Tag: old houses

HPH033 : Are Conservation Techniques Becoming More Energy Efficient? – with Douglas Kent from SPAB
Douglas Kent from The Society for the Protection of Ancient Buildings explains how to look after period properties and what advances are being made with conservation techniques in order to achieve greater energy efficiency.

This podcast is about whether by conserving old buildings we can have sustainable and energy-efficient period properties.

Interview with Douglas Kent

Douglas Kent was brought up in Saffron Walden, a village with a deep and rich architectural heritage. Douglas believes this influenced his choice of career and is why he became involved with The Society for the Protection of Ancient Buildings (SPAB) in the year 2000. He is now the Technical and Research Director.

SPAB Aims to Save Old Buildings from Damage, Demolition or Decay

SPAB was founded in 1877 by the designer William Morris and its objective is to save old buildings from damage, demolition or decay. At the time it was established they were very much trying to prevent buildings being restored and rewound back in time. Douglas explains this with an example of how a church could have been adapted or reconstructed to what medieval masons should have done at the time if they’d built it properly in the first place. So their focus is on conservation and repair rather than restoration.

The Most Common Damage to Old Buildings is Often Unintentional

While the threat to old buildings in the past was outright demolition today it does not happen very often. Expansion of airports, such as Stansted, would however be something that could have a catastrophic effect on the historic built environment.

More often the damage occurs unintentionally by the way in which buildings are conserved. People use materials that don’t work sympathetically with older buildings and not just look different but perform differently.

Older Building are More Analogous to an Overcoat Rather Than a Raincoat

New buildings often rely on a system of cavities, barriers and membranes to exclude moisture and Douglas likens this to a raincoat. With an older building it’s more analogous to an overcoat so it allows some moisture to come into the building but it will evaporate out when the conditions change. Old buildings that work in this way are breathable.

Historic Buildings Are Protected in Many Countries

Douglas explains that although protection of old buildings exists in many countries, it varies hugely in the way it is implemented. The UK has three bands:

Grade I – this is the top band and accounts for the smallest percentage of buildings

Grade II* – these are still important buildings that also account for a small percentage of historic buildings

Grade II – the vast majority of older buildings fall into this category.

Finding out more about listed buildings from English Heritage.

There are also conservation areas, wider zones of protection and things like scheduled monuments.

When Improving Energy Efficiency You Must Avoid Creating a Warm Damp Building

Most buildings predating 1919 are considered breathable (as mentioned above) and therefore the energy efficiency measures must be appropriate. For example, lime mortar or lime plaster have this breathable quality to them. Using inappropriate materials to improve thermal performance could mean that a cold damp building becomes a warm damp building. This could trigger off things like rot, decay, rusting and mould. It could even aggravate human health ailments such as asthma and so on.

Original Components Often Have a Long Lifespan Left

As well as affecting the aesthetic qualities of a building, removing original period components can be counterproductive when you consider that they might have a long lifespan left. Douglas gives the example of when people take out single-glazed windows that are built with really good timber and replace them, perhaps, with plastic double-glazed windows where often the seals will go within a couple of years.

Research Where Your Old House is Losing Heat

Your goal should always be to retain as much as possible of the original fabric of the building and the overall essence of it. That can be achieved by using compatible materials and methods, and carrying out only work that is essential for the long term survival of the building. Also you should underpin that work with good information and a good understanding of the building.

For example, rather than blitzing the building with new windows, consider where you are losing energy. This could be done by carrying out thermal imaging or an air pressurisation test, which will help you pinpoint where the draughts etc. are occurring. This is a much more targeted approach rather than doing something and hoping for the best.

Secondary Glazing Can be Better Than Double Glazing

Research by Historic Scotland has shown that you can meet or even exceed the value of new double-glazing by upgrading existing windows using secondary glazing. So establish the full facts rather than rushing to make the changes because often the changes can save little energy and damage the building in the long term.

Providing Decisive Advice for Old Buildings is Difficult

Douglas says that at SPAB they are always refining their techniques. The difficulty is they are trying to base what they are doing on good information, which involves a number of research projects and that takes time. This has to be about robust scientific evidence.

Research Shows Actual Performance Often Exceeds Predicted Models

One discovery they have made is that in 77% of cases the U value, or thermal transmittance, of an old wall is actually better than the calculated value when measured in situ. This is partly because when doing the calculations they don’t know quite what the construction of the wall is and even if they do, there is often very little data that relates to those materials to enter into the software. If the data going in is not reliable then neither will the data coming out.

Supported by English Heritage and Dartmoor National Park Authority they have measured a range of different constructions and methods including wattle and daub, stone buildings, cob buildings and so on.

Establishing the Limits to Insulation and Airtightness are the Priorities

General conclusions that the SPAB are beginning to find is that insulating a traditionally built building below a U value of about 0.4 could result in the technical risks (described above) of mould, rot, etcetera. Equally when reducing the number of air changes per hour they are beginning to think that below about 0.4 or 0.5 there could be negative consequences.

More Research Must be Carried Out

Douglas is aware that a lot more research needs to be done as well as refining useful tools, such as the hygrothermal modelling software WUFI . More data could be used to really improve the quality of the information and thus the basis upon which bigger decisions are made. Although there have been some interesting and helpful findings this is still very much the beginning.

Old Buildings are Sustainable in Many Ways

Old buildings are frequently built of materials with a lower embodied energy than their new counterparts. They also often have a longer lifespan and are easier to repair too.

Douglas uses windows as an example. Timber windows can be easily repaired by a local carpenter thus extending the lifespan, whereas with modern counterparts there can be propriety systems. This means that if there are problems 20 or 30 years down the line and the supplier is no longer in business, then the windows cannot be fixed.

Older buildings commonly possess features that are conducive to good energy efficiency, such as really thick thatched roofs, thick walls that are able to retain heat and release it gradually and windows that are disposed to maximise daylight but minimise heat loss. Not only that but as many old buildings are constructed with a lime mortar this makes recycling at the end of the life cycle much easier.

Basic Maintenance Should be the First Step in Improving the Performance of an Old House

SPAB recommends a step by step approach, which always starts with basic maintenance. All too often people think about microgeneration and putting up wind turbines without stopping their gutter leaking! Correcting a leaking gutter will prevent the wall becoming damp and obviously a damp wall is an energy inefficient wall.

So undertake the basic maintenance first of all. Every year SPAB run National Maintenance Week to emphasise this point.

Secondly Consider the Quick Wins

This second step is about the things that have a short payback and cause little disturbance to the historic fabric of the building. For example, things like draught proofing windows and doors, topping up loft insulation and fitting thermostatic radiator valves and so on.

Finally Consider the Major Work

Only after completing the first two steps should you consider the major work. This might include upgrading the boiler and heating system, introducing a renewable heating source or reinstating a missing lime render externally on your stonework. Spending a little bit of time and money on targeting the measures (as described above) can reap big rewards later on.

A Passivhaus Retrofit is Not Appropriate to a Traditionally Built House

Douglas advocates that if a building predates about 1919 – in other words it is of traditional construction – then a traditional approach should apply. This includes 1 in 5 of the UK building stock, not just listed buildings.

Anything post that 1919 period, generally speaking, would have a much freer hand to consider alternative approaches such as Passivhaus and approaches that hermetically seal a building.

Older Buildings Must Not Become Seen as Liabilities

SPAB are not totally against thermally upgrading older buildings because they understand that if they become too expensive to run then they may become liabilities. This could lead to increased demolition which is obviously against their core objective.

However, Douglas does point out that as of the beginning of 2013 listed buildings no longer require energy performance certificates. Even before they were withdrawn, they were being taken with a pinch of salt because some of the recommendations did not add up. Commenting on retrofitting Douglas says: “We do need to be careful and to make them comfortable and fit for 21^st century living.”

Lifestyle is Just as Important When Saving Energy

Having an energy-efficient building is one thing but if the occupants aren’t sympathetic with the overall aim of saving energy then it defeats the point. It’s often been shown that people who live in some of the more energy-efficient houses are using them perhaps in a more cavalier fashion and with the money that they are saving from being energy efficient they’re going off and flying around the world. Therefore the bigger picture is sometimes more complicated than it may first appear.

Was William Morris in Fact the First Person to Talk About Sustainability?

Conserving old buildings is about keeping as much as possible of the physical fabric of the old building and that comes back to the principles that were set up by William Morris when he founded the SPAB in 1877. Therefore it could be argued that, albeit unwittingly, perhaps William Morris in encouraging people to save old fabric and not to consume more resources in putting up new buildings was one of the first people to talk about sustainability.

Find Out More about the SPAB

Transcript

Download a transcript of the interview with Douglas Kent.

Grand Designs Live

Ben attended Grand Designs Live and amongst his highlights from this year’s event was seeing the Cube Project. Dr Mike Page from the University of Hertfordshire designed a modern and practical micro-home (3m x 4m x 3m) in which a single person or couple could live a comfortable, low impact life. It illustrates, amongst other things, how we actually need much less space than we imagine.

There was also a session on retrofitting which included Paul King Chief Executive of the UK Green Building Council and Grand Designs presenter Kevin McCloud on the panel. Kevin’s recommended resources for retrofitting period properties were Old House Eco Handbook and Warmer Bath. Radical retrofits were not mentioned in the discussions.

However a few days before, in an article for the Telegraph, Sarah Lonsdale wrote about how period properties could become a luxury of the super-rich. By 2030 the predicted minimum income of a family wishing to live in a period house and avoid fuel poverty would be around £100,000 ($160,000).

Our Question for the Comments Section

Does conservation offer the best solution when making old houses energy efficient?

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October 9, 2013
HPH032 : Insulating a Period Property – with Tim Hulse from EcoVert Solutions
Tim Hulse from EcoVert Solutions explains what insulation is and why there are often trade-offs to be made when selecting insulation.

Interview with Tim Hulse

While studying at the Centre for Alternative Technology Tim did his masters thesis on how to make old buildings in conservation areas zero carbon. A lot of his work these days at EcoVert Solutions is upgrading period properties.

Insulation Reduces the Heat Loss

Thermal insulation is simply a way of reducing the heat loss (or heat gain) through a building element, whether it’s the floor, the ceiling, the windows or the walls. This allows you to create a barrier between two areas of different temperatures.

The Type of Insulation Needed Depends on the Project

There are lots of considerations to take into account when selecting insulation. Tim gives a few examples: it will depend on the type of building (old or new), the budget available, the desired durability of the product and whether you want to use a sustainable material or are okay to use an oil-based material. There may also be issues with moisture to take into account.

Choose Materials That Complement the Construction Method

When it comes to new buildings Tim says that there’s a move away from brick and block. There are just many more options than the traditional construction methods, such as a timber frame with render on the outside, the Ziegel ThermoPlan based clay system with render or it could be a brick exterior with a timber frame on the inside, and so on.

In other words it’s important to think about what the construction method should be and then what materials would best compliment that method. For example, a natural material like sheep’s wool or WARMCEL recycled newspaper might be a good idea because there would be fewer issues with trapped moisture.

Architects Often Stay Within Their Comfort Zones When Specifying Insulation

Tim says that if an architect is used to working with traditional materials and methods, he or she is probably going to stick within this knowledge base. This is because there are going to be more builders around that are familiar with building this way and they’re going to be more sure about the result they expect but that’s only because their expectations are limited.

U Values Allow You to Compare Different Materials for Thermal Performance

A U value is a measure of heat loss through a building element. The greater the U value the worse the thermal performance. Sustainable materials (such as wood fibre, sheep’s wool or recycled cellulose) generally have a U value of around 0.4 whereas oil-based products perform better at about 0.2. Aerogel gets even lower at around 0.1. Therefore when using sustainable materials you often need a greater thickness to achieve a better thermal performance.

Allowing 500mm for the wall thickness accommodates any kind of building solution that will result in a U value that meets Passivhaus requirements.

Materials Have Different Abilities to Buffer Heat

While sustainable insulation materials have similar properties in terms of thermal performance, they’ve got differing abilities when it comes to buffering that heat. This means that heat will transfer through one material more quickly than another. Tim gives an example of how this is useful in a loft when you don’t want it to overheat. By the time the outdoor temperature is at its peak, the indoor temperature in the loft is still lagging because of this decrement delay. In other words it never reaches the extremes of the outdoor temperature.

Trapped Moisture will Quickly Damage a Building

Tim explains how he solved a recent issue with a Grade II listed house. The ground floor extension was suffering significantly from damp, which turned out to be trapped in the building both by concrete outside the building (above the internal floor level) and concrete inside the building with plastic sheeting under it. This only really left the walls as a means of escape for the moisture in the ground. The effect of this was rot and mould on the walls, plus it created an unhealthy environment.

The building fabric was addressed first. Tim’s solution was to dig a French drain outside at a suitable level. On the inside they dug up the concrete, got rid of the plastic and installed a Limecrete floor using 300mm of recycled foamed glass aggregate, which is breathable. As it’s not capillary active the moisture cannot to seep upwards towards the Limecrete.

Tim talks through some of the other elements of this retrofit. 50mm of fibreglass insulation in the ceiling was replaced with 300mm of sheep’s wool insulation. The ventilation in the attic was improved. Once the floor and the ceiling had been dealt with, 60mm of Pavedentro wood fibre was screwed-fixed to the external walls. Then the old windows (that were not period) were replaced with higher performance windows. Once all the structural elements were in place, it was made airtight. Pro Clima tapes were used to seal around the windows and then a lime render was applied. [Tim goes into more detail why he made these decisions.]

Increasing Comfort and Tackling Mould are the Most Common Client Concerns

In spite of all the talk about emission reductions and reducing bill costs, Tim finds that most people are generally concerned about two things. They either want to improve their comfort because they are too cold in the winter or deal with particular issues like mould. Tim’s work often deals with one particular area of a building and then once the occupants live with the improvements they often go on to do more work.

Expect Disruption During Your Retrofit

When Ben suggests that cost might be restricting people from doing whole house retrofits, Tim says that the disruption is often the main factor. Not only do plasters and renders take a number of days to dry out, drawing the process out, but there’s dust and noise with which to contend as well.

Consider Whether Interventions Will Impact on the Ability to Use a Room

When insulating internally, think through what the rooms are going to be used for. What you don’t want is the intervention to impact on the ability to get use out of the room. Tim illustrates with an example of a 70s house he’s recently upgraded where he used aerogel on one wall because otherwise the bed wouldn’t have fit in the room any more!

Sheep’s wool insulation

Natural Insulation Products Have Additional Benefits

Not only do natural materials have a lower embodied energy, but they are generally better for the occupants. They tend to buffer moisture well and can help maintain good humidity levels within the house, which in turn reduces the incidents of dust mites. Natural insulation also absorbs CO₂. Even with these benefits sustainable materials won’t be right for every situation.

Insulating Externally has Pros and Cons

This is the equivalent of wrapping a big blanket around the house! While it’s technically the easiest thing to do and it eliminates thermal bridging, it will alter the appearance of the building. When dealing with older buildings, these are the very features that give the places charm and curb appeal.

Internal Insulation Can Have Less of a Visual Impact When Detailed in

So long as moisture does not get trapped (and cause damage) internal insulation can be easier in a sense. There’s no need for scaffolding and any fancy architectural moulding on cornices, for example, can be rebuilt using a lime plaster. They can be run in place or built off site and stuck in place after. In other words you may not be able to tell the difference.

Old Buildings Have a Lot of Embodied Carbon in Them

Tim refers to research from the Oxford Brookes University that’s shown that the embodied carbon in old buildings is still worth keeping (rather than demolishing these buildings and starting again). While you’re unlikely to upgrade an old house to the Passivhaus standard, the reality is that a 60% improvement in performance would be huge, particularly when there’s little overall progress in retrofitting the existing housing stock.

Behaviour Can Have a Big Impact on Energy Use Too

Tim’s own research has discovered that people often think they are being more green than they are, but when it comes to behaviour they’re still not doing all that they could. Therefore making a house more efficient is great but it needs to be combined with living in it in a sustainable way.

Use Analysis Tools to Model the Moisture in a Building Element

When it comes to older buildings, thinking through condensation is really important. The software WUFI is one way to model the behaviour of a building element. For example, it could model the balance of moisture in the wall over a period of time, using historic data based on the location. This means you get a sort of time-lapse movie of your building before and after interventions, which demonstrates how it’s performing and whether it’s actually going to offload all the moisture that it’s accumulated.

It’s far better to use this method rather than the simpler Glaser method that some manufacturers of non natural materials use, which favours their products but really doesn’t show the whole story.

There May be Limits to How Much Insulation Can Safely be Put on Old Houses

There is ongoing research into how old houses behave when insulation is added and recently there has been evidence that you need to be careful. If you try and increase the U value too much you could potentially cool down the wall. So you’re not allowing the internal heat to warm up the wall enough that during the summer it’s going to offload all the moisture that it’s accumulated.

Currently the thinking is around a U value of 0.5 which Tim says isn’t great when you look at something like a Passivhaus U value. Where solutions haven’t been thought through properly, damage due to interstitial could occur 10 or 15 years down the line. This will make all the hard work a waste of time.

Listener Questions

Tim helps answer a couple of listener questions. Neil Barnes wanted to know what is the most sustainable and economic insulation to use, and Bill MacGregor wanted advice on increasing the insulation levels on a 1980s timber-framed house.

Transcript

Download a transcript of the interview with Tim Hulse.

Follow Tim Hulse on Twitter

Our Question for the Comments Section

What insulation will you be using on your project and why?

An Early Air Test on a Straw Bale House

Ben talks about a recent visit he made to Fran Bradshaw’s straw bale house. Barbara Jones from Straw Works was keen to observe how the straw would perform on its own before the clay plaster was applied internally and the lime render was completed externally.

Check out Anne Thorne Architects’ blog on the project for more details.

Two Podcast Recommendations for Architects

Business of Architecture – Enoch Sears aims to help small firm architects attract more clients so that they can take their businesses to the next level.

Entrepreneur Architect – Mark R. Le Page believes that architects can be financially successful as well. He shares stories of the people doing this today along with personal insights.

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September 25, 2013
HPH016 : Finding The Balance Between Heritage and Sustainable Design
What’s more important – preserving heritage architecture or retrofitting it to high energy efficiency? In our first forum on a Google+ Hangout we discuss some of the issues.

The Panel

Writer and blogger Roger Hunt (who appeared in our 10th podcast)

Writer and Passivhaus consultant Adam Dadeby from Passivhaus Homes (who appeared in our 5th podcast)

Homeowner Ross Atkin (who has recently retrofitted his Victorian house)

This debate was primarily focussed on buildings that were constructed before 1910 or the time when building technologies changed.

When Retrofitting, There is No Single Approach That Fits Every Building

In historic buildings where the façade is a strong part of the character, externally insulating would not be appropriate. However, just as importantly, internally insulating would cause major disruption as well, particularly if many of the original features are intact. So, when retrofitting an old house for energy efficiency, each building must be assessed individually.

From a purely energy point of view and from a moisture point of view it’s much better to insulate on the outside of a wall and to wrap the existing building in insulation.

Old Houses May Not Need a Deep Retrofit

If the definition ‘old houses’ is a small enough percentage, for example between 5% and 10% of the total housing stock, then it is possible that these houses could be retrofitted in such a way as to minimise damage to their character. If energy consumption were reduced, perhaps by 50%, while the remaining 90% or 95% of the housing stock is brought up to Passivhaus levels, saving 80% or 90%, then the overall the situation would be much more in line with where it needs to be.

Occupants of Old Houses Must be Willing to Live Like the Inhabitants of the Previous Centuries

In an energy constrained future, for those who choose to live in an old house, compromises must be made. The inhabitants must consider that they adopt a lifestyle that is more like how things used to be in previous centuries, where they lived at colder temperatures. In winter, the inhabitants might retreat to a smaller portion of the house. Since the 1970s the temperatures of our homes have gone up from 12 degrees to 19-20 degrees (on average).

Old Houses Could be Vulnerable if Not Made Energy Efficient

There is a danger that as energy prices increase, people are not going to want to buy buildings unless they are energy efficient. As it is easier to construct low energy buildings from scratch than it is to retrofit them, more old houses could fall victim to demolition. Making old properties as energy efficient as they can be without destroying the character will help. The rest is down to accepting this overall colder temperature, which will only be in the winter months anyway.

Simple Measures Can Really Improve Energy Efficiency

There is a lot that can be done to improve energy efficiency that isn’t going to cause damage and destroy the character and value of the buildings. For example, draught proofing is relatively easy to do and doesn’t have a huge impact on the building. A certain level of insulation can be done without having a huge impact on a building.

Every house must be individually understood and then appropriate measures should be carried out in a sensitive way.

A Passivhaus Retrofit for Many Old Houses Wouldn’t be Appropriate

Retrofitting an historic house to Passivhaus standard by insulating internally would effectively involve building a house within a house. That would mean gutting the place. While this could still be appropriate where significant damage has already occurred, for example the Princedale Road Passivhaus in West London, it is unlikely to be a solution to roll out.

The UK is Stifling Advances with Conservation Overkill

The balance between conservation and actually providing housing that works for people in terms of health, energy costs and the environment is weighted too heavily in favour of conservation in the UK. The planning system often treats everywhere as a conservation area, when this is not the case. All this does is preserve the status quo rather than allow progress.

A Proportion of Society are Stuck in Their Period Properties

With investment in social housing, the very poor are getting a much better standard of housing. Those that are wealthy can also afford to self-fund energy efficiency measures. However, there’s quite a large percentage of people in between, either unable to fund changes or perhaps stuck in rented accommodation. These people aren’t choosing to stay in heritage accommodation, it’s simply what is available and what they can afford.

There Needs to be More Education

People still do not seem to have the knowledge of how they can make their homes better and more energy efficient. Even those who live in eco houses quite often do not fully understand how to live in them. There needs to be more help available.

Social Housing is Leading The Way in Eco Retrofits

It doesn’t seem to be volume house builders that are leading the way, but housing associations. They’re the people that are experimenting, coming up with the ideas and solving the problems. There is a lot to learn from the social housing sector.

Need to Solve Damp Issues

No house should have damp issues, but they can stem from mistakes that have been made in the past. Before retrofitting a house these issues should be addressed because a damp house is a cold house and a wet wall is a cold wall. Stopping dampness will create a much warmer and more environmentally friendly house in the first place.

In the UK, VAT Encourages New Builds

Paying 20% VAT on retrofits as opposed to nothing on a new build sends a clear message. As retrofits are more complicated anyway it does favour knocking buildings down and starting over again, especially in areas where skills are limited.

The Focus Should be on Creating Decent Homes

Lifestyle plays a big part in energy efficiency so it’s not just about buildings. For example, switching on all the lights and leaving the windows open in an energy efficient house will have a negative effect. So while the fabric of the building is important, there is also a fundamental lifestyle change that must be adopted. The future of housing should be creating decent homes for people, considering the environmental aspects, the energy usage but also things should be clean, dry and healthy.

Transcript

Download a transcript of the debate.

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February 20, 2013
HPH010 : Can You Damage an Old House When Making it Energy Efficient? – with Roger Hunt
Roger Hunt explains how to make a period property energy efficient without damaging the building or creating problems for yourself in the future. Also House Planning Help gets its first guest blogger, Paul Mallion from Conker Conservation.

Interview with Roger Hunt

Co-author of the Old House Handbook Roger Hunt has just finished work on a companion volume called the Old House Eco Handbook (which will be available in March 2013). Although the first book was written in 2008, Roger says environmental issues and energy efficiency have now become much more pressing and so the time is right to focus on how this can be achieved for old houses.

An Old Building is a Solid Wall Building

The Old House Eco Handbook is in association with The Society for the Protection of Ancient Buildings. If you own a period property that was constructed anywhere from the Medieval era to the Edwardian period, then this book aims to help you. Roger points out that after the Edwardian period building technology started to change and move away from solid walls to cavity walls. Lime-based products became less popular while the use of cement-based materials increased.

Lime-Based Materials Work in a Very Different Way to Cement-Based Materials

In an old building it’s not about keeping the water out, as the walls absorb moisture. Both the inside and outside walls are constantly absorbing moisture or allowing it to evaporate out. Modern cement-based materials try to keep water out of the building by using impermeable layers. Mixing the two methods causes problems.

Old Buildings are an Essential Part of Our Landscape

Roger believes that old buildings are not only part of the landscape but part of our communities. Getting rid of them will break up communities and destroy landscapes. Towns and villages have grown very organically through the years with little accretions, creating much-loved wibbly-wobbly streetscapes. In his opinion removing the old to make way for the new would be a bad move, not to mention all the embodied carbon and historic detailing that would be lost.

Take a Holistic Approach to Energy Efficiency

View your house as a whole and don’t just do one thing in isolation (like putting solar panels on the roof). Take time to consider all the things you could do. For example, loft insulation can make a big difference and it’s a relatively simple project. Draughts can make a building feel colder than it is, so deal with those sorts of things.

Keep Original Timber Windows

Roger illustrates the point by suggesting you wouldn’t throw out an Edwardian chair because it had a damaged leg – you would get it repaired. In the same way if you have original windows you should not be looking to replace them with double glazing. Instead get them repaired and also draught-proofed at the same time so that they perform better, too.

Simple Measures Can Often Make a Big Difference
- Draw curtains and blinds to make a room warmer.
- Put a wooden flap over the letterbox to stop the draughts coming in.
- Use a fabric sausage to stop draughts coming under doors.
Passivhaus is an Excellent Standard for New Builds

Roger is a great believer in Passivhaus and he thinks that it can really produce high performing houses.

Bringing an Old Building up to Passivhaus Standard is Quite an Invasive Process

Roger has seen retrofit projects himself and he agrees that they have reached a high level of energy efficiency. However, the problem is the loss of character and historic detail of the building. These are the very features that make these buildings desirable in the first place. A Passivhaus retrofit means losing a lot of the original fabric of the building and balanced with the carbon, Roger is not sure whether it adds up. Some of those materials are irreplaceable once pulled out.

No Single Solution Works For Every Building

The holistic approach is about insulation and finding the right energy generation methods to suit the building. If you’re in a very old leaky building in the countryside a biomass boiler might be the answer. If you’re in a town, an air source heat pump might be the answer. Every building is different.

A Passivhaus Retrofit Would be More Appropriate if a House Had Already Lost its Original Features

When Ben explains that he didn’t notice any loss of character in a recent Victorian Passivhaus project he saw, Roger stresses that he is not against a Passivhaus renovation in the right circumstances. However, where original features exist such as dado rails, skirting boards, cornices and windows, he believes this is a lot to lose.

Retrofitting Old Houses is Something We’re Still Learning About

This is not something that is set in stone and different people have different ideas on how it should be done. Putting together the Old House Eco Handbook has involved a lot of research to understand the current thinking. Roger believes this thinking will evolve as better ways of doing things are discovered. There is a fear that what is being done to many buildings will have to be ripped out in 10 or 15 years because of damp problems, etc. This would clearly not have a positive impact on the environment either.

Don’t Slap on Wall Insulation Without Understanding the Science

Although this book is offering solutions, it’s also saying in many cases don’t do anything. This does not just apply to you but to the wider community. So tackle all the other simple measures first to make the house warm and air tight, and perhaps leave wall insulation for a later project. Balance the cost versus the gains, bearing in mind the potential risks of trapping moisture in the wall.

Insulating Will Lead to Loss of Features

Whether you insulate on the outside or inside of an old building you will lose features. While it’s easier to insulate the outside of a building, insulating on the inside of the building is generally considered to have less aesthetic impact. There is also a risk of interstitial condensation occurring where the warm air meets the cold surface and dampness occurs. The science of this is not fully understood. This can cause timber in the wall, for example, to become rotten.

Moisture Levels Are Being Monitored

A lot of test projects involving wall insulation are underway at the moment. Wireless moisture sensors are being embedded in the building materials to see whether there are really any problems. This is something we will only find out over time.

Think Beyond The House to The Neighbourhood

Good design looks beyond the house to the neighbourhood. Roger uses an example of why a cluster of 12 houses might be a good idea, because it would be possible to for you to know all of your neighbours. He also says simple things like a bench out on the street or low garden fences to encourage interaction allow for good sustainable development.

Good Modern Design Needs to Meet Regional Variation

As an advocate of modern architecture, Roger likes simple white rendered buildings. However, he is aware that it would be a bit boring if they were everywhere. The character of a place is down to the variety of materials used there. In the past houses would be constructed with materials that were available locally and Roger would like to see modern design adapted to reflect this regional identity.

Grade 1 and Grade 2* Listed Buildings are Difficult to Make Energy Efficient

Roger is adamant that we need to improve the energy efficiency of our buildings. He does, however, think that buildings of historical significance are difficult to deal with and suggests that perhaps these buildings should remain as they are. It is the bulk of the housing stock that needs to be addressed.

Classic Cars Still Exist as Classic Cars

Roger talks about a picture in the Old House Eco Handbook (affiliate link), where a Morris Minor is parked in front of an Edwardian House. While cars have changed hugely in terms of energy efficiency, it does not mean that the classic cars have been updated with today’s technology.

Everything is a Balance

While future generations may love us for making old houses more energy efficient they may hate us if we destroy what was good about them.

Check out Roger Hunt’s Blog
- Huntwriter
Transcript

Download a transcript of the interview with Roger Hunt.

First Guest Blogger on House Planning Help

We’re always trying to create more great content and one way of doing that is with the help of a few carefully chosen experts. Paul Mallion from Conker Conservation has become the first person to write a blog for us and we are very grateful to him. Read his article about why white paint is potentially a colour you don’t want to use.

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December 4, 2012