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Friday, 10 February 2012

Eco Renovation – Are Old Buildings Plight or Remedy?

A Wasting Disease

Part of being more careful with the environment and our impact on it is not to be so wasteful. Energy is an ever present element in this. That can be directly by leaving the door open in the middle of winter or indirectly when food that was never going to be eaten is thrown away and the gadget that has lost its novelty appeal ends up in the bin while still working perfectly.

All these will be replaced – the heat that has escaped, the leftovers that have been forgotten in the fridge for so long they jump out and strangle you, the i-Whatsit whose one major fault is that it is last year’s model. And every time wasting energy is inescapable, because we use it when we try to stay warm, go to shops to buy something new that wasn’t necessary, that certain something is being produced.

The same goes for throwing away buildings. When there is talk about eco-friendly houses normally we are thinking of property not even built yet. The growing trend of reducing our impact on the environment concentrates on the latest technologies and discoveries. ‘New’ and ‘better’ are words uttered in the same breath by politicians, developers and environmentalists with unfailing regularity – groups not usually known for the harmony between them.

But the good old stuff has a lot to offer. For a start a lot of energy went into building a property in the first place, no matter whether it was yesterday or 200 years ago. In an article in Time Magazine Bryan Walsh spoke of “…65 years [it would take] for the reduced carbon emissions from a new energy-efficient home to make up for the resources lost by demolishing an old one.”. Although that time span probably will vary depending on one’s own definition of ‘energy efficient’, it is still a sobering thought.

Country House

Demolishing a building to make way for something with a bag full of eco-credentials might seem the logical thing to do when looking simply at the advantages, perceived or real, a clean slate will offer. However, that is not always an option. If it is a listed historic building we are talking about, whether residential, official or commercial, the accepted fate is often that it is ‘part of the character’ to be as cosy as a medieval dungeon. Planners and those professing to protect our architectural heritage might try to prevent any efforts deemed to corrupt the historic soul of a property.

Neither is a wholesale replacement of old property stock realistic. According to the Carbon Trust in Britain 70% of buildings in existence today (2012) will be around in 2050. With ambitious targets for reducing energy usage being set world-wide it is high time to concentrate on improving what we have got already. So what can you do but, more importantly, what will you be up against?

The Technical Stuff

From a purely technical point of view it is not that difficult. There are two main areas to consider: insulation and energy generation.

Insulation

The basic criterion here is whether you have a solid wall or a cavity wall in front of you. That gives you the basis for the choice of external, internal or core insulation.

Cavity walls were introduced in the 19th century but have become really popular with the advent of greater attention to heat loss. That is simply because the cavity – or core - can be filled with an insulating material, such as glass wool, cellulose or foam (e.g. polyurethane). Now, you might argue that the air between the brick skins actually is a very good insulator but whatever is injected is not supposed to squeeze the air out, only to make it immobile. That enhances its insulating properties.

External insulation, on the other hand, is what you would go for with solid walls of brick, stone, etc. These are systems of either foam blocks fixed to the outside with an adhesive or fitted as part of a stud wall. In both cases a top coat is applied as finish.

It is then possible to add insulation on the inside with much the same materials. Also in use are multi-layered sheets, made up of various materials including polypropylene, polyethylene and foil. This achieves the same properties of 20cm of a conventional material in about 4cm of thickness.

In all this windows must not be forgotten. Single glazed units are obviously not good for the environment but even older double glazing loses its lustre over the years. Modern double and triple glazed windows are necessary to complete the picture.

Energy Generation

Here too you won’t find any big surprises. If you can provide the right conditions you might be able include a wind turbine (see Small Scale Wind Power) or bio mass (anaerobic digestion). In most cases, though, it will be more suitable to fit solar panels, ground source heat pumps or air heat pumps.

A Complex Business

So far, so good. It would look as if we were on to something, wouldn’t it? Retrofitting our existing buildings for a low-carbon future seems to be a done deal.

Unfortunately, if I have made you all excited and slobbering over catalogues with sexy photovoltaic panels already, I have to step on the brakes. As you will see, some due diligence is required before you get started. The Energy Saving Trust, a British not-for-profit organisation, stresses in its comprehensive report The Retrofit Challenge: Delivering Low Carbon Buildings that “[performance] predictions of [retrofit measures] in general tend to be based upon the assumption of ideal behaviour of materials and products under standard conditions, combined with perfect installation. It is therefore perhaps not surprising that in reality performance rarely matches expectations.”

Of course, it is better in principle to start somewhere than not at all, but renovating an old building with an emission-free future in mind is not easy. The report continues: “ [The] … the diversity of … building stock in terms of age, use, materials, build type and quality, thermal mass, location, orientation and occupancy, means that solutions need to be specifically tailored to the building or group of buildings in question.” In other words, for any efforts to be reasonably effective it won’t do to go out and get a few rolls of rock wool. What you do, in which steps and to what extend depends on the individual analysis of the building you have in front of you and the people who live or work in it.

Step Away, Look and Listen

It is important to realise that proper insulation and installing renewable energy generators are never worthless. If you cannot do it all in one go it is perfectly fine to plan a renovation in steps. The key is, to look at converting an existing building into a low-carbon property with an holistic eye. Just plonking in a bit of sheep’s wools here and a couple of solar panels there because they promise a lot on paper will leave you disappointed. Together they will never perform as it ‘says on the tin’. Individual measures might be sound choices in themselves but will need to fit into a whole that has been designed on the back of your individual situation.

A selection of the factors that are part of a successful conclusion to such projects are

  • What is the building made of?
    • Parts
      • Walls
      • Floors
      • Roof/s
      • Windows/Doors
    • Materials
      • Brick
      • Stone
      • Concrete
      • Timber-framed
  • How is it used?
    • As a home
      • By how many people?
      • What kinds of habits, needs and wants do they have as far as their home is concerned?
      • How might it be occupied and used in the future (as far as that is possible to predict)?
      • When is it occupied?
        • All day or just at certain times because people are
          • At work
          • At school
          • Enjoying leisure activities
          • Working from home
          • Suffering from ill health and stay at home
    • As an official building
      • Again, by how many people? A dozen or a thousand?
      • Does it have just one use or multiple ones?
        • For example, offices combined with a couple of workshops and a community centre versus a clinic
      • Is it just functional or does it have to be representative?
      • Is it perhaps a place of worship with its very own special characteristics and conditions?
    • As a commercial building
      • And again, by how many people?
      • Is it used day and night or just at certain times of day?
        • For example, shop versus manufacturing (shift work)
      • Does it have special climatic requirements?
        • For example, do certain rooms need to be cooled/heated/dehumidified/humidified etc.?
      • Can any of these requirements be integrated into the system in a helpful way?
        • For example, can warm water from a cooling device be fed into the heating system?

As you can see, there are numerous questions to ask. In an ideal world it would be possible to answer them all in a perfect way with a perfect solution. Of course, life isn’t like that but there is an awful lot we can do to turn our existing stock of properties into future-proof shelters without abandoning comfort, usability or functionality.

Puppy in front of fire place

The Alternatives

To be honest I cannot see any. We are not creating new buildings quickly enough and in sufficient numbers, whether in our so-called developed world or anywhere else on this globe. Therefore, the property we have now is not a disposable remnant of the environmental dark ages but the brick-and-mortar safeguard for our green ambitions.

What we have to do before we embark on a project is to step back, look and listen – to ourselves, the clients we might advise, everyone who will be affected and most importantly the building we want to convert. If we treat it as nothing but an empty shell, that is exactly what it will be. Taken seriously and as a living, integral part of its future use, it will act as a conduit towards solutions that complement each other and we can happily live with.

Value for Money

An argument that is often heard is that retrofitting is expensive. In many cases that is true. Sometimes it reaches levels where people dispute the financial viability and suggest tearing everything down and building from scratch.

Admittedly, when looking at it from an angle that is provided purely by adding up the bills this makes sense, but as we have seen that is short-sighted. An old building is more than a pile of bricks. In its walls it harbours energy and expense that does not need to be spent again. Without taking that into account the calculation is flawed. Not to mention all the materials that are not recycled but end up on a landfill site. A life cycle assessment quickly tips the scales back into renovation's favour.

So, don’t be disheartened. If you can do it as one big project with every element in place all the better. Planned well a one-bit-at-a-time approach is almost as good and very much worth pursuing. Studies have shown that in the end costs are almost always neutralised by greater comfort, savings on energy bills and higher property values.

 

See you next week

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