Calsitherm Climate Board - A Historic Solution

Historic and heritage buildings require a far more holistic approach to insulating to avoid degradation and damage, necessitating a need to balance energy efficiency with breathability and damp protection whilst most importantly maintaining the characteristics of the building and preserving the facade.

Ecological Building Systems UK believe they have found the perfect internal insulation solution for older buildings with Calsitherm Climate Board to complement their existing range of more natural insulations.

Calsitherm Climate Board is made from calcium silicate, a micro porous mineral building material with effective insulating properties: its high capillary action ensures humidity regulation and the nature of the material means that mould cannot form on its surface.

Niall Crosson, Technical Engineer with Ecological Building Systems UK explains the mechanism in more detail; “The critical point where condensation forms in internally insulated historic buildings is the interface between the insulation and the colder existing brick or stone and thermal bridges. Condensation may settle on the surface of the stone, and over time cause mould growth and other forms of structural deterioration and internal surface damage. We may minimize the risk of vapour penetrating the insulation layer but as there are so many ways by which vapour can penetrate the insulation layer and condense against the existing wall it is important to prioritize an insulating material’s drying or vapour diffusion characteristics as highly as its insulating properties. When we internally insulate historic or old buildings with materials which prevent vapour diffusion this may prevent penetrating moisture from drying out. Rather than allowing condensation and moisture to accumulate between the wall and the insulation, Calsitherm Climate Board absorbs condensed water rapidly at the interface between the wall and the board, stores it within its structure, and allows it to disperse harmlessly to the living space at a later stage.”

Calsitherm Climate Board is a straightforward solution to internal insulation and building restoration. It is installed using special adhesive mortar and can be faced with a lime based plaster for an aesthetic and breathable surface finish. All the system components are available from Ecological Building Systems. Calsitherm Climate Board is non-flammable and is classed as A1.

Niall Crosson concludes; “Insulating older buildings which may be subjected to damp and mould has always proved a challenge. Where the option of externally insulating buildings is not possible internally insulating buildings introduces more challenging conditions and greater risks from a building physics perspective. Calsitherm Climate Board offers solutions to thermal bridging and provides unsurpassed protection against the risks of interstitial condensation, mould and structural degradation. Simply applying 3cm of Calsitherm Climate Board on a 500mm solid stone wall can reduce heat loss by up to 50% without introducing the risk of mould growth and condensation risk. There is little point in achieving exceptionally low U values and increasing the risk of condensation. This is not sustainable either for the homeowner or the building nor is it cost effective in terms of the remedial work which may be required to remedy damage created by mould growth and condensation. We are delighted to be associated with Calsitherm Climate Board, its diffusion open properties fit perfectly with our existing range of building solutions and we believe it provides a unique insulation solution for internally insulating historic and old buildings. It is vital to ensure older buildings breathe and to use insulating materials which are compatible with the existing structure. Calsitherm Climate Board along with the plastering system ensures they can.”