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Project: Tyland Barn Wall Insulation



When Kent Wildlife Trust needed new offices, it was only appropriate that this organisation, committed to protecting and preserving the natural environment, should chose to refurbish historic C17th Tyland Barn. No simple task, since the listed building was in a state of almost total dereliction.

The Requirement

To resurrect the old building meant finding an approach that would make it not only structurally sound once again, and effective as modern-day office space, but which would also meet the stringent requirements of local conservation officers, intent on preserving its local character.

The Problem

  • Besides dealing with structural issues, any renovation had to take into account the multiple construction methods used in the original building - brick for the ground floor walls, with timber frame, lathe and plaster render above.
  • The works had to be carried out sympathetically, to remain in keeping with other traditional architecture in the local area.
  • To keep the building's historic integrity, no synthetic materials or systems could be used in the renovation.
  • Given that existing, traditional materials would still be part of the building's structure, these had to be allowed to breathe, or trapped moisture could severely damage their integrity.

The Solution

Lime Green's Warmshell insulation system is able to bring an old building constructed of traditional hardwood timber frame up to modern energy efficiency standards, and to do so sustainably.

For the Warmshell wall insulation system at Tyland Barn, wood-fibre insulation boards were fixed directly to the brickwork on the ground floor and to the oak frame on the storey above, using specialist fixings. To these wood-fibre insulation boards, a base coat of lime render (Prepbond WP) with an embedded glass fibre mesh was first applied, followed by a final top coat (Finish WP).

The Benefits

  • The Warmshell insulation system ensures minimal air leakage, creating a comfortable working environment that is also energy efficient, even when starting with an old building like Tyland Barn.
  • The first coat of lime plaster is specifically designed to adhere to the wood-fibre insulation boards, while the glass fibre mesh within it not only offers impact resistance, but also binds individual boards together into one tight unit.
  • The top coat of Finish WP contains a powerful water repellent that enables water vapour to escape from beneath, but prevents water droplets from entering other than at the most superficial level from the outside. This makes the surface coat almost as waterproof as concrete, but much more breathable.
  • Lime can accommodate a great deal of movement, an important consideration when dealing with a building made from natural materials.


Lime Green's Warmshell wall insulation system has BBA approval and robust European technical approval. The testing effectively exposes the wall insulation system to 25 years of weather conditions in just 28 days, making the testing protocols used severe.


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