help........mould/condensation

Check no leak is coming from the roof or guttering. Water could run down the inside of the cavity. If you can get up into the attic, explore the area above where the issue is.

Looks like your driveway is built too high against the wall. Building Regs require 2 bricks below DPC for hard surfaces that water can splash up from. You can get away with one brick providing it isn't too exposed to weather on that side of the house. In your case though, it sounds like half a brick, and then bitumen stuff has been painted on... I guess the bitumen will protect the bricks from splashing, it isn't allowing moisture to escape though at that level. It shouldn't be painted on below DPC especially as those bricks get soaked from ground water and the moisture needs to evaporate away. Regardless of whether the drive height and paint are causing this problem, I would plan to cut a strip of the driveway out alongside the house to expose the bricks below DPC more (I'd put stones in the trench to a lower level than the drive surface), and remove the bitumen paint. Repair any damage to the DPC/pointing. That will all result in a more breathable situation amd hopefully be sufficiently protected from splashing if the trench is wide enough.

Others have already advised about pointing to enhance the wall's weather proofing.

In terms of condensation, that will also be to do with your living habits to some extent - perhaps to a large extent or even entirely. In other words, what is going on inside the home, as opposed to what is coming in from the outside or a leak. We produce loads of moisture in our domestic activities. It isn't that unusual to have mould behind kitchen cupboards. They are cold spots in a room where there is loads of moisture from cooking, and behind the cupboards lacks ventilation. Over the years it builds up. A lot of kitchens aren't heated that well either. Ventilation is extremely important, especially during and after cooking, showering, etc. Open a window. Have trickle vents open. Use fan. Use anti fungal paint behind cupboards. A vent behind the cupboard might not be necessary.

I have a dessicant dehumidifier to bring humidity down when it goes above 60% (@~19C). Those things can really suck moisture out the air and will help dry out damp areas of wall etc. A portable one is best so you can move it around and put it away when not needed. Your attic ventilation system is a more fancy solution so that should be doing the job really, but might depend on how it has been installed. If you have a poorly ventilated loft that is also on the damp side, then the PIR system or whatever it's called might be pulling down humid air from the attic and into the home (again, depends how it has been installed and where it draws its air from).
 
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Check no leak is coming from the roof or guttering. Water could run down the inside of the cavity. If you can get up into the attic, explore the area above where the issue is.

Looks like your driveway is built too high against the wall. Building Regs require 2 bricks below DPC for hard surfaces that water can splash up from. You can get away with one brick providing it isn't too exposed to weather on that side of the house. In your case though, it sounds like half a brick, and then bitumen stuff has been painted on... I guess the bitumen will protect the bricks from splashing, it isn't allowing moisture to escape though at that level. It shouldn't be painted on below DPC especially as those bricks get soaked from ground water and the moisture needs to evaporate away. Regardless of whether the drive height and paint are causing this problem, I would plan to cut a strip of the driveway out alongside the house to expose the bricks below DPC more (I'd put stones in the trench to a lower level than the drive surface), and remove the bitumen paint. Repair any damage to the DPC/pointing. That will all result in a more breathable situation amd hopefully be sufficiently protected from splashing if the trench is wide enough.

Others have already advised about pointing to enhance the wall's weather proofing.

In terms of condensation, that will also be to do with your living habits to some extent - perhaps to a large extent or even entirely. In other words, what is going on inside the home, as opposed to what is coming in from the outside or a leak. We produce loads of moisture in our domestic activities. It isn't that unusual to have mould behind kitchen cupboards. They are cold spots in a room where there is loads of moisture from cooking, and behind the cupboards lacks ventilation. Over the years it builds up. A lot of kitchens aren't heated that well either. Ventilation is extremely important, especially during and after cooking, showering, etc. Open a window. Have trickle vents open. Use fan. Use anti fungal paint behind cupboards. A vent behind the cupboard might not be necessary.

I have a dessicant dehumidifier to bring humidity down when it goes above 60% (@~19C). Those things can really suck moisture out the air and will help dry out damp areas of wall etc. A portable one is best so you can move it around and put it away when not needed. Your attic ventilation system is a more fancy solution so that should be doing the job really, but might depend on how it has been installed. If you have a poorly ventilated loft that is also on the damp side, then the PIR system or whatever it's called might be pulling down humid air from the attic and into the home (again, depends how it has been installed and where it draws its air from).

I think the PIV in the loft space is been hindered by clogged filters.
I had some work done up there that produced an insane amount of dust about a year back.
Id intended to leave the dust to settle and then change the filter, but never got roound to changing it. (My bad)

Ill get some ordered and crank it up so its working double time and see if this reduces the humidity behind the unit which is currently at 92%.

We do open windows and use the fan when cooking, and we stopped drying clothes on the radiator a few years back.
When i bought the house, the old owner was obsessed with insulating the property and basically sealed up any points of ventilation.

The kitchen is quite an isolated case as other then the window been open there isnt any place for the moisture to escape without running the fan.

This been said, the battle for 'normal' RH levels will be long.

My plan is to take the current kitchen unit out and sit a dehumidifier in front of the wall for a time to help dry out the walls.

If sorting the PIV unit reduces the humidity levels behind there then great.
Ill start to address the external issues (if these are a compouding factor to the mould)

Would it be an idea to install an extractor fan behind there that is triggered by high humidity?
Or is this over kill
 
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installed this sensor behind the unit mid week.

My plan is to install the new filters on the PIV in the loft, and crank it up a bit.
See if the affects the humidity behind there.
Failing that it looks like a vent or an extraction unit to the outside.

Both of the last two people who came to look at the brickwork suggested also a vent brick into the cavity on the corner too.

What effect would this have?
 

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