Straw-clay Board – Historic Buildings Insulating

straw-clay board - historic building insulation


Prefabricated construction board, made of straw and clay. Can be applicable as a ready-made background for dry structure, a skeleton wall housing or an internal thermo-insulating material for wooden and brick walls (double-sided variant). Single or double-covered with clay on top of a jute net, finished with a 55 mm rim. It features low weight and good thermal and acoustic insulation.

Insulating historical buildings with breathable straw-clay boards.

Historic building insulation presents unique challenges due to the need to preserve the building’s architectural integrity while improving energy efficiency. The insulation of such buildings must be done with great care to avoid damaging historic materials and to maintain the building’s historical significance. Here’s an overview of considerations and methods involved in insulating historic buildings:


Considerations for Insulating Historic Buildings

Preservation of Character: Any insulation strategy must preserve the building’s historic character, features, finishes, and construction techniques.

Breathability: Historic buildings were often designed to “breathe,” allowing moisture to evaporate naturally. Insulation materials and methods must not trap moisture, which could lead to deterioration of the building fabric.

Reversibility: Ideally, any changes made to a historic building should be reversible, so future preservationists can restore the original conditions without much trouble.

Compatibility: Materials used for insulation should be compatible with the existing building materials to prevent chemical reactions or physical damage.

Regulations: There may be strict regulations and guidelines governing what can and cannot be done in terms of insulating historic buildings, particularly those that are formally listed or protected.


Methods of Insulating Historic Buildings

  1. Roof and Attic Insulation: This is often the most straightforward place to add insulation as it typically does not interfere with the building’s aesthetics. Materials like mineral wool, cellulose, or special foams that allow for breathability are commonly used.
  2. Wall Insulation: This can be more challenging due to potential damage when installing insulation. Options include blown-in cellulose or foam, which can be inserted into wall cavities through small holes that are later patched. The latest technology includes straw-clay boards that can be installed on the inside of a wall.
  3. Floor Insulation: Insulation may be added beneath floorboards or from a crawl space or basement. Care must be taken to ensure adequate ventilation to prevent moisture build-up.
  4. Window Treatments: Historic windows can be very inefficient. Instead of replacing them, secondary glazing can be installed, or specialized window films can be used to improve thermal performance without altering the appearance.
  5. Draught-Proofing: Sealing gaps around doors, windows, and other areas to prevent air leaks can significantly improve energy efficiency without impacting the building’s fabric.


Specialized Techniques and Materials

  • Straw-Clay Boards: These can be applied to walls and are compatible with many traditional building materials.
  • Aerogel Insulation: This is a highly efficient insulation material that can sometimes be used in thin layers to provide high levels of insulation without much bulk. The downside of aerogel is it’s price.
  • Thermal Wallpaper: This is a wallpaper with insulative properties that can sometimes be used in historic buildings.



  • Cost: Insulating historic buildings can be expensive due to the specialized materials and techniques required.
  • Expertise: It requires the skill of professionals who are experienced in both preservation and energy retrofitting.



Insulating historic buildings is a delicate balance between preserving the past and embracing the future. With the right approach, it is possible to achieve energy efficiency improvements while maintaining the historical integrity of the building. Careful assessment, planning, and execution using appropriate materials and methods are crucial to the successful insulation of historic buildings.