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OLD HOUSE
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CARE AND
REPAIR FOR
OLD HOUSES

  

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OLDHOUSE.INFO WAS FOUNDED IN 2002 BY CONSERVATIONISTS TO PROVIDE INFORMATION ON OLD HOUSE CARE IN THE UK - BASED UPON REAL PRACTICAL EXPERIENCE WITH BUILDINGS. THE SITE IS NOT SUPPORTED BY ADVERTISING OR EXTERNAL FUNDING. IF YOU WOULD LIKE TO SUPPORT US, WE DON'T HAVE A DONATE BUTTON BUT WE DO HAVE PAY-FOR ARTICLES DELIVERED BY EMAIL WHICH YOU CAN BUY HERE.

 

www.oldhouse.info
INSULATING OLD HOUSES
& COTTAGES
and energy conservation

 

 

Householders want to save on expensive fuel; governments and our consciences are encouraging us to reduce ‘greenhouse gas’ emissions to benefit the environment. As a result there is a lot of pressure to cut domestic energy use and in particular to increase home insulation.  

Applying insulation to a building alters the way it behaves. It is like the house wearing more clothes - and many current building insulation measures work in the same way as a warm coat, trapping pockets of warmed air, stopping it from drifting away and taking our hard-earned warmth. But there are clothes and clothes: you can understand that a nice fluffy pullover is one thing, but your house wouldn't want to be permanently trussed up in the equivalent of a wetsuit

New houses have been built with increasing amounts of roof and wall insulation for decades. But old houses (unless they are already built from something naturally insulating, like a thick-walled cottage with a thatched roof) would have to have extra insulation applied in some way to existing surfaces; this is intended to alter the environment within the building.  

Altering the environment within the building can be fairly predictable if designing a new house from scratch. All the technical factors affecting it (which include the balance between insulation, damp, ventilation, materials, vapour-permeability, condensation, heating) can be predicted in the design and building processes and controlled using modern building technology, calculation and the application of regulations.  

But an old house is already there, containing everything (known and unknown) that will interact with any new insulation: the opportunities to balance the whole are limited. Applying insulation can easily unbalance the way the fabric deals with damp, for example. If insulation is installed without understanding what will happen to damp afterwards, the danger is that damp could be retained when it was vented previously, perhaps retained within the new insulation (reducing its usefulness), perhaps held inside the building fabric (nourishing decay). Trapped damp is just as unwelcome for a house as a few days in that wetsuit would be for us.

Which is why we think that if additional insulation is identified as a worthwhile energy-saving measure on all or part of an existing building, then it needs to be pursued with care: it is foolhardy to apply insulation to an old house as if it were a modern house. Our usual guidance when alterations to an old house are being considered is for specific on-site conservation-accredited professional advice - simply because every old house is different and will react differently.

Unfortunately it is easy to foresee that, instead of starting from informed analysis, simplistic one-size-fits-all insulation methods may be rolled out nationwide to meet short-term targets, with little thought given to the potential pitfalls and longer-term effects.

Just slapping insulation onto old buildings to improve their performance, without considering how they will work together, is probably as recklessly naïve as expecting an ordinary car to run better if it had rocket fuel in its tank. Any improvements might be quite temporary and ultimately costly – to the owner and to the environment.       

Insulation is often coupled with thorough draught-proofing. Old houses which originally had open fires were intended to work with lots of permanent, benign minor draughts (to feed oxygen to the fires that burned all year for cooking) that kept the house’s structure dry. And ‘dry’ for an old house means survival – better to resist rot, woodworm and mould. Trap the wet somewhere and decay follows. 

To suddenly, unthinkingly seal and wrap up an old, traditionally-built, house - as if it were a brand new state-of-the-art building - could potentially lead to a cycle of decay and repair in the longer term due to trapped dampness. This much has been established already in the thousands of old houses that have been unhelpfully partially sealed up due to a mis-match between the needs of old houses (to 'breathe') and the impervious properties of many twentieth-century ordinary repair and decoration materials (many of which were presumably designed for more modern buildings).

But unlike those cements and paints, insulation does not even have to be impervious to risk trapping damp in an old house or cottage, simply mis-applied (in a way that inhibits adequate 'breathing'). It is a delicate balance that even affects more predictable modern buildings: the UK building regulations were amended late last century to address problems arising partly from inappropriate insulation placement as well as reduced ventilation in roofs, for example. There have also been similar moves to address condensation occurring within the walls of certain modern constructions. Arguably, our older building stock is generally even less well understood and less well protected.

So far this article has only touched on the technical side of things; there is also the visual side. How do you apply extra insulation to an attractive old house or cottage without covering up or re-building some of the authentic old surfaces that are responsible for its visual appeal - and which probably also account for a great part of its financial worth? You can’t just whip off all the insulation when your friends pop round or when you want to sell the place.

Similar arguments have been aired for years about the ugliness of replacement double-glazed windows and doors manufactured in industrial materials, compared with the characterful hand-made originals. There are other, cost-effective, ways to insulate original doors and windows on old houses while retaining their visual contribution to the value of an old house or cottage intact. 

But isn’t insulation about sustainability? Shouldn't we all be doing our bit?

Well, a house that has lasted several hundred years is likely to have been originally built using largely locally-sourced sustainable materials and sustainable low-energy processes. That’s good in sustainability terms, and much better than we can manage now in mass house-building.

And then there's the durability of those materials and the energy that was embodied in old houses, which may have lasted a century - or two, or three or more. This represents a really excellent environmental investment. Cottages up and down the country have already comfortably out-performed the design-lives often quoted for modern energy-efficient houses, many times over.

Not only that, our oldest houses and cottages were designed to use wood as a fuel. Wood as a heat source is now frequently credited as being almost carbon-neutral. So that's good too, especially as few modern homes have an effective option to burn wood.

So, if old houses are already so incredibly sustainable why do we need to tinker with them to make them...sustainable?

The answer is that one critical element has changed from sustainable to unsustainable over the last hundred years. The occupants. Not only do people now tend to want to use old properties unsustainably - for example by heating every last inch of them beyond the necessities for health and comfort - those homes may also get redecorated in ways that also undermine the houses' health. And if all this damages the property, then we will be tying up more energy and materials in future repairs. That isn't energy-efficiency.

Insulation is about conserving the energy we have just consumed, and it can usually be improved, but so can our attitudes to the energy before we use that. People can, and do, live in old houses without spending more on energy than their neighbours in modern houses. They do this by simple common-sense measures and a robust attitude to avoiding waste.

This article is certainly not anti-insulation, it aims to add some perspective to a growing well-intentioned trend that is easily misapplied and which is feared to have the potential to harm old houses in the long term, and so cause energy and materials to be used up needlessly in the future - mending them.

At oldhouse.info we think that energy-efficiency is important and we understand that  people want to be as comfortable as their old houses can make them (and that there will inevitably be two-way compromises between past standards and modern expectations). To find out more about the general requirements of old houses and cottages - and how they affect the insulation of windows, doors, walls, floors and roofs – plus some ideas to develop, starting with simple and inexpensive measures that may be appropriate to improve your own home's insulation - take a look (at the green pages especially) inside these books…

        
click covers for details


...and please take a look at the rest of our site, and our other books and downloadable articles.  

 

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  The information contained on this website and downloadable articles is based upon areas of recent understanding in the field of historic building conservation in the UK and as such is part of an ongoing evaluation of how old buildings respond to changes in maintenance and use. This website and its articles aim to foster an understanding of the general issues involved in the maintenance of old domestic dwellings in the UK but cannot cover all aspects of all possible issues and is for information only and is not a substitute for specific professional advice. Information may be updated at any time without notice. Some of the processes, products and materials referred to may be subject to local regulations and laws governing permissions or the proper and safe use of materials and enquiry should be made of the appropriate local government authority. Old House Info Ltd has no control over how any of the information contained in its articles or elsewhere on its website or on any linked website or other publication is used and can accept no liability for loss, damage or injury however caused.

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