The blog

Roger Hunt is an award winning writer and blogger specialising in sustainability, old houses, housebuilding and traditional and modern building materials. He is the co-author of Old House Handbook and the companion volume Old House Eco Handbook.

Old walls perform better

For the past year or so I’ve been following some interesting in-situ research by the Society for the Protection of Ancient Buildings (SPAB) about the energy performance of old buildings. Now the results from the first stage of that research are suggesting that standard U-value calculations, used across the construction industry, underestimate the thermal performance of traditional walls. In some cases, it appears that heat loss through vernacular materials can be up to three times lower than expected.

This is quite a revelation because those accepted theoretical performance figures have long been used as a standard base measurement by professionals and homeowners when old buildings are being up-graded, altered or even assessed for Energy Performance Certificates. Put simply, it looks as though the thermal performance of our buildings has been undersold.

Ultimately, this underselling could have negative consequences for historic buildings as calculated theoretical U-values, which suggest a poorer performance, may lead to disproportionate energy saving interventions being adopted which may not only be unnecessary, but also invasive and potentially harmful to the fabric of a building.

SPAB’s research compares the in-situ U-values of various traditional vernacular walls – including timber, cob, limestone, slate and granite – against the theoretical U-value for these walls using the BuildDesk U 3.4 software. It suggests that 79% of the walls sampled perform better than expected.

Of course, U-values are not the complete story. Energy efficiency is also about occupant behaviour in the building, moisture content in the structure, humidity, temperature, air-tightness, the quality of the air we breathe. Even so, this research is a start in broadening our understanding of how old buildings work and I, for one, will watching the ongoing research with interest.

SPAB audio visual presentation on the project here.

2 Responses to Old walls perform better

  1. Interesting article. I refurbishing my 17c. cottage after removing all the modern extensions including double glazing the old cottage has become much warmer. The cottage is timber frame, wychert, brick, stone and anything else I think they could find at the time!

  2. Stone most defintely retains temperature better than stick building, properly cured concrete retains energy extremely well. Once Thermal Mass is brought up to temperature it is very difficult to change that temperature, therefore it takes little energy to maintain it. A geo-cell consisting of 1,000,000 lbs. of stone aggregate andf item 4 can be used under the slab to store heat energy collected from a series of 10 geothermal wells, with a basement cooling loop(closed system), or outside water source (open system) to cool the structure during the warmer months. The temperature in the earths soil is 55 degrees. A consistent flow of 55 degree water throughout the radiant tubing coils within the thermal mass panels will bring the structure down to temperature, which is always set at 70 degrees; it is the most comfortable temperature to maintain all year round with no expansion or contraction of the structure. Since it is not a forced air heating system where the temperature of the house will change every time the wind howls because cold air is replacing the forced hot air and the boiler system has to continually start up to heat the house. The thermal mass structure will retain it’s 70 degree temperature with minimal energy applied to the system.

    Please check out our blog, we are a startup and just getting the ball rolling.

SPAB Working Party

For the last 25 years conservation experts and volunteer heritage enthusiasts have come together to join the annual Working Party run by the Society for the Protection of Ancient Buildings (SPAB). I went along to join them and created a video about the Working Party at Sullington Manor Farm near Storrington, West Sussex. They were working…

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SPAB Working Party

For the last 25 years conservation experts and volunteer heritage enthusiasts have come together to join the annual Working Party run by the Society for the Protection of Ancient Buildings (SPAB). I went along to join them and created a video about the Working Party at Sullington Manor Farm near Storrington, West Sussex. They were working…

Listed building allure

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Every year, many of the estimated 450,000 listed buildings in the UK change hands on the property market. In England and Wales these properties are designated Grade I, Grade II* or Grade II having being deemed to be of historical, cultural or architectural interest. All buildings built before 1700 Tweet

Environmental Pocketbook

Environmental Pocketbook

If you’re going to invest in just one book on sustainable, low carbon building I’d strongly suggest that you make it The Environmental Design Pocketbook. Now in its second edition, this useful volume by Sofie Pelsmakers should be essential reading for architects, designers, developers, planners, students, clients and anyone else involved in the construction and operation of buildings….

Fire in old buildings

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The devastating fire at the Grade I listed, 18th century National Trust mansion at Clandon Park, Surrey, once again highlights the need to do everything we can to protect old buildings. Whatever the size of the building, there are simple measures that can be taken to reduce the risk of fire, ensure early warning of a…

Adapting old buildings

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The need for fresh air and light in buildings is something I’m often talking and writing about because it’s central to creating a good home, but the theme is nothing new. I was reminded of this when I recently visited the King Edward VII Estate, near Midhurst, West Sussex. Here, the former sanatorium is being…

Building lime knowledge

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Lime, in the form of mortars, renders, plasters and paints, is a key component of old buildings and essential to their repair – or at least it should be. Today lime-based materials are also emerging into the mainstream and being used within low carbon construction systems, employed in everything from homes to superstores. All this…

Drain problems

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A blocked drain is not a pleasant thing to wake up to. What’s worse is the realisation that it’s something that can generally be avoided by doing what I’m always talking about: maintenance. The drainage system is easily forgotten because much of it is hidden away underground but, as with any element of a building, it…

Building remembrance

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