told was a good, strong one. But it doesn't clear out the moisture fully so we often air that room as well (with a draft blowing through it). We got advice and quotes from several electricians before doing it. But if it's not good enough how do you determine which fan to get? It runs through the eaves not fully through the loft.

I have felt the carpets near radiators especially and can't find any damp areas (and the heating had just been on for a couple of hours).

One issue we are aware of is that the house is on a slope so on one side the ground is only just below the crawl space vents. They aren't blocked at all though. It has been like that for decades (presumably since the house was built) and would be a massive job to change the ground level (flower beds, gravel path, one corner of patio, which is sloped away). DH just checked the crawl space again. It is a dirt/compressed rubble type floor and the whole space seems damp he says. No visible wet patches at the moment just musty and damp. But there is one area where some sort of cable comes in low down that looks like it might get water coming in around it, as there is evidence of a possible pool of water having been on the ground there. So when it rains again we will check that again. There aren't any areas outside where water pools. Not sure what to do about the whole space just seeming a bit damp though, the vents seem clear. I suppose we could leave the crawl space hatch open sometimes when airing the whole house.

The drains outside are on the side lower than the house so that should be ok.

No water meter as in Scotland, it's just combined with the council tax cost.

Some of the trickle vents were closed so they are all open now.

We have opened the loft hatch for today. We can't see daylight round the edges but there does seem to be a gap between the edge of insulation and the eaves. There are some old insulation boards on the bottom of the roof inside too which might explain that.

Thanks again!

Also now I think about it, there are of course some drains on both sides of the house. Not sure how the drains connect!

can you post a photo of your bathroom extractor please

include the external vent, and its duct, if any.

if you photograph the eaves (inside and out I can see if you have a soffit or something.

As it is damp under the floor, look at your airbricks. They need to be on at least two sides of the house to get a throughflow, and not blocked with soil, cobwebs, vegetation, extensions, paving etc. As you are on a slope it's posible water is running down towards the house. Often this can be cured by digging a flowerbed or French Drain to catch the water before it reaches the house.

is the wet patch near a drain, downpipe or manhole?

have you got a water meter?

p.s.

modern practice is to have lots of airbricks to keep the void dry. One every two metres along outside walls is not too many. it is, luckily, very easy for a competent builder experienced in brickwork to fit them, especially if you are on a slope with a roomy crawlspace and access.

if there is any rubbish, especially organic matter such as timber, or roots, clear it out. if you are lucky there will be a sack of sovereigns. Builders often hide rubbish under the floor and it can hold damp, especially plaster waste.

I just wrote a reply and added pictures but it didn't post. So I'll write the reply first then add pictures after.

I've taken pictures of inside and outside bathroom fan.

Yes we have a soffit.

Air bricks are about every 2-3m all around. Not blocked but could be cleaned for cobwebs at least.

Rainwater doesn't run down despite the house being on a slope overall as the ground is levelled and tiered. The higher side has a flat gravel area then a narrow bed.

No water meter.

But it does look like the crawl space leak is level with a downpipe which is next to an air brick. See picture. I guess we need to look here both inside and out when it next rains.

We previously cleared rubbish out of the crawl space.

Thanks so much!

Ah it won't let me post photos. I'm not a new member, I name changed for this.

So to describe the bathroom fan, it says airflow icon. Delayed shutter opening. There is a square grill in the soffit to vent it.

The downpipe (running down from the gutter) near the vent outside at the level of the possible leak is closed in at the bottom and goes into a sort of circle of metal. It's not one of the ones that goes into a drain with a grill. But looking at it closely there are two cracks on the sides of the metal circle. And it seems to have had a layer of concrete put on the top of the metal (so maybe a previous repair?). This metal circle and the ground are a brick lower than the air brick though, so I don't see how water would go up through the air brick. Seems more likely it might seep through the wall if there is a leak under the downpipe?

Would this kind of occasional leak into the crawl space when it rains make the whole house musty?

The thing at the base of the downpipe is probably ceramic not metal...

Something I see a lot in my job is houses that have original suspended floors and then extensions where there is a solid floor. The builders should duct the sub-floor ventilation to the outside of the extension, but overlook it. This could cause issues.

@artvandalay I can see how that could cause problems. No extension here thankfully.

I am now thinking that the ceramic bit I can see under the downpipe may continue through the soil and be/be attached to a clay pipe of some sort. So if that is cracked it will be seeping water into the soil and maybe through the house wall below ground. Still not sure if that could cause the whole house to be so musty...

We had a similar dampy musty smell in our downstairs bathroom, turned out the walls beneath the faux marble plastic wall coverings hadn’t been damped proofed and had no ventilation. When we stripped the plastic fake walls off, the real walls below were dripping in condensation! We’ve now brought it back to the breeze blocks and we’re adding damp proof paint and insulation and a vent.

Could it be anything similar for you?

the clay bend or gulley at the bottom of a downpipe or soilpipe is in my experience always cracked or broken in older houses. If yours is around 1950 it might not be. Dig around the bottom of the pipe and look for a cavity, mud, or red worms. If it is a soil pipe you might find wild tomato plants.

a gardening trowel is enough to investigate. If there is concrete round it, look for signs of sinking, cracking or patching. Attempts to patch broken pipes are very common, but always futile.

the Airflow Icon is a premium priced fan, but not very powerful. If you have the common 100mm/4 inch one, it extracts a nominal 67 cu.m/hr

4" fans are mostly rated around 80cu.m/hr; some up to 100. They are adequate for a WC or even a room with a bath, in warm weather, but not powerful enough for steamy showers.

You can get a ducted fan with two or three times the power, but they are bigger and usually mounted in the loft or sometimes hidden inside an airing cupboard or something. These are good for showers. You can get a bigger wall fan, but it needs a bigger hole in the brickwork.

Hi again,

I'll have a dig around at the bottom of the downpipe (it's just one from the roof gutters, not a soil pipe). House is sixties.

I think that fan was recommended since the shower room is tiny, a converted cupboard. But maybe we need to consider getting a better one.

Do you think either or both of these issues (leaking into crawl space somehow when it rains, and not a powerful enough fan above the shower) would explain the whole house being musty?

Thanks!

reading again,

"there are two cracks on the sides of the metal circle. And it seems to have had a layer of concrete put on the top of the metal (so maybe a previous repair?). "

sounds like a broken glazed clay socket with a futile repair. Is it shiny brown? Like a teapot?

very probably needs digging out and replacing with new. Not a complex job for a builder or a burly woman. Quite a nice job in warm sunny weather.

You dig a bigger hole than the socket or gulley, because very often there is a break where it connects to the next piece. The leak washes the ground away, and the clay gully or bend (which is very heavy) sinks into it.

modern replacements are plastic. You can get a replacement collar to put on the next pipe if the collar is broken (will need skilled cutting with a diamond saw)

@dalalteleid the shower room is fully tiled so I don't think that's the problem but thanks for the suggestion!

@pigletjohn yes it's about 18cm diameter and brown glazed looking. So it looks like that needs replacing.