Sustainably retrofitting a North London apartment

“We eliminated persistent damp and extreme mould using sustainable solutions – that was the key to the success of our retrofit project,” says Christian Brailey, an experienced architect and owner of a newly-retrofitted North London apartment.


In July 2020, Christian Brailey began a project to refurbish and extend a traditional Edwardian property in North London, which was split into four apartments.

For Christian and his partner, Faye, a landscape designer, using sustainable and healthy materials, which would remedy and prevent the existing damp problem within the property, was key.

Resolving and preventing extreme damp

 Christian explained:

 “The condition of the existing building was very poor.

After years of water damage, the ceiling of the existing infill bathroom was black with mould. The property had very little ventilation, the windows were all single glazed, and the whole interior was generally damp. Overcoming these issues was the biggest challenge for us.

The property is also terraced, which meant we needed to improve the thermal performance of the building from the inside.

Insulating from the inside


After looking for sustainable products that would bond well with the existing building materials and address the range of issues within the apartment, we came across Lime Green.

 Lime Green offered healthy and natural products, which could be used in a variety of applications and solve multiple issues at once. To insulate the internal boundary walls and ceilings, we selected Lime Green’s Warmshell solution – an internal insulation system, comprising board adhesive, woodfibre boards and a coat of breathable plaster.

 To finish the walls and ceilings, we chose Solo, a one-coat lime plaster. Finally, to protect the bathroom from water damage, we used Silic8 Silguard, a breathable water repellent.


Instead of rendering directly onto the woodfibre boards, we used plasterboard between to enhance the building’s thermal, fire and noise performance further. The Solo plaster then created an airtight layer on top.

One particular brick wall was bowed, so it needed additional support. The Warmshell system, along with some wooden batons, offered that support.

The Warmshell system helped us to resolve a variety of issues. It’s an internal system, so we could use it to insulate the property from the inside as the external insulation route was not possible due to being located within a Conservation Area. It improved the breathability too and is great at reducing outdoor noise.

As the materials in the system are natural, they ring true to how the building was originally designed and constructed.

The results

We’re delighted with the results. Visually, the lime plaster looks great. It has a traditional off-white colour, which can be difficult to find nowadays. The whole system has created a natural and calm space.

The natural materials in combination with the mechanical ventilation system has created a really clean indoor air quality, which is so important in London especially.

The acoustic separation is a benefit too – we can barely hear any outside noise.

The thermal performance of the Warmshell system is brilliant. It’s great for managing temperature shift, as it holds heat and releases it when temperatures drop overnight, which is exactly how a building should operate.

I already have two or three other projects where we’re using the Warmshell system and Solo plaster.

The Lime Green team is helpful and extremely knowledgeable and very easy to get hold of.

I would absolutely recommend Lime Green and its products.”

“It’s been great to work with Christian to develop a sustainable solution for the property’s challenges,” says Simon Ayres, co-founder and managing director, Lime Green Products Ltd. We’re so pleased the solution has improved the internal environment so drastically, and we’re sure it will continue to for years to come.”

All images courtesy of Christian Brailey.


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