Mould after grant funded insulation?

Mould after grant funded insulation?

8:36 AM, 11th April 2022, About 3 months ago 25

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Hi Everyone, I have a property owned for almost 3 decades. Recently I have had mould appearing on the inside wall below the front ground floor window.

Despite painting over with anti-mould paint the mould keeps reappearing. I have a suspicion that it is connected to the insulation which was done approx 10 years ago. I never had this issue before the insulation was done.

The insulation was done with the labour version of the green new deal ie was grant-funded. I still have the 25-year guarantee for what it’s worth. My understanding is the roof was done but I’m pretty sure the walls too.

Since the works were done it has been rated C (EPC). The current tenants ensure the house is ventilated when drying/washing clothes etc.(which can sometimes cause issues).

The house is a terrace built around 1890ish. Please find attached a picture of the mould (main pic). Hope that helps. I’m at a loss but if you/the readers ask me anything – I would try my best to answer.

My late mum did say mould periodically returned, but it despite the passing of 3 decades it seems to have only become an issue shortly after the insulation.

Any thoughts/ideas/recommendations as to what to do?



Pete England - PaTMa Property Management View Profile

10:33 AM, 13th April 2022, About 2 months ago

Here’s a few links that have help us in the past with damp.

It’s on my Wakelet site.

Fizi247 View Profile

16:33 PM, 13th April 2022, About 2 months ago

Have you considered using the Dutch method of eradicating damp and mould.

I experienced the same problems on my property back on 2006.

Once I implemented the Dutch method of damp control/mould, my problems were resolved.

By all means look to your guarantee on previous works carried out also.

Jessie Jones View Profile

9:14 AM, 16th April 2022, About 2 months ago

From the picture it appears that mould is also growing on the plastic window, which suggests that the issue is one of condensation, not water ingress.
Anything close to the wall, such as long curtains or furniture, reduces air circulation which exacerbates cold pockets, and condensation.
Are your tenants leaving the curtains closed?
Also, some mould preventing paints can make the issue worse. They work by waterproofing the wall underneath in a supposed attempt to stop water from outside coming in. But in doing so they can cause the vapour inside the house to condense onto the wall rather than get absorbed.
My first steps would be to shorten the curtains and remove the water proof paint, replacing it with a breathable paint. It may be easier to remove and replace the existing plaster in that area. This will also give you the chance to inspect the brickwork behind and test it for water content.

Malcolm Ratcliffe

21:47 PM, 23rd April 2022, About 2 months ago

The age of the property suggests solid brick walls. You suggest they might be insulated. Tap the wall beneath the window. If it sounds hollow there might be insulation. If it sounds solid then it could be solid brick. Try to estimate the wall thickness. If it’s 9 inches it’s solid brick.

Now solid brick is a worse insulator than a double glazed window, so more condensation will happen on the wall than the window. Wet surface on the walls equals mould. Look at the mould on the window frames. A cold room, so any moisture will condense on the coldest places … the walls.

In our current home, with solid brick walls, we suffered damp walls when we first moved in 40 years ago. We insulated the walls. We dry clothing inside the house. We don’t ventilate the bathroom much. We don’t have mould because the walls are insulated and so are warm and the moisture doesn’t condense on them.

The electrical wiring looks dodger, clopped to the skirting.

Look at the skirting there is a screw or nail holding it to the wall, you can see the brown rust and stain beneath it. The nail is metal, a good conductor, in a solid brick wall. The head of the screw / nail is colder than the wood. Condensation forms on the coldest places, the metal, it’s often damp and it’s rusting.

Insulation gets rid of many problems, and it reduces energy costs. These are all reasons why government is raising energy standards for rental properties.

Insulation rules OK!

Malcolm Ratcliffe

21:58 PM, 23rd April 2022, About 2 months ago

The whole building contains a certain amount of moisture in the air. This moisture will tend to condense on any cooler surfaces. Now if you add insulation in one part (e.g. above ceilings)then that part becomes warmer, so no condensation there. But then there is even more moisture in the air and it always condenses on the coldest surfaces. So adding insulation in one place could increase condensation elsewhere. It’s basic physics, even the government can’t change that!

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