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.

Insulation worries

Four days of speaking and answering questions at the National Homebuilding & Renovating Show in Birmingham has only strengthened my concerns about the issues relating to the insulation of walls in old buildings. Twelve months ago the subject was barely on most people’s radar but, this year, the volume of questions relating to the topic was staggering and was only equalled by those about damp. Indeed, many of the questions embraced both topics; a fact that in itself is worrying.

I tried to give a broad overview of the subject in my seminar ‘Solving damp and improving energy efficiency in an old home’. The problem is that there’s no easy, one-fits-all solution and we have to question whether wall insulation is a good idea in any solid walled building.

My last post ‘old walls perform better’ highlighted the recent research by the Society for the Protection of Ancient Buildings (SPAB) into the energy performance of old buildings and I’m sure it’s going to be a subject I’ll be writing a lot about in the future. For now it’s worth reiterating some of the key issues about wall insulation.

Importantly, walls can be prevented from breathing and interstitial condensation may occur, resulting in rotten joist ends and general decay. Internal insulation separates the building’s thermal mass from the interior; takes up valuable living space; means features such as dado rails, cornices and so on are lost; while windows are set back due to the thickness of the insulation. If a dry lining system is used there is the added factor that the walls will appear flat and lifeless and the acoustics of the room may become rather ‘sharp’. Adding external insulation to walls is likely to ruin the aesthetics of an old buildings.

Natural ‘breathable’ options for internal wall insulation may include wood fibre, reed board or hemp fibre overlaid with lime plaster but we are still learning and, whatever method is used, great care needs to be taken to avoid potential problems with thermal bridging. An understanding of the way individual buildings work and the accurate detailing of junctions with other elements of the building is vital.

Quite understandably the well meaning owners of thousands of homes – be they of any period from medieval timber frame to Edwardian terrace – want to insulate their walls. At the moment there is still uncertainty about the best way forward and there needs to be further research so that good advice is offered which makes homes more energy efficient without storing up problems for the future.

Image credit: PRP Architects

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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

Listed building allure

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

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

Fire in old buildings

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

Adapting old buildings

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

Building lime knowledge

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

Drain problems

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

Building remembrance

Visiting Blood Swept Lands and Seas of Red, the poppy installation at the Tower of London, reminded me that the built environment frequently plays an important part in both remembrance and memory. Each of the 888,246 ceramic poppies that flood the moat of the Tower depicts a death in the British forces in the First…

Materials testing

Materials testing

New techniques and materials aimed at producing low carbon solutions mean this is an exciting time to be involved with new build and retrofit. There are dangers though, in the rush to innovate there may be failures along the way so it’s vital that there’s scrupulously testing and monitoring at all stages. This is why…

Hidden London

Hidden London

Impending development often means there is a chance to step back in time because archaeological investigation may be undertaken as part of the work. This is especially true in London where layers of history have been laid down by successive generations as the city has evolved. Visiting Barratt London’s Landmark Place site close to the…

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

Listed building allure

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

Fire in old buildings

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

Adapting old buildings

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

Building lime knowledge

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

Drain problems

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

Building remembrance

Visiting Blood Swept Lands and Seas of Red, the poppy installation at the Tower of London, reminded me that the built environment frequently plays an important part in both remembrance and memory. Each of the 888,246 ceramic poppies that flood the moat of the Tower depicts a death in the British forces in the First…

Renovation tale – Part 1

Renovation tale – Part 1

This is the tale of my first major renovation project some years ago… On the table is the surveyor’s report; yellow Post-it notes stick from its pages in such profusion that they no longer have any relevance. Phrases like “needs attention”, “must be thoroughly overhauled” and “a fair amount of dampness” are highlighted by marker… Continue Reading