Tag Archives: energy efficient building
The planet faces an unprecedented series of environmental crises including climate change and the collapse of bio-diversity, yet for our construction industry and particularly the carbon-emitting housing sector it’s ‘business as usual’. Ecomerchant asked Sandy Patience, architect and editor at GreenSpec for his take on the paradox.
People don't buy, and the Government doesn't legislate for, future-proofed homes: Why not?
Why are we set on building houses that will cost owners and the rest of us dearly in the future? What follows, explores the complex reasons that have resulted in a perfect storm and the failure of the Government to provide adequate legislation.
Why are housebuilders selling us a lie?
My current walk to school alongside the new 'St. Michael's Fold' housing development provides me with an example of just how far volume housebuilders have travelled towards sustainable construction. The news is that it's not very far.
Some 30 houses are under construction. Brick and block with minimum cavities; lofts are waiting for the contractor to unroll the insulation; dummy chimneys and PVC windows surrounded by gaps through which you could slice a ping-pong ball. Each house is fiercely independent of its neighbours even if they are only a metre away - detached properties, of course, fetch premium prices. It's hard to detect evidence that the developer, or buyers, or planners, realise that we have a climate crisis and that new homes will be quickly rendered unfit for purpose.
The maximum wall area, using conventional materials, provided by detached houses ensures that they will lose heat in winter and badly overheat in summer. Given too, the rock bottom prices in the PV market and cheap hot-water collectors, it's surprising that the developer has declined to offer his customers their benefit. The on-site sales centre confirms that the houses are 'fully compliant' with building regulations. "Our buyers don't ask for any more than that." says the sales assistant looking sheepish.
For this particular estate, it gets worse. Sitting next to drainage ditches that criss-cross the landscape, this is essentially marshland incapable of sustaining much more than frogs. The site is so low that it's hard to see its survival much beyond a couple of floods from the nearby river as water levels rise. It's enough for an insurance man to break into a sweat.
Why are so many environmentally ill-equipped properties sold even before they're built? As in so many similar developments, the clue is in the hoarding size graphics at the entrance. 'Welcome to St. Michael's Fold'. St Michael is a local saint. A fold is where sheep are kept. The image is bucolic. Desirable. In the show house, the sales assistant shows us the 'period' features we can expect with our homes. It's another slice of ubiquitous 'Ye Olde England' signified by stick-on half-timbering, hanging tiles and 'leaded' lights. These are the bastard grandchildren of the Arts and Crafts movement.
Everything about how this development appears is fake. Fake history. Fake houses. Also fake too are the developer's claims that they have built homes for the future. No one is born to like country cottages or loathe terrace houses. The homes sell like hotcakes.
Why do we buy into Ye Olde England myth?
In contrast to most of the Continent, there's an association between Anglo Saxons and the detached house. Go to any suburb in the English-speaking world, be it Vancouver, Boston, Melbourne or Birmingham and you'll find detached housing built as default. Debate still runs about the origin of this, formerly English, phenomena. It derives at least from both the classic 'Englishman's Home is his Castle' icon and the need for differential from collective housing. Above all, it is a status symbol. For most people, it is the single most crucial signifier. Irrespective of the cost, the size and fitness for the purpose of being a home - it is the sign of having 'made it'. The Range Rover, another status asset, should have enough room to park in front.
The flight from industry
The Industrial Revolution gave us Blake's 'Dark satanic mills' - islands set in seas of Victorian industrial housing. Housing in an environment that we would describe today as toxic: Child mortality hit new peaks in the nineteenth century and in 1860s Liverpool, life expectancy sank to 25 years. No wonder then that a newly wealthy middle class chose to evacuate the city in search of AE Houseman's 'blue remembered hills' and the 'land of lost content'. There they built what they dreamed they'd lost. The pastoral fantasy reached its peak in 'Garden Cities' such as Letchworth, Welwyn Garden City, Bournville and New Earswick.
For many, the collective memory of row upon row of straight Victorian 'two-up, two-down' terrace housing still haunts. Now relatively wealthy, we build the opposite. We cherish the cosy curves of the avenues (note: not 'streets'), closes, meadows, ways, rises and drives. The price we pay is a needlessly low-density sprawl of housing estates. From a conservation view it's a losing strategy - not only is it an inefficient use of land, but many of the houses will be ill-aligned to make the best use of the sun and provide protection from the elements.
Will the Building Regulations protect us?
Expecting Building Regulations to set the standard for tackling Climate change would be a category error - the Regulations are not designed for engineering environmental policy.
Part L owes its origins, not to an environmental crisis, but an economic one. It wasn't until the 1960s that the Building Regulations expanded from protecting life and limb from bad construction to protecting our wealth. The introduction of statutory U-values for building envelopes in 1965 was only a gesture towards minimising energy wastage.
Come the 'Oil Crisis' of 1973; energy policy was revolutionised. Previously taken for granted, energy became a weapon in world politics. Dependence on oil turned into a liability - cutting off the flow could ruin a nation's economy. Nearly all Western governments introduced ranges of inhibitions on oil's use. The UK Government began requiring a U-value of 1.0 for external walls. Over subsequent years the U-value screw has tightened in line with oil and gas prices. Consequently, energy efficiency has significantly improved over the last 50 years, but it still falls far short of being a useful tool sufficient to realise any environmentally relevant standard.
Part L stands in an odd place. There's still the commercial imperative for fuel efficiency, but shouldn't it be the first legislative measure by which we prepare our building stock for global warming? If the industry was serious about climate change, wouldn't we have the appropriate regulation by now?
That, of course, would depend on Government policy.
The independent Committee on climate change (CCC) published the 'UK Housing: Fit for the Future?' in 2019. It condemns 'The way new homes are built (and that they) fall short of design standards. This is unacceptable.' The report calls for 'Immediate Government action … to ensure the new homes planned across the UK are fit for purpose, integrating the highest possible levels of emissions reduction' and that 'This will require an ambitious trajectory of standards, regulations and targets for new homes…'
So here's the problem: since concerns about global warming became public in the 1990s, fossil fuel-funded think tanks have framed it and other environmental issues as liberal and radical ideology designed to undermine capitalism. Pushing this agenda is a right-wing doctrine that claims that global warming is a hoax; that we shouldn't abandon coal, oil and gas.
The Conservative party already has form. The most crucial casualty of ideology was the plan to make new housing 'Zero Carbon' from 2016 onwards. Introduced by the Labour Government in 2007, it required new-build housing to be net-zero carbon through day-to-day running. Early in his premiership, Conservative Prime Minister David Cameron claimed that his was going to be the 'greenest Government ever'. It wasn't to be. That same Government, funded by the oil and gas sector, retreated from the 'Zero Carbon' commitment only months before it came into play. George Osbourne, the Chancellor, cited that constructing Zero Carbon Homes would be 'too expensive'. The Home Builders Federation added, helpfully, that '… new homes were already energy efficient under existing regulations'.
Of course, the 'extra expense' argument was nonsense. The building industry had a decade to bring construction up to scratch. Non-legislative standards such as the widely adopted Passivhaus showed that getting too demanding levels of energy efficiency added perhaps 1-2% to the cost price of a new home. Contemporary researchers at Cardiff University demonstrated that a zero-carbon house could even be built within the cost margins of social housing.
However, the door had been slammed shut. Other Conservatives expressed similar fears to the Chancellor:
'…we should not sacrifice Britain's economic recovery on the altar of climate change.' David Davis MP
'If you assume the worst then there is absolutely no point in spending any money trying to prevent inevitable climate change.' John Redwood MP
'People will die this winter because of the environmentalist obsession with the end of the world' Jacob Rees-Mogg MP
'…global leaders (are) driven by a primitive fear that the present ambient warm weather is somehow caused by humanity; and that fear – as far as I understand the science – is equally without foundation.' Boris Johnson MP
Beyond these shores are fellow travellers including one notorious conspiracy-monger who 'tweeted':
'The concept of global warming was created by and for the Chinese in order to make US manufacturing non-competitive.'
'This very expensive GLOBAL WARMING bullshit has got to stop.' President Donald Trump
Eccentric and irrational views are, of course, held by many people, but where climate change scepticism happens in Government, it becomes a weapon to thwart environmental protection.
Other measures withdrawn during this same period include 'The Code for Sustainable Homes; subsidies to onshore wind and solar energies; the 'Green Bank' as well as the 'Green Deal' designed to cut the energy loads in existing homes.
All across the board ministries rowed back on environmental initiatives - including the Department of the Environment which cut funding for climate change adaptation by 40%. Owen Patterson DEFRA's then-Secretary of State is a climate change denier.
With a policy environment this toxic, it is little wonder that any serious climate change legislation failed to appear.
After a brief hiatus, housebuilders could breathe again. It was business as usual.
Planning? What Planning?
The relationship between housebuilders and the Government is symbiotic. Both profit from their relationship with each other. A commitment to building homes has been the pledge of governments for over a century. Homeownership is a central plank in most election manifestos, and delivery of such is a key barometer of overall performance; Housebuilders, the other half of the association, have to do what they say on the tin. Their need to build houses correlates almost precisely with Government need to fulfil its promise to the nation. The whole is maintained through a balance applied through the Planning Acts. Local and central governments allow housing and the housebuilders build them. All is fine and dandy just so long as this judicious transaction continues.
Government isn't a commercial enterprise, and housebuilders are not elected institutions. Difficulties occur when the Planning balance is upset by one or other of the parties. It might be on the one hand the need for unusually large numbers (as now) of homes and on the other the Government's need to satisfy the voting public. They see poor quality housing appearing on their green belts and cherished orchards. Added to the mix is the climate crisis as well as other acute environmental issues needing of robust policy to tackle.
Understandably, volume housebuilders resent change and 'unnecessary' legislation. Profit depends on construction efficiency and tight supply margins. Rather like other industrial products, houses are designed as commodities to be sold 'off the shelf'. Template-based rather than custom-built, each is designed to be easily constructed employing simple techniques and conventional materials. Imposed variations including changing legislation and Local Authority requirements invariably threaten the profit margins: new design templates are required, employees need training and the materials supply chain requires adjustment.
The climate crisis has been managed by successive governments according to respective views of the future and associated ideologies. The Labour governments of 1997 - 2010, responding to scientific advice, introduced the Climate Act in 2008. In 2006 they introduced the 'Code for Sustainable Homes' aka the 'Code' or 'CSH' and subsequently committed to the 'Zero Carbon Homes' initiative to be introduced through the Building Regulations in 2016.
The Code evolved from the excellent BRE-developed non-governmental Ecohomes standard. It was designed to encourage an ongoing improvement in performance across a range of environmental issues including energy, materials' impact, water efficiency, waste and pollution.
Use of the Code at Local Authority scale was wholly voluntary. It was implemented using Local Planning to impose aspects of the Code as planning conditions to achieve higher standards in new housing.
Regardless, in response to housebuilders' objections to 'obstructive' planning legislation and 'green taxation,' the Conservative Government progressively cut back Local Authority planning powers to control and direct new housing developments. Included as part of the 'bonfire of red tape' was the Code for Sustainable Homes, withdrawn in 2015.
Don't wait for Whitehall.
However, we try to ignore/deny/avoid it; the elephant in the room is that the climate emergency has been politicised. To an innocent bystander, denial of the threat of climate change is right up there with the 'Flat Earthers' - incomprehensible. However, spend a little time in research, and it's easy to find how the fossil fuel industry and the anti-science movement fund climate denial lobbyists in both the US and the UK. Vested interests on both sides of the Atlantic, bend the debate to a point where progressive policy initiatives are stultified. In the UK, the PM talks in public of combatting shrinking bio-diversity as well as reiterating his predecessors call for de-carbonisation by 2050. Actual action on the ground: policy, legislation, workgroups even, there is none. Government is far the more useful tool in the box when it comes to tackling climate change; It's particularly painful then, to become aware that the current Johnson administration is blunted by ideology and compromised by its sponsors.
Leopards and spots.
Most volume housebuilders have no moral aspirations, so put-away your expectations. They build for profit in the here and now - there is no money to be made from anticipating the future. The only way they change is through legislation or by market forces.
Collective nostalgia throttles design for sustainability.
Developers will continue to build miniature fantasy houses just so long as we buy them. We are complicit in a self-deluding circle of marketing and buying. If the housing sector was the car industry, the lines would still be turning out Morris 1000s and Austin Allegros. Frightened about an uncertain future we hide in nostalgia. Breaking free is difficult.
Generally, we find ourselves in strange times. We’re facing an existential threat more significant and more certain than anything humanity has faced before. In addition to climate change, we simultaneously confront reduced bio-diversity, diminishing resources and environmental pollution. It’s the perfect storm, and we’re still scrambling around to find some way of grappling with it. Ideologues disrupt science; The few technical developments making progress are piecemeal and uncoordinated; Our industries, including construction, are unprepared; Our political systems are ineffective vestiges from a time before environmental crises.
Never have we faced a crisis where lack of effective action by one generation can so completely screw-up the prospects of succeeding generations.
So, what to do?
It’s apposite that one way forward comes from the determination of one Swedish schoolgirl. Frustrated by the lack of political or popular will to confront the climate crisis, Greta Thunberg sat outside the Swedish parliament alongside a sign pronouncing that it was pointless for her to continue her education for a world that she wasn’t going to inherit.
Stripped of the institutions we usually look to for action and reassurance; responsibility falls upon the individual. We must organise ourselves. “Since our leaders are behaving like children, we will have to take the responsibility they should have taken long ago.” (Greta Thunberg addressing COP24, 2018)
We all have roles in the construction industry. Let’s carry out those roles as if our children’s futures depend on them.
About the author
Sandy Patience Dip Arch RIBA is an architect, journalist and speaker. He is the editor of GreenSpec at www.greenspec.co.uk - a site dedicated to delivering information about the design and building of Green Buildings and the Green Self Builder www.thegreenselfbuilder.co.uk a website specifically designed to educate and inform the self-build and custom-build market.
Disclaimer: The views, thoughts, and opinions expressed in the text are solely those of the author and do not necessarily reflect the official policy or position of Ecomerchant, its employee’s or associates. This material is subject to copyright. Reproduction of the material may be made only with the written permission of the author.
"We live in an era when our homes have the potential to be energy efficient, comfortable and affordable places to live, despite ever-increasing fuel prices. In the past, it could be argued that we didn't know how to achieve this but today we have no excuses. Yet, on the whole, we continue to build new houses to a pathetic standard, and our refurbishments commonly concentrate on kitchens and bathrooms, rather than investing to provide warm and pleasant places to live without ruinously high fuel bills." this is an extract from the blog of Ben Adam-Smith a campaigning documentary filmmaker and creator of a film about poor quality building called 'The Future of Housing ' there is a short clip below to help illustrate how poor quality construction can directly affect us all.
There is mounting evidence to suggest that buildings that are being designed to achieve thermal performance standards, including standards set out within the current UK Building Regulations, are in some cases consuming in excess of 70-100% more energy than the predicted values.
Plus, some would say more worryingly, that the Building Regulations do not set an adequate base level of performance and facilitate the delivery of many buildings of poor quality into the UK housing market.
But….don’t blame the Building Regulations they are not designed to deliver quality they are a set of minimum standards, all too often they are described, used and promoted as a benchmark; something to aim for: we must remove the presumption prevalent in the UK that they provide some form of performance guarantee……….they don’t.
The Building Regulations contain 14 individual sections that, in their own words, ‘contain the rules for building work in new and altered buildings to make them safe and accessible and limit waste and environmental damage’ nothing there about quality or performance then.
Within the Building Regulations, Part L is the section on ‘Conservation of Fuel and Power’ which relates to the thermal efficiency/performance of buildings. This is important because it covers the building's potential (target) level of efficiency and therefore comfort, it also has implications for running costs and is linked to (largely erstwhile) carbon reduction targets.
In particular section 43 of Part L deals specifically with a buildings air permeability, or airtightness, recognising this as a major factor in a buildings energy performance Interestingly the word “airtightness” wasn’t even a word used in connection with domestic buildings, until it was introduced and formalised (through building regulations in the early 2000s) and has now become a key part of Part L, section 43 goes on to describe how this the means by which a buildings efficiency can be measured. Compliance with Part L is mandatory throughout the UK it applies to new buildings and certain types of work in existing buildings and is there to enforce minimum standards of energy efficiency.
Airtightness is measured as m3/ (h.m2)@50Pa given as the flow of air (m3/hour) in or out of the building, per square metre of the building internal envelope at a reference pressure of 50 Pascal’s between the inside and outside of the building. Current Building Regulations require 10 m3/ (h.m2)@50Pa, for a new build property, that’s 10 cubic metres of exchanged air per hour at 50 Pascal’s. This is a low standard by anyone’s reckoning, examples of just how bad this is, in reality, are easily found. A new build terraced house with a tested result of 9.1 m3/ (h.m2)@50Pa passes Building Regulations but the tester pointed out (see clip below) that with external wind at an average of 20mph it would take just 6 and a half minutes to exchange all the heated air from within the building resulting in an expected increase in annual heating bills of around 50%.
The short video below is an extract from The Future of Housing which clearly illustrates the point made above, it's well worth a watch, most people who watch this have exactly the same astonished and angry reaction as the owner of the house.
So how do you reduce wastage and increase the energy efficiency of a building, in simple terms insulate well and prevent leakage..... and that sits right at the heart of what needs doing.
In order to arrive at some basic elements that would apply to most building situations, we asked the technical team at Pro Clima if they could come up with a simple list of the “workhorses” of airtightness? Could they find six to eight products that would cover most eventualities? The answer came back as a resounding yes.
First two very pared down observations about airtightness.
- Airtightness is effected on the inside of a building, on the warm or internal side of the insulation; the function is to prevent leakage. Variously called vapour check, vapour barrier, vapour control, or airtight membrane
- Wind and weatherproofing is effected on the outside of a building the function is to prevent adverse weather penetrating the building fabric and reducing the insulation's capacity to perform and prevent deterioration in the building fabric. Variously called vapour control, breather membrane, vapour open membrane, vapour permeable membrane, vapour open underlay and sometimes additionally described as being diffusion open.
Together this ‘wrap’ for the insulated layer allows moisture control geared to our climate with protection from the elements on the outside and leakage prevention on the inside. The airtightness won’t increase the U value of the insulation but it does ensure that the insulation functions to its optimum performance and more likely to achieve designed U Value. It cannot be overemphasised that airtightness and vapour control go hand in hand they work together to solve different problems.
Airtightness means designing and installing a continuous seal around the internal fabric of the external envelope to eliminate unwanted draughts. Once the airtightness layer is in place and sealed with flexible and durable tapes, seals and glues, it ensures that the insulation functions to its optimum performance, saving energy and drastically reducing carbon emissions for the lifetime of the building. The airtight layer also ensures that interstitial condensation risk is minimised, ensuring no structural damage from moisture, mould, rot and damp.
Here is the workhorse list
- Internal airtightness membrane Intello Plus
- External roofing membrane Solitex Plus
- External wall membrane for use with timber frame Solitex Fronta
- Universal jointing tape Tescon Vana
- Sealing tape for windows Tescon Profil
- Sealing tape for masonry and integrating into plaster Contega Solido
Six products that cover pretty much all the basic requirements, there are various accessories such as grommets, stoppers and glue that will be required but the bulk of the work is done with these six products.
How to use these products is neatly described in our “Making Airtightness Simple” [sic] guide available to download here
If you start with the basic principles and keep the products to a proven few then you will be less susceptible to industry ‘noise’ creating confusion or quandary over what product to choose. It would be disingenuous to say the there won’t be times when technical advice is be needed and that is easily available through our technical support team. What it does mean is that for those manufacturers who do it well and make it look simple, take them on trust you are benefiting from years of robust and thorough testing and R&D arriving at a proven and purpose specific product. Their expertise should be your comfort.
Our thanks to Ben Adam-Smith at Regen Media for his quotes and permission to use a clip from the programme see the whole film by clicking here
 Lessons from Stamford Brook, Understanding the Gap between Designed and Real Performance, Evaluating The Impact Of An Enhanced Energy Performance Standard On Load-Bearing Masonry Domestic Construction, Partners in Innovation Project: CI 39/3/663, Report Number 8 – Final Report, Leeds Metropolitan University
 DCLG Policy paper 2010 to 2015 government policy: building regulation
 Check local variations for Scotland, Wales & Northern Ireland
 The Future of Housing Paul Jennings 2016
What is Sustainability?
The most commonly accepted definition of ‘Sustainability’ was made in 1987 when referring to future world development: ‘Sustainable development is 'development that meets the needs of the present without compromising the ability of future generations to meet their own needs’. The concept of ‘Sustainability’ in practice is a broad church within which a number of social, economic and environmental issues are included.
The building industry is usually responsible for around 10% of the UK economy and so represents a significant impact on areas of sustainability. The industry’s key zones of accountability are: Global warming gases from the energy it uses; The quantity of material resources it extracts from the earth; The environmental damage caused by material extraction, processing and construction; And the damage to health caused throughout the extraction, manufacture, use and final disposal of building materials.
How does the building industry achieve higher levels of sustainability?
The industry can be more sustainable by adopting better principles and practices in the way it designs and constructs buildings. The way we design and build using the principles of ‘Green Building ‘can make a significant contribution, not only to reducing our collective impact on the environment but also to our health and wellbeing in the places we work and the homes we live in.
Like many other large industries, construction is very slow to change. Economically, the industry is notoriously volatile, so it’s no surprise that change is seldom welcome or implemented. Most change is legislation-led through the Building Regulations and industry-related initiatives such as BREEAM; but some change is thanks to individuals and companies taking responsibility for reducing their own environmental impacts.
Sustainability, Quality and Self Build
The core of the construction industry is the ‘volume’ house-building sector. So critical is the role of the dozen or so companies that make up this group, that their economic role in the GDP (Gross Domestic Product), is regularly cited in economic reporting as the ‘weather vane’ of all industry. Key to their success is their efficiency of production. They buy materials and erect and sell homes on an industrial basis that maximises profits. That they manage to do this, whilst actually selling arguably poorly performing, indifferently constructed houses with abysmal space standards, is thanks to a well-oiled marketing machine that consistently succeeds at selling a premium on image, location and affordability. Notably, when the national economic output is bleak, so is that of the builders, who stop building until recovery. This chronic ‘boom and bust’ approach to housing is one of the reasons that the UK fails to meet the need for more homes.
In stark contrast to the anonymity and indifference of industry-produced housing, the self-build/custom build sector delivers for its members, well-built, well-performing, high quality and spacious homes. Increasingly their houses are made from materials and designs that put people, their health and their future at the centre of the process.
There are between 10 - 20,000 self-builds in the UK every year. This is less than 10-15% of all the homes built annually but may constitute as much as one-third of new detached homes - this compares with 60% in Germany and 80% in Austria where self-build is the norm.
Despite their number, self-builders have and continue to make significant contributions to advances in house design and technology. In particular, in recent years, they have been responsible for the dramatic uptake of ‘Green’ features such as renewable energy and low environmental impact building systems. Outside of the self-build market, these are features that take several years to filter through to commercial housing developments.
There is many a volume house builder who looks upon his self-build cousin with envy. Shorn of the profit motive, but instead equipped with a will to build exactly for his/her needs, the self-builder is at liberty to choose the type of construction and the materials that the building is made from. In particular, the self-builder is uniquely enabled to choose freely from the wealth of materials now appearing on the market that are not only of very high quality but also representative of a quickly growing market in the UK for ‘sustainable’ and healthy ‘Green’ products.
As part of the UK government’s first initiative in 2006 to tackle climate change, it published a voluntary code requiring new homes to add renewable energy devices to the buildings. That it kicked off thousands of new businesses dealing in the installation of wind turbines, heat pumps and solar panels was probably no bad thing, but it was responsible for sending house builders off in the wrong direction.
Critics soon pointed out that the adding of energy-generating technology was usually doing not much more than covering for the poorly performing buildings they were attached to. The analogy to the policy was that of a leaking bucket of water: to keep the bucket full, it was necessary to keep pouring water into it - rather than fix the leaks themselves.
The code didn’t change and was eventually eclipsed and abandoned. Instead, building designers and developers worked towards design standards of their own adoption. The most well-known standard, imported from Germany, is the Passivhaus standard which ensures that the way a house is built will deliver a heating requirement of no more than 15 kWh/m2/yr. This very low figure is achieved by careful design and the building fabric alone. For many already built Passivhaus homes, their heating systems have become largely redundant.
This emerging (in the UK) methodology of designing buildings to reduce their energy usage through building technology rather than adding renewable energy systems is known as ‘Fabric first’.
Characteristics of a ‘Fabric first’ approach is:
- High performance and high quantities of insulation.
- Maximum levels of air-tightness.
- Use of heat given off by the occupants and their cooking and electronic devices to help the heat the spaces.
- Optimisation of natural ventilation.
- Optimisation of solar gain through appropriately located windows.
- Sometimes using the thermal mass of the building to absorb excess heat.
In addition to high degrees of energy efficiency, the ‘Fabric first’ method provides a comfortable environment that makes few demands of the building’s occupants. Where renewable technologies place the reliance on the occupier to operate the sometimes complicated controls, a well-built energy efficient building has already done all the work for them.
What to look for when choosing ‘Green’ building materials
‘Green’ building materials are products that have a lesser environmental impact than other materials that might be used for the same ‘job’ in the building. Apart from environmental preferences, Green materials are also usually associated with high levels of performance and safe user-friendliness.
Of course, not all the building materials we employ have significant damaging effects on the environment. Those that do vary from severe to mild and to sort one from the other it’s useful to consult the GreenSpec website which provides information about the environmental impacts of materials at www.greenspec.co.uk
There are usually plenty of alternatives, but the golden rule is to ensure that the products eventually selected can do the job demanded of them in a way equal to or better than materials they’re replacing.
It is notoriously difficult to clearly identify materials with a lesser overall environmental impact. Experts can take a lot of time in examining and assessing the potentially wide range of environmental properties contained within even a single building product.
However, when specifying an appropriate product or material, these are some of the key low impact and beneficial aspects to look for:
- Products that perform well and are easy to build with
- Materials made from renewable crops such as timber, wool or hemp.
- Products manufactured from abundant resources such as lime, clay or rock.
- Products which minimise the use of fossil-fuel energy in the manufacturing process (embodied carbon).
- Materials which, as a part of their function, improve a building’s energy efficiency.
- Manufacturing processes that don’t pollute.
- Materials that are safe to use and dispose of or recycle.
- Products containing recycled materials.
The Healthy Home
Whether it be sleeping, eating, relaxing or working, we spend most of our day inhabiting our homes. Because of that time in a familiar space, we become adept at managing its environment. We are familiar with controlling lighting, heating and ventilation through simply throwing a switch or opening a window. Though the technologies have changed, the basic control actions are as they have been for generations.
Though the basic provision of light and warmth is unchanged, the contents of the air we breathe has altered over the last 50 years. We could now be dealing with a raft of possible toxins that if not sufficiently designed and built to avoid, could lead to serious health issues. Perhaps not surprisingly, these changes have been brought about through the way we build and the materials we use.
The principal drivers behind the need to improve the efficiency of our homes began with the oil crisis in the 1970s since when we have set out to reduce our dependence on fossil fuels. In the last decade, climate change has been added to the agenda. The combination of the two has had an aggrandising effect on building regulations and the techniques we use to design and build.
For our homes, the two main methods of addressing energy conservation are insulation and airtightness. We are used to using insulation in our walls and roofs, but now house builders have to learn the techniques of sealing openings in the building fabric to prevent warm air leaking out.
The result of sealing buildings could be that for many of us opening a window or just relying on the leaky nature of our buildings might not be enough to deal with the smelly, oxygen-depleted or damp air caused by everyday living.
Air contamination from materials we use in our homes is relatively new and owes its occurrence to the growth of synthetic materials. Ordinary products such as paints, floor finishes, timber-laminates, furniture, synthetic textiles, plastics and foams can emit a chemical cocktail including volatile organic compounds (VOC’s) like formaldehyde, xylene, isobutylaldehyde, and organochlorides, aldehydes and phenols. Emissions from materials are known as ‘off-gassing’ and can result in higher, more toxic concentrations without suitable ventilation.
Sadly the most familiar aspect of an unhealthy building, damp caused by condensation, continues to blight modern housing. Most buildings show the effects of condensation to some degree – from water appearing on the glass of cold windows through to damaging mould found on walls and ceilings.
Asthma linked to inhabiting in these unhealthy conditions is on the increase, caused by damp and mould, house dust mites and chemicals in carpets and flooring materials.
The direct solution to damp air is adequate ventilation, but there is also a technique of building that has gained traction in recent years. The ‘Breathing wall’ is one that uses ‘hydroscopic’ materials and membranes together to allow moisture to pass from the interior through the wall to the outside air.
Summing-up, improving indoor air quality (IAQ) is achieved by:
- Designing a ventilation strategy that can include simply opening windows through to providing mechanical ventilation. Above all, whatever strategy is chosen, it is vital that it is easy to understand and operate by the user.
- Considering the use of ‘breathing walls’ that help migrate internal dampness through to the outside.
- Avoiding materials that are suspected of off-gassing toxins.
- Thinking holistically about combining techniques of reducing humidity and pollution and toxins - adding up to a whole that is more effective than the sum of its parts.
- Using Green building materials from suppliers like Ecomerchant.
… and not forgetting the potential of indoor plants to absorb toxins and carbon dioxide
Top Tips For Going Green
Whether planning to build new from scratch or refurbishing, this is the time to incorporate sustainability into your project through design and the careful choice of materials; Getting it right will insulate you against spiralling energy bills, provide a durable long lasting healthy home and leave a lighter footprint on the earth.
The building industry generally acknowledges that self-builders build better quality buildings; In building their own homes, they are often keen to explore proven and beneficial systems that would not necessarily be part of a developer or volume house builder’s package.
So what are the key aspects of building to green standards?
- Using enough insulation - most buildings are built with too little
The more insulation you incorporate into the walls, roofs and floors of your home, the more heat it will retain. Insulation is probably the main element to get right at the start, so it’s important to ensure the appropriate materials are used in the right way and in sufficient quantity.
- Design-in airtightness and ventilation – ‘Build tight, ventilate right’
Fewer gaps in your home’s structural envelope mean less heat lost. Good air tightness maximises the efficiency of the insulation and reduces fuel bills. With airtightness, ventilation is essential and needs careful design. Ventilation can be passive, mechanical or both.
- Use the buildings thermal mass to best effect
The idea of thermal-mass is difficult to understand for most of us – so it’s wise to get advice before using it. Materials such as stone, brick, terracotta and concrete can provide 'thermal mass'. Used with care, it can help moderate the internal environment throughout the day by absorbing excess heat from the sun or other sources and then releasing the heat back into the interior during darkness.
- Design for overheating.
Increasingly hot summers are a climate feature we all need to design for. Use wood fibre insulation, particularly in rooms in the roof, but also in walls to slow down heat transfer from the outside. Think about using shading for windows exposed to the sun in summer, but make sure they’re not shaded in winter.
- Make the best use of natural light
Maximising the amount of natural light in your home reduces the need for artificial lighting. Windows are an essential element of the building's performance. Modern windows can be very efficient with whole window U values as low as 0.8W/m2K. 'Solar gain' can help heat the home.
- Choose Green materials
Green materials have a range of features and benefits not usually present in synthetic materials; A majority are less polluting, safer and recyclable. Most too can significantly out-perform synthetic oil-based products in aspects that are becoming more important as the UK warms-up.
- Structural systems - choose your system early in the design process
Most construction techniques can be adapted to meet high levels of energy efficiency, but some lend themselves more immediately to hitting the highest standards. This is where you will come across the expression ‘Fabric first ‘where the building contributes significantly to overall energy efficiency.
Some of the most popular systems for self-builders are:
- Timber frame with timber, brick or render cladding
- Monolithic clay blocks and render
- Brick and block cavity walling
- Cross-laminated timber (CLT) and cladding
- Deploy renewable technologies only after your shell design is complete
Self-builders have led the way in terms of adopting renewable technologies to best effect, the golden rule here is to design the building to do the work, then match your energy needs to that level.
Thanks to our authors Sandy Patience & Will Kirkman: Sandy is an architect, journalist and speaker. He is the editor of GreenSpec at www.greenspec.co.uk - a site dedicated to delivering information about the design and building of Green Buildings. Will is a co-owner of Ecomerchant (a sustainable builder’s merchant), writer and speaker and has been involved in promoting green construction for over 25 years.