To think our house is making DC sick

Stop having children you can't afford to house suitably.
It is mind boggling that you are bringing another child into a mouldy, overcrowded house! Why are you not working, most people don't give up work until they are due to give birth, especially if they are only working part time to start with.
Obviously your living situation will be negatively affecting your existing child so you and your partner need to be working your arses off to move into more suitable accommodation.

Could you afford to buy a couple of dehumidifiers, around £100-£200. I’d have one running in her bedroom at the very least? Then run them in the high traffic areas. Hopefully in the summer the situation will improve. You need to make sure it’s cleaned daily.

Have you considered a pet allergy?

TBH if it’s the mould causing the issues, nothing will change despite going back and forth to the GP if you can’t contact the landlord. Have you put yourselves on the council house list? This is definitely not a good environment for a newborn baby.

Is this a rented property? Or a family property you are in?

either way speak to your council environmental health housing team. They can come out and inspect, if the landlord needs to do something then they have legal powers to force him to do something to remedy the problem

its condensation damp from these photos you need to ventilate the property. Keep windows open slightly, or use a dehumidifier.

This - specifically the last point. I feel so sorry for your poor children. Absolutely awful to have them living in these conditions.

This isn't good. I lived in a similar situation for 6 months and became very sick with pneumonia. Definitely get a dehumidifier and in summer leave the windows open as much as you can. Others have given good suggestions for treating the mould. Is there any possibility of removing the carpet?

You say you have tried a dehumidifier, but you need to run it at least twice a day for a couple of hours at a time to make a difference.

Get the windows open

Turn the heating up

Declutter

Clean the mould daily

Report the mould to your landlord and get them to check for water ingress (but it is probably caused by condensation).

Take urgent steps to move out.

Do not have more children until you can house them safely.

You need to splash out on a dehumidifier (a good one, like Meaco) and have it running 24/7 in her bedroom.

These are all also chemicals, just to clarify. Everything is made of chemicals. 👍

I know you say you have tried a dehumidifier with no impact but you really need to run it continuously for weeks before you notice any visible effects. You need to monitor the humidity in the room regularly and keep a record.

Open as many windows as you can around the house for at least an hour a day with kitchen and bathroom windows open all the time when you are in the house. You need to get some airflow through the house.

Obviously you are wiping down the mould as soon as it appears, daily if needs be, do not leave it for a few days.

Do not dry clothes in the house if at all possible. If you have no choice, use an airer in a small room with the dehumidifier running over night.

Move as much furniture as you can a foot or so away from the wall.

Contact your landlord or managing agent every time the mould reappears and take time stamped photos. They will probably blame you for creating the mould but you need to show them all the efforts you have made. They should help by removing damp, peeling wall paper or plaster to let the walls dry behind and then redecorating. Wet carpets should be removed as well.

I think you are going to have to make a fuss to get some action and don’t be fobbed off. Have you shown your doctor the photos of the mould? Maybe the health visitor or midwife for your new baby could help?

Absolutely crazy that this is your living situation and you’re adding another baby to it. Get a dehumidifier, make sure there is airflow and clean. Ultimately though you need to work and get out of there.

Try getting a dehumidifier

Can you get a dehumidifier and put it in the room after it's been cleaned.
You can also buy the little moisture absorbers.
I don't use vinegar cos I hate the small but pure clove oil inhibits mould as well
I live in a humid place in NSW so I'm used to cleaning before it gets mouldy.
She won't get better unless you sort it unfortunately.

So what if the house is ‘old’? My house is over 500 years old but we don’t have that. But I maintain the place.

Water’s getting in somewhere.

The air will be carrying many millions of spores. Not good.

OP I am allergic to mold and when I was living in a moldy house I would have constant colds / skin issues - doctors tried all sorts of creams and stuff, which helped but the only thing that fixed it was moving out of the house.

I also had a skin prick test to help confirm what the route cause of the issue was.

Another person who would strongly recommend a dehumidifier. Get a low energy one, at least 12l per day, some have a HEPA filter, Run it continuously for a week or so, then see where you get to in terms of the moisture content in the air. Mould like this in old houses can be caused by condensation due to poor ventilation and colder uninsulated walls. Try it and it should make a huge difference.

You've had five years to get out of this place and now you're having another child?
Okay.
Well, I think your priority needs to be finding suitable housing for you and 2 children, as no-one seems to be listening to your concerns about your 4 year old (and, as yet, unborn child).

I started thinking mold as soon as I read your opening paragraph and then you confirmed it. Holy crap OP that is bad bad bad mold! There are some great Facebook groups I’d recommend looking for but ultimately if she is allergic then she needs to get out of there asap. It’s terrible for newborns too. Can you get on the council list?! Sorry you’re dealing with this. Is the house wet? Can you get a dehumidifier? Are you cracking windows each day for air flow? Cleaning the mold with bleach? Any soft furnishings that get mold have to be thrown out as they can’t be remediated even by mold experts and that is the expert advice. Sorry you’re dealing with this.

I'm sorry to say but most problems with mould are self inflicted.

Have a look at this it might help.

Not a permanent solution, Op, but have you tried removing all furniture (room by room) and scrubbing all wall and ceiling surfaces with sugar soap and hot water, as if preparing for painting? Then wash it with mould killer. Go to a paint distributer. it seems you will have to try to inhibit and control the mould while you live there.
Open the windows more.
Check for roof leaks or where ever moisture could be entering.
Ask landlord to repair any damage. Repaint each wall and ceiling with rollers and paint with added mould inhibitor.
Choose a washable, not totally flat paint that is easier to wash each year.
Hopefully any repairs can be made. Also ask the landlord to install a reverse cycle unit? The aircon. turned to dehumidifier and at 20 - 23 degrees celcius could help.

The carpets, I would remove if full of mould.
Can you obtain seconds, left over carpets from a roll, or second hand carpet in good order? All rooms might be different colour but it will be healthier.

Having lots of animals is problematic - adding to moisture in the air. Can you contain the animals to just one room or the garage?
.

Hmm

Clearly there's something you're not doing something to enable your situation:

Move to a cheaper area
Cut on spending
Work more
Expect less

But do not live in a mouldy house

Lack of ventilation, lack of heating, water ingress, no cavity wall - the cause could be any or several of those. The age of a house has nothing to do with it.

You don't see e.g. old churches being mouldy by default, as long as they are well maintained. If you are a legal tenant, move the furniture a few inches away from the walls, get a dehumidifier, take off the wallpaper (there will be more mould underneath), bleach everything that may be mouldy including furniture. Don't repaint until everything is dry as a bone. That may take weeks or months, I'd wait until the summer.

Once you've taken reasonable steps and it's still coming back, contact the landlord, agency, environmental health, Shelter.

That's not normal. I've lived in lots of old houses. None of them has anything like that.

Do you really want to be in a relationship with someone that won't take your child's health seriously?

@anonhop OP isn't working. I'm pretty sure her partner isn't either.

If you're living with family, I'm going to assume you're paying under £1k/ month in board (otherwise you should be renting yourself!).

If you both work full time on min wage you're bringing home £3,000.

You'll have some costs of course, say £750/ month (generous)

You should've been saving at least £1,250/ month for 5 years, so you should have over £75k saved up which is surely a deposit on a small place?

Now you may be paying less than £1k board or you may be earning more/ less, have childcare etc, but you need to get out of there asap & so you may have to work to make that happen

@PeteReturns I disagree it's a "man" issue. Women are equally as capable of working. This includes pregnant ones with 4 year-olds. I managed it.
If I relied on my husband's salary alone we'd still have no no choice but to live in our mouldy and damp rental but we both worked our arses off on pretty crap wages (and when I was pregnant and then with a baby to child) so we could move to another property (also rented) suitable for our family. By no means a big house, but a mould-free one.