Damp, cold and mould: Can these increasing problems for living comfort and respiratory health be reliably solved?

By 30/09/2020Latest News
Damp, cold and mould

A case study from an East London tower block

In the Covid-19 era, the nation’s focus on respiratory health has never been greater, and the public is now starting to show concern of the clear link between domestic living conditions and the respiratory system. The NHS officially acknowledges that “if you have damp and mould in your home you’re more likely to have respiratory infections, allergies or asthma. Damp and mould can also affect the immune system.”

So what practical, affordable and effective solutions are there to these problems, especially in the social housing sector and among fuel poverty sufferers?

Steve Buck, maintenance manager at social housing provider East End Homes, tells us how he successfully combatted cold, mould and condensation problems in a 1960s London tower block.


Shearsmith House in Tower Hamlets, managed by social housing provider East End Homes

1960’s solid concrete superstructure with partial brick skin

1960’s solid concrete superstructure with partial brick skin

The Problem

Damp issues at Shearsmith House

For the last two years, trained electrical engineer Steve has been managing maintenance projects across East End Homes’ estate of social housing in the Tower Hamlets area of London. East End Homes are a community-led social housing provider, with over 3800 homes, and a vision to regenerate its estate to bring about a sustained improvement in the quality of life for residents.

Steve is very familiar with Shearsmith House, a 26-storey, 107-flat towerblock, constructed in the late 1960s of a solid concrete superstructure with a partial brick skin. The block has suffered from ever-increasing damp, mould and condensation problems as the years have gone by, and this has culminated with the present situation where Steve reports that “at least 80% are suffering from mould and condensation and it only gets worse the higher up the block you go. The problem is mainly on the outside skin walls at ceiling and skirting board level where airflow is low, and in the window reveals which can get very cold overnight.”

Steve believes there are several factors which have contributed to the damp problems increasing over the years. Poorly conceived past retro-fit projects, including plastic double glazed windows and unreliable modern fans in the four central building extract ducts, have made the problem worse, not better. Added to this is the changing demographic of the residents, with typically more people living in each flat, creating more moisture through increased cooking and washing activities, coupled with a reluctance to open the windows when they do so.

In particular, one resident of a single-bed flat on the fourth floor regularly complained several times a month to the estate management board of cold and black spot mould, that her “walls were sweating”, that her clothes and furniture were becoming so damp that several items had to be thrown out.

Black mould is rife in the flats at Shearsmith, but especially at ceiling and floor level and around the window reveals

Mould and damp make for unhealthy living conditions and can lead to respiratory illness

The most severe patch of black spot mould, just before the remedial work began

The Solution

A dual-pronged attack

Steve took up the project and decided on a “dual-pronged attack”: first address ventilation, and if that did not solve the problem, move on to treating the walls.

He installed new fans in the kitchen and bathroom, cleaned out the ductwork connecting to the central building ventilation system and renewed the air duct valve. Finally, he added trickle vents to the windows.

An air movement survey confirmed that ventilation to the flat now should have been more than adequate. But still, the damp was present and the extent of the black mould continued to increase. So Steve looked for suitable thermal wall treatments to increase the temperature of the internal walls but which wouldn’t create other knock-on problems. He ruled out traditional Internal Wall Insulation (IWI) solutions as the room size would have been reduced to an unacceptable degree in such small flats (IWI solutions being typically at least 100mm deep).

Finally, traditional IWI also left the possibility of air gaps and cold bridges being left at the fixing points, seams and returns, leaving damp problems to recur, both on the surface and in interstitial layers. Steve has seen this problem dramatically at Shearsmith House already in the bigger top-floor penthouses, where polystyrene insulation slabs skimmed over with plaster were installed, and where the damp and mould has penetrated back through and, in Steve’s words, can now only be described as “horrendous”.

Analysis of the failed retro-fitted polystyrene IWI in the Shearsmith penthouses

Spray and skim treatment

Steve’s final choice for the wall treatment – Corksol sprayed cork granules with a plaster overskim – seemed to have the potential to resolve all these dilemmas. The solution is only 8mm thick in total, meaning that the room size would be barely affected and the repositioning of fittings would not be needed. The solution gives a powerful thermal insulating performance for its slim size, and it eliminates any fears of cold bridging or air gaps, as it is sprayed on in a single seamless layer, including round window reveals and returns. Another key benefit of Corksol is that the material is highly breathable (vapour-open) meaning that any residual dampness in the walls can transpire away harmlessly over time.

The granular Corksol layer, spray-applied seamlessly including round the window reveal, ready to accept the final plaster skim

The Good Plastering Company apply the final plaster skim, leaving the room size only 8mm smaller

The Long Term Impact

An affordable, effective solution

Corksol’s local approved applicator in East London, Pete Lydon of The Good Plastering Company, carried out the work in four stages over two days. First, clean down the mouldy walls with a specialist bleach wash. Then spray apply two coats of fine-grain Corksol, each coat 3mm deep, ensuring an even and continuous coverage. Finally, the wall was given a standard 2mm skim of plaster, giving an 8mm overall depth.

In the 12 months since the project was completed, the tenant continues to be very happy with the solution. The days of the weekly complaints are long gone. The flat has remained totally clear of damp, condensation and mould; internal temperature is warmer and more stable; heating bills are reduced and the overall position means that living comfort is very significantly improved for the tenants.

Multiple benefits for landlords and tenants

For Steve, his “dual-pronged attack” has brought three-fold benefits. Not only have the complaints melted away, but he has helped deliver his organisation’s vision by bringing about a “sustained improvement in the quality of life for residents”, and he also knows that the chances of Covid-related respiratory complications have now been significantly contained.

Now, with the confidence of a knowledge they have a solution which works reliably across all four seasons, Steve and his team are planning to fit the same system in many of the other flats in Shearsmith House, starting with ripping out the failed polystyrene in those “horrendous” penthouses!

Need help with a damp problem

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Jamie Orr

Author Jamie Orr

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Join the discussion 2 Comments

  • Catherine walker says:

    Sounds thourough and brave. Corksol brilliant idea. Steve sounds dedicated and determined ! Cork slabs Used on repairing a wall of mine in France and really admirable

  • Jamie Orr says:

    Thank you for your comment. This case study is now over two year old and mould has never returned to the property. Cork moves the dew point in the wall stopping any condensation forming which ultimately causes black spot mould. Also skimming over the product you don’t even know its there!!

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