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.

Why old buildings need to breathe

Why old buildings need to breathe

Spending three days talking and lecturing at the National Home Improvement Show made me again realise the huge importance of getting across the message that old buildings need to ‘breathe’. Many people simply don’t understand that using the wrong materials can be an expensive mistake which may wreck their home.

The way old buildings work is incredibly simple and, when I say ‘old’, I’m not just talking about ancient structures but virtually all buildings with solid walls – these include Victorian and Edwardian homes.

What has to be understood is that the modern building techniques that we know today began to be introduced in the second half of the nineteenth century and that cement based mortars, renders and plasters only came into general use by the late 1940s. These techniques rely on impervious outer layers, cavity walls and barriers against moisture – such systems are totally incompatible with traditional solid walls which work in a very different way.

In solid walled, old buildings, the bricks and stones were generally bonded with weak and porous mortars made of lime and sand. Where external walls constructed with these materials, and others such as ‘cob’ (earth), were rendered, lime render was used and this was often limewashed so the structure was able to ‘breathe’. When it rained, moisture was absorbed a few millimetres into the external surface but was able to evaporate when the rain stopped, helped by the drying effects of the sun and wind.

Inside, walls were plastered with lime and finished with simple breathable paints. Any excess internal humidity from washing, cooking and human activity, was dispersed via open flues and draughts, or absorbed by the breathable surfaces. In addition, a kitchen range and open fires burnt from autumn until spring, drawing air through the home and keeping internal surfaces at a steady temperature. Provided the building was maintained, the structure remained essentially dry.

In recent times the understanding of how traditional solid walls work has become confused and builders have tried to apply modern techniques to breathing structures. Cement renders, along with ‘plastic’ paints, waterproof sealants, damp proof membranes and even insulation materials can act as a barrier to the building’s natural ability to breathe. This is where the trouble occurs: the mix of technologies traps water within porous materials and exacerbates the very problems that they are trying to resolve.

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Linoleum naturally

Linoleum naturally

Lino is a bit like Marmite, people either seem to love it or hate it. For some it conjures thoughts of cold and institutional floors and it’s often (wrongly) used to describe vinyl. Unlike vinyl, which is petroleum based, linoleum has outstanding eco credentials and antimicrobial and hypo-allergenic properties. A hard-wearing and almost totally natural product, linoleum…

Research, research, research

Research, research, research

Location, location, location may be the estate agent’s mantra but when you buy an old house research is just as important – it helps you understand what you’re buying and will make a renovation project more successful. What’s more, much of the fun of working on an old property is finding out more about its history…

Water savings

Water savings

Water is a finite and precious resource, we all know that – or at least we should. I was reminded when I visited Bermuda. Here the architecture is influenced by the need to collect rainwater. Stepped and whitewashed roofs are a key feature of many buildings with their wedge-shaped limestone ‘glides’ designed to channel rainwater…

Energy: Nest Thermostat

Energy: Nest Thermostat

Controlling your heating system is one of the quickest and easiest ‘wins’ when it comes to saving energy (and money) in the home and, although I’ve mentioned thermostats here before, I make no apology for writing about them again. In the USA Nest has been a trailblazer both in terms of technology and design. Now the Nest Learning Thermostat is available in…

American Barns

American Barns

by Jan Corey Arnett, Shire Publications The barn is an icon of rural America but how many of us who have driven by these structures and remarked at their bold colour, diversity of style and often ramshackle appearance have any understanding of their origins? Jan Corey Arnett was raised on a Michigan dairy farm and…

Switching on to style

Switching on to style

There’s nothing very sexy about light switches or power sockets. At least this is what I’d thought until I went to a recent launch event for MK’s Elements range of ‘decorative wiring devices’. I came away realising that switches can be cool. What’s more I delved a bit deeper into wireless light switch solutions which…

Repair not restore

Repair not restore

Visiting Coventry to speak at an SPAB Old House Eco Course I was reminded of the complex philosophical issues associated with caring for our built heritage, particularly the value of good new design in an historic environment and the need to understand the fundamental principle of repair rather than restoration. The ruins of Coventry Cathedral…

Insurance and flooding

Insurance and flooding

Flooding is something I’ve already written about but it seemed important to think about the insurance implications relating to old buildings. In this Q & A I’ve asked Amanda Harman, who works as senior client manager of High Value Households at Aon Private Clients, for her views: What are the particular insurance issues relating to…

Responsible retrofit

Responsible retrofit

Retrofit requires an understanding of the building coupled with an holistic approach. This may sound simple but it isn’t, buildings – especially old buildings – are many layered entities and it’s not only the structure that has to be considered, it’s the behaviour of the building’s occupants. When planning retrofit strategies, heritage, technical and energy…

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 markerContinue Reading