TECHNICAL SPOTLIGHT: INSULATING STONE BUILDINGS

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Insulating Stone Buildings

As conservation architects with specialist knowledge of traditional buildings, we frequently work on old and listed stone-built structures across Scotland, from rustic barns to castles and mansions. These stone buildings are beautiful and an iconic part of Scottish heritage, which we do everything we can to preserve, but refurbishing them does come with challenges.

One of the main issues is how to insulate them properly. Stone is a material that needs to be able to ‘breathe’, allowing moisture in and out. Conventional insulation and waterproofing materials are not breathable and can trap moisture in the stone. This can lead to moisture building up in the stone over time, eventually causing rot in timbers, compromising insulation and creating a damp, poor quality environment.

A tried and tested solution is to use breathable insulation materials in the correct combination to allow the stone to breathe and release moisture while keeping the interior warm and dry.

In this case study (Splendid B-Listed Mansion Renewal) of a B-listed 18th-century mansion needing extensive renovation, we used a system of insulated plaster and wood fibre insulation. First the insulated plaster is applied to the existing stone. Woodfibre insulation is then installed on top of the insulated plaster, after which a timber frame is added to form a service zone. Plasterboard finishes the wall internally.

[see picture 1 & 2, insulated plaster section, and insulated plaster layers]

[see picture 3 & 4, insulated plaster with frame, and room with existing stone]

[see picture 5 & 6, room with insulated plaster, and room with woodfibre insulation]

[see picture 7, room with timber frame]

This insulation system was designed with the help of WUFI calculations to ensure that there would not be an increasing build-up of moisture levels in the building fabric. When simulating results using other insulation types, they showed that increased moisture would prove a problem 10 years down the line. Improving air tightness, installing masonry-heater wood burners, and using natural materials and low VOC paints were all part of our drive to give a new healthy and sustainable life to this magnificent building and to make it practical and pleasurable for its owners.

In this project, leadwork, chimneys, and roof ventilation all needed careful planning and expert attention. Elimination of horizontal and upward rising damp was needed, and stone repairs involved some external lintel replacements and lime mortar repairs, as well as pointing.

We have also tackled insulation of stonework on many other projects. The most notable of these include a Passivhaus EnerPHit renovation of a barn (Farmhouse Refurbishment), converting it to a warm and cosy home under strict Passivhaus standards and systems.

In another project, on a fine country home overlooking the River Findhorn (Scottish Listed Mansion), issues included addressing damp in rear sections of the house, including in a Victorian gun room. We also updated a separate stone cottage to convert into further accommodation. All areas were vastly improved and updated and also now benefit from more energy-efficient heating systems.

We also used the breathable insulation method on this fantastic estate house on a Scottish island (Scottish Island House), where we worked as Executive Architects, overseeing many technical issues, and a large team working to totally upgrade the estate.

[If you have a Scottish stone building in need of upgrading using longterm sustainable solutions, please do get in touch: Contact

  Find out more about renovating a Scottish island estate, including many areas of stonework, here >>> Scottish Island House - Thomas Robinson Architects

Find out more about Scotland’s greenest renovation project, here >>PRESS: SCOTLANDS GREENEST HOUSE? - Blog - Thomas Robinson Architects

Find out about Tom Robinson’s Saltire Award, which celebrates new houses that improve lives and make Scotland a better place to live, here >>> SALTIRE AWARD WINNERS - Blog - Thomas Robinson Architects

Find out more about preventing damp using sustainable design solutions, here >>> FEATURE: DAMP – HOW TO PREVENT IT USING CLEVER SUSTAINABLE DESIGN - Blog (thomasrobinsonarchitects.co.uk)