Esprit d’escalier: the wit and symbolism of the staircase

What is it that fascinates us so much about staircases? More symbolically rich than any other building element, the staircase gives rise to a multitude of associations.

The staircase is a place of fleeting conversations, chance meetings, contrived accidents, secret assignations, ghostly encounters, lost opportunities for witty responses, and a symbol of lofty ambition.

It can be a descent into the underworld (‘Abandon all hope, ye who enter here’) or a Jacob’s ladder leading into heaven.

Do you dream about going up or down stairs? It could mean that you are coming to a decision on a complicated issue… The bottom of the stairs represents your current reality; the top landing is the conclusion for which you strive.

Any budding guitarist, of course, will attempt to learn the inevitable ‘Stairway to Heaven’ intro. (The bane of many a music store.)

There is even a page on Pinterest entirely dedicated to ‘Wonderful stairways and staircases‘.

For photographers, staircases are a constant source of inspiration. When viewed from above or below, the stairway takes on a purely graphic, geometric quality – like an abstract pattern rather than a physical object.

Out of self-indulgence, I thought I would share with you some of my favourite images of stairs and steps – below.

In the meantime – if you need to find, compare and select staircases, balustrades and handrails, ESI.info is a good place to start:

• Staircases
• Balustrades and balconies
• Handrails
• Wall protection handrails

Imminent launch of the new Kingspan Potton show house

With just a month to go until Kingspan Potton launches its new show house, the finishing touches are now being added. This includes the installation of Sunfold Systems’ internal door sets. In this guest post, Sunfold’s Sarah Maginn explains how the company’s products will help achieve the project’s CSH level 4 target.

As a folding door specialist, Sunfold Systems started the first leg of its door and window installation at the new ultra energy efficient show house in St Neots back in November last year. Working alongside a number of high-quality suppliers such as Mitsubishi, Nu-Heat, Thinking Bricks and Allergy Plus; Sunfold Systems has supplied its own range of thermally efficient products to help Potton achieve its sustainability target.

The Potton show house, which is officially launched at the beginning of May, has been designed as a contemporary barn to exceed the requirements for level 4 of the Code for Sustainable Homes (CSH); an initiative that was launched to ensure that all new homes constructed in England and Wales can be described as zero-carbon by 2016. The show house, when fully functioning, will demonstrate the key ways to achieve the Code by meeting the sustainability requirements of a new home measured against nine design categories – such as energy and CO2 emissions, pollution and waste.

First to be installed from the Sunfold range were the SFCW window systems. These were fitted as part of the first fix back in in November, and consist of an aluminium and timber combination frame that holds excellent U-values. The exterior doors were fitted at the beginning of February, including a four-panel aluminium bi-folding door set using the SFK70 aluminium system as well as a mid-range SFK20:20 three-panel bi-fold set. The Antelli front door with a high-insulating core accompanied by side and top lights followed shortly after and, as I type, internal door sets are being fitted ready for project completion.

Now that the scaffolding has been removed, onlookers can truly see the beauty of the self-build project, which will be completed in the coming weeks and officially launched to the public on the 8th May 2012. The barn – which has been designed for open-plan, spacious living with natural light flooding through the windows and bi-folding doors – will, once finished, house a number of advanced sustainable characteristics to create not only a lovely example of living space but also the energy efficiency that can be achieved by such a home.

Project manager Brent Ackerman commented: “The aim was to make the property as thermally efficient and air-tight as possible in order to achieve the credits required for the Code for Sustainable Homes. The brickwork on the outside of the barn has been finished, the landscaping is now well underway, the bathrooms and kitchen are in place and decoration is almost complete. Once finished, we will really be able to see the spacious interior of this barn-style home.”

You will find further information on Sunfold Systems’ ranges on ESI.info, where products and systems can be compared side-by-side. Potton self-build is active on Twitter, as is the Sunfold Group.

The great PV break-through

Ross McGuinness is Area Sales Manager for Kingspan Insulate and Generate. In this guest post, he celebrates the unprecedented take-up of solar PV, but warns it’s too early to break out the Champagne just yet…

The massive expansion of solar PV capacity in the UK has passed another milestone recently. Just a couple of weeks ago, SPV broke through the symbolic barrier of 1,000MW of installed capacity.

Sunset reflected in a solar panel, by ToGa Wanderings on Flickr

This growth has been rapid: in April 2010 there was a mere 26MW installed nationally. 23 months down the line and the industry has topped 1GW, which is a stunning result. The driver behind this seismic shift towards green, renewable energy is without a doubt the government-backed Feed-in Tariff (FiT).

This is all very positive news, and with the announcement from the Department of Energy and Climate Change some weeks ago stating their wish to have 22GW installed by 2020, you could be forgiven for thinking that everything is rosy in the SPV garden.

This announcement of several weeks ago has set out something of a roadmap for PV, but key questions need to be addressed before the industry will come out and support the new policy.

The government has destroyed any trust it may have had with the sector and it will take quite some time to repair what has become a fractious relationship. Continued court actions and appeals mean that, in the short term at least, a cloud hangs over SPV in the UK right now.

Looking at what is proposed by government, many industry insiders believe that it will be challenging to convince consumers to invest in SPV at the new rates. One of the main drivers of SPV has been the willingness of investment firms to “fund” SPV, hence the plethora of “free” installs whereby the end user got the benefit of free or discounted electricity and the funder got the Feed-in Tariff.

The new FiT rates will make it unlikely that similar funding models would be viable from an investor perspective. Funders look for an IRR of a minimum return of 7%; anything less and they simply go elsewhere for their fix. The government is on record as stating that they envisage returns of ca. 5% and will strive to ensure they do not go any higher by linking the price of PV modules to the FiT rate.

On the face of it this is a good proposal and should go some way to preventing the “Boom and Bust” that has beleaguered the industry. The mechanism has the potential to provide a sustainable and controlled future for the FiT.

In the long term, this is a positive for the industry, but short term – bearing in mind the skepticism and mistrust about the government’s attitude, and also bearing in mind the further cuts announced for July – you can understand why many are not cracking out the champagne just yet.

Solar panels in a low-tech setting: Breckenridge, Colorado

The belief is that Westminster is out of touch with where the industry is at, but most crucially and disappointingly, they fail to see where the industry can go. The Minister of State for Energy and Climate Change tweeted a couple of weeks ago that the Germans had just announced big cuts to their FiT scheme, implying that he was actually correct in pursuing the cuts here – blissfully ignoring the fact that Germany has had a Feed-in Tariff for the past decade, has a total installed capacity close on 25GW and operates on a completely different scale to the UK.

Under the new rates, the German government is proposing to pay €0.135/kWh for ground-mounted solar farms with a capacity of 10MW or less, and for rooftop installations that are 1–10MW in size. Germany is lightyears ahead of what is currently viable in this country.

There are, however, some reasons to be optimistic. The Chinese government last week directed the leading polysilicon and solar cell manufacturers to increase production, which should see prices continue to fall. That’s good news for consumers and probably bad news for non-Chinese manufacturers. China really does seem to be attempting to establish itself as the SPV equivalent of the Middle East. Continued downward pressure on price of SPV definitely looks set to continue in the short-to-medium term.

The great PV breakthrough should achieve one thing, however: SPV will at least now receive the recognition it deserves as a viable and high-quality alternative to fossil fuels. The SPV industry deserves recognition in Government energy strategy.

There is simply no reason why, if there is willingness on behalf of the powers that be, that by 2020 the UK cannot have the 22GW of solar capacity that government says it wishes to have.

Ross McGuinness, Area Sales Manager, Kingspan Insulate and Generate

Twitter: @rossmcguinness   Email: ross.mcguinness@kingspan.com

Spotlight on solar air heating

Andrew Brewster leads the Renewables Design Team for the CA Group – a specialist building envelope manufacturer and installer. In this guest post, he puts one of the lesser-known solar technologies under the spotlight:

Solar air heating is a proven technology that has been developed specifically for heating large spaces. With high-profile advocates including The Royal Mail, Marks & Spencer and Jaguar Land Rover, the technology is increasingly expected to become part of the sustainability strategy of those companies leading the charge for environmental responsibility.

Harnessing sunrays to heat large spaces

What is solar air heating?
Solar air heating works by harnessing the sun’s energy via a Transpired Solar Collector (TSC), or SolarWall®. The SolarWall® technology pre-heats fresh, outside air, which is then actively drawn into the building’s heating system, contributing considerably to a reduction in the need for fossil fuels.

The technology is 100% renewable and has the effect of dramatically reducing a building’s overall heating requirement, providing significant savings in energy consumption and carbon emissions.

SolarWall® in action
CA Group recently installed the world’s largest SolarWall® on a single building for Marks & Spencer, at the retail giant’s 80,000m² East Midlands Distribution Centre (EMDC) in Castle Donington. The 4,500m² Transpired Solar Collector is expected to reduce the building’s heating requirement by somewhere in the region of 30%, by generating more than 1,135,000kWh and saving over 256t of CO2 per annum.

The SolarWall® can be seen in action at the Jaguar Land Rover training academy in this video:

The benefits
The revolutionary solar air heating system has the lowest capital cost and the highest known efficiency of any active solar technology in the world (up to 80%), generating in excess of 500 Watts of thermal energy per square meter on a clear day [Dr. Chuck Keutcher, U.S. National Renewable Energy Laboratory (NREL)].

It also offers the quickest return on investment, with an estimated payback period of three years on new build and eight years on retrofit applications. So as well as being an excellent option from an environmental perspective, it is also one that makes good commercial sense.

Global recognition
SolarWall® has been available for almost 30 years and is used in over 35 countries globally. A number of companies have tried to emulate the system but, due to a lack of understanding and third-party testing, they have been unable to replicate SolarWall®’s level of system performance.

In the UK, as part of its ongoing development and accreditation, the technology has received the independent endorsement of five leading authorities: Oxford Brookes University, the Welsh Assembly, Cardiff University, BSRIA and BRE.

CA Group has seen a significant uptake in the technology because of the very tangible results it delivers. As awareness of the technology’s capabilities increase, the Group anticipates that solar air heating will become part of the sustainability strategy of more and more companies looking for cost-effective ways of making the biggest impact on their CO2 emissions.

CA Group’s interactive Renewables Guide offers further information on solar air heating and other renewable options geared towards the generation of power and heat for commercial, industrial and distribution centres.

• Find out more by downloading a copy of the CA Group’s Renewables Guide.
• Find, select and compare solar energy products on ESI.info.

Green covers from Down Under: an Australian designer’s summary of green roofs

Our ‘Australian Correspondent’, Mark Iscaro of First Angle, is in the process of specifying a green roof for a client’s building. In this guest post, he takes a closer look at the concept, components and benefits of living roofs.

San Francisco Academy of Sciences, by Osbornb on Flickr

“This blog will be focusing on a new Green Building initiative in Australia that is slowly making its way into the mainstream. Currently a growing trend around the world, the idea of having a green roof is gradually catching on. Even one of my own clients has finally given in and allowed me to put a green roof on their new building in Marysville.

So what is a green roof?

A green roof is a partially or completely covered roof containing a growing medium and vegetation. These are positioned over a waterproofing membrane and can include water retention, drainage and irrigation systems. There are two main forms of green roofing available in Australia: intensive and extensive, the difference being as follows:

1. Intensive roofs (roof gardens) contain over 300mm of plant growth and can include a wide variety of shrubs, grasses, tree species and even kitchen herbs. They are also more akin to a park or garden, with easy access for recreational purposes.
2. Extensive roofs contain less than 300mm of growing media, and so are generally lighter in weight. They are suitable for harsher growing conditions and require minimal irrigation, using hardy, low-growing plant and ground-cover species. These roofs can handle slopes up to 30°. Extensive roofs are usually only accessed for maintenance.

Commercial green roof installation, by Arlington County on Flickr

What are the benefits of green roofs?
• Reduce heating (by adding mass and thermal resistance value).
• Reduce cooling loads on a building by 50 to 90% (by evaporative cooling), especially if it is glassed in so as to act as a terrarium and passive solar heat reservoir: a concentration of green roofs in an urban area can even reduce the city’s average temperatures during the summer.
• Reduce stormwater run-off.
• Natural habitat creation, promoting biodiversity.
• Filter pollutants and carbon dioxide out of the air, which helps lower rates of diseases like asthma.
• Filter pollutants and heavy metals out of rainwater.
• Help to insulate a building for sound: the soil serves to block lower frequencies and the plants block higher frequencies.
• Increase agricultural space.

So now that you know a bit more about these wonderful creations and the benefits they provide, why not look at one for either your current home or perhaps your next project?

Note: Information was gathered from Wikipedia & Green Roof Technologies.”

Mark is active on Twitter, and details of his projects can be found on the First Angle design and planning website.

For more facts and figures on green roofs in the Southern hemisphere, Green Roofs Australasia is worth a visit. A good variety of extensive, intensive, semi-intensive and brown/biodiverse roofs can also be compared over at ESI.info. If you are looking to plant a facade rather than a roof, have a look at what’s available in terms of living walls and vertical gardens.

Fractals in architecture: good for the soul?

What comes into your mind when you hear the word ‘fractals’? Maths and geometry lessons? Swirly spirals in cosmic colour-schemes on student bedsit walls? Self-similar shapes in nature, like snowflakes, ferns and broccoli? The drip-paintings of Jackson Pollock?

Wikipedia says a fractal is “a rough or fragmented geometric shape that can be split into parts, each of which is (at least approximately) a reduced-size copy of the whole”.

Fractal architecture is generated by the application of fractal geometric principles to the design of facades and building forms. Here are some examples of fractal architectural facades.

Yannick Joye, from Belgium’s Ghent University, argues that this type of geometry has been used in architecture for two main reasons:

1. Fractal rhythms, created by midpoint displacement, are used as a creative tool to generate a variety of architectural components, such as planning grids, strip windows, noise abatements etc. Examples can be found throughout architectural history, from Doric entablatures to modern facades.

2. The typical measurement techniques of fractal geometry are used to analyse the structure of buildings. The box-counting dimension, for example, is a measure for the recursivity of detail on ever smaller scales. An extract from Joye’s Fractal Architecture Could Be Good for You:

Carl Bovill [1996] has applied this method to different building styles. He found that Wright’s organic architecture shows a ‘cascade of detail’ on different scales, while in Le Corbusier’s modernist architecture, the box counting dimension quickly drops to 1 for smaller scales. This finding is consistent with the fact that ‘Wright’s organic architecture called for materials to be used in a way that captured nature’s complexity and order … [while] Le Corbusier’s purism called for materials to be used in a more industrial way, always looking for efficiency and purity of use’.

In the following illustrations, forms like arches and domes reoccur on different hierarchical scales throughout a Hindu temple, the Stadhuis (Town Hall) in Bruges, and the Notre Dame de Paris.

Stadhuis, Bruges

Notre Dame de Paris

However, as satisfying as fractal geometry may be to mathematicians, Yannick Joye is more interested in a less visible side-effect of fractal architecture. From an aesthetic point of view, Joye (whose specialist field is philosophy) points to research showing that human beings are innately attracted to fractals, that fractal shapes and images have a calming effect on us, and that this affinity may be related to our long-ago habitat – the trees:

… as a result of evolution, the brain has a preference for fractal structures, and feels relaxed when surrounded by these. This means that one of the reasons why we like the fractals in Gothic and Hindu architecture is that they remind us of our ancient, natural habitats. Because our brains have not fundamentally changed since prehistory, these biofilic responses are still at work.

A classic example of fractals in nature: the fern (Freefoto.com)

Do you see fractal architecture as calming and harmonious, or do you have more of a Euclidean frame of mind? I would love to see examples of the buildings that appeal to you the most.

Shadows through sand: translucent concrete

Concrete may have started out as a heavy, low-tech material, associated with architectural brutalism and 1960s high-rises. How times have changed… Already on the market, or half-way towards becoming commercially available, are concrete formulations with any number of surprising qualities.

Silhouette & sand dunes, by Daniel Oines on Flickr

These days, concrete can be lightweight, waterproof, recyclable, bendable, self-healing, and even (arguably) environmentally sound. And now, concrete – that most solid-sounding of building materials – can be translucent, too.

Here is how light-transmitting concrete is made: layer upon layer, ultrafine optical fibres are paralellised and distributed through a fine-grained concrete mix. When set, the concrete is cut and shaped into panels or tiles, which are then polished to the desired texture.

With structural performance indicators including a compressive strength of 49N/mm2 (MPa) and bending strength of 7.7N/mm2 (MPa), translucent concrete may be used as a load-bearing material.

Luccon concrete, supplied by NY Stone Manhattan (on interiordesign.net)

When used as part of an external wall or placed in front of a window, these concrete panels need no light source other than the natural daylight that is diffused through the solid surface. If the concrete is mounted internally in the shape of wall, floor or ceiling panels, artificial light sources can be used to create special effects.

As you can imagine, designers have started playing around with this concept and its various applications:

• The optical fibres, backlit with coloured LEDs, create concrete walls that shimmer in different shades according to where you stand in a room.
• Points of optical fibres in different diameters, distributed unevenly through a dark concrete panel, create the illusion of a starry night sky.
• The light-transmitting fibres can be arranged into the shapes of logos, company names, symbols and signage.

Two companies involved in the development, manufacture and supply of translucent concrete:

LUCEM Lichtbeton

LUCEM LABEL tiles with custom logos, names and icons

LUCEM bar counter with coloured background lighting

LiTraCon™

Main entrance of Museum Cella Septichora, Hungary

Iberville Parish Veterans Memorial, Baton Rouge

More information can be found in this Gizmag article on light-transmitting concrete. And finally, here’s one that DIY’er Calvin Drews made earlier: a video on how to make your own light-transmitting concrete.

• Get the low-down on preblended concrete on ESI.info

300 years of brick-making: the Chailey kiln

In a world of mass-production and building products whose inherent sustainability is lost in the amount of air, sea or road-miles it takes to get them to site, it is (at the risk of sounding a little bit Luddite) comforting to know that some products have been made in the same way, in the same place, for centuries.

In 2011, the Chailey brick factory in the middle of the Sussex Weald (owned by Ibstock since 1996) celebrated 300 years of continuous, traditional brick-making.

The Chailey clamp in operation at night

Bricks from the Chailey kiln are still produced to an original recipe, which includes a blend of local Wealden clays from Ibstock’s own quarry. The stock bricks are fired in a traditional clamp (one of only three still in use in the UK), giving them distinctive textures and warm colours. All Chailey bricks are then sorted and packed by hand – although the craftsmen and stackers do not, presumably, wear this traditional garb every day:

Ibstock stackers at the Chailey site

Clay pipes, tiles, pottery and bricks have been made in and around South Chailey since 1711. Since 1792, successive generations of the Norman family owned and operated the factory until it was finally sold to Redland in 1959.

The Chailey factory has the capacity to manufacture approximately 14 million bricks per year using a soft mud moulding process. It also manufactures pavers and brick specials. This video on Ibstock’s website details the history of the Chailey site and shows the traditional, clamp-fired production process.

The fire hole at Chailey

The Bulmer Brick & Tile Co – specialists in purpose-made bricks for restoration and conservation projects – also make their bricks in accordance with time-honoured methods. Fired in a coal-burning down-draught kiln, their facings, rubbers and specials are made from London clays that have been dug from these Suffolk seams in a near-continuous line since Tudor times.

The Minter family: skills handed down through generations

Another building product largely unchanged through time is the traditional plain roofing tile, which has been made to a standard size since 1666 (when the Great Fire of London gave rise to product standards and building regulations). Historically – and for obvious reasons – factories for making bricks and tiles were sited right where the clay source occurred, and that’s where they remain.

Image by Hotblack on MorgueFile

• View Ibstock’s product range on ESI.info
• Browse and compare roof tiles on ESI.info
• Find out about Bulmer’s specialist brick cutting service, or read about the company’s history on the BBC website

The relative sustainability of building materials – guides and sources

The trade associations, enthusiasts and lobbyists for different building materials are busy telling us how sustainable their material of choice is, and how it out-performs all others. Amongst the myriad claims, facts and figures, how can we establish which material is the most environmentally friendly?  And is that even the right question to ask?

Timber is a natural material and absorbs CO2 while it grows, steel is eminently recyclable, concrete is ideal for thermal mass construction, whereas bricks are durable and can be reclaimed.

Even if we discover which has the lowest embodied carbon, for example, we may not agree on what sustainability actually means. Are we talking about cradle-to-grave lifespans, economic viability, wildlife considerations, energy performance, aesthetic impact, recyclability – or even taking a holistic view of the building’s use and social sustainability within a local community?

In the absence of a unified framework of assessment and an agreement on relevant metrics, the debate will continue.

At the end of the day, each project needs its own, tailored assessment. A good designer will select from all options and choose what is fit for purpose, rather than become too attached – by habit or preference – to one material or another.

But in order to make that choice, we need a level-headed view of the facts available for each material, accompanied by real-life case studies. We also need to consult with people who are in the know about the different accreditations and codes, and can give an unbiased overview. Below are some sources that make a good start.

Codes and certifications: consultancy

• Mel Starrs, Associate Director at PRP Architects, specialises in sustainability and green buildings. Her Elemental blog is full of useful information.
• The CodeStore.co.uk has a directory of CSH consultants and assessors. Materials is number 3 on the Code’s list of 9 sustainable design criteria.
• Jennifer Hardi works for the BRE’s Low Carbon Future team and is also part of the technical support team for the Energy Saving Trust’s Best Practice Helpline.
• Bruno Miglio is a Leader of Global Materials Science at Arup. The team offers advice on the use of materials in engineering and architecture – from design to reuse or demolition.
• The BRE’s Green Guide to Specification assesses building materials and components in terms of their environmental impact across their entire life cycle.

Concrete

This is Concrete showcases sustainable construction projects and encourages project-based feedback, presenting case study evidence to support the sustainability credentials of concrete.

Sustainable Concrete has information on concrete production, performance and end-use, and provides indicators on materials efficiency.

MPA (Mineral Products Association) runs the Concrete Centre, which contains news, publications, webcasts, online services, advice and design tools.

Steel

The BCSA is the national organisation for the steel construction industry. Its website, SteelConstruction.org, has a section dedicated to sustainability. The BCSA’s Target Zero project “will generate costed solutions for structural steel framed construction that achieves highest BREEAM ratings and changes to Part L of the Building Regulations, meeting emissions reduction targets towards zero carbon by 2019.”

Timber

TRADA has a library of downloads that detail the sustainability of timber. The Association’s Technology Assessed scheme also helps establish whether a company’s literature gives a fair representation of the benefits and characteristics of a product or service – a useful tool against greenwash.

The Forestry Commission also provides comprehensive facts and figures on the timber trade.

Stone

All members of the Stone Federation of Great Britain have to comply with this Sustainability Statement. The Federation provides a Technical Advice Service for the commercial and domestic use of natural stone.

Stephen Critchley – a Master Stonemason in Central London – is a font of knowledge on ancient and modern uses of natural stone, giving talks, workshops and demonstrations.

The simplest view of the sustainability of natural stone – there is tonnes of it about and it lasts for a very long time – is outlined here by CED.

Bricks and blocks

Bricks, in the words of the Brick Development Association, are “a versatile and durable building material, with excellent life cycle performance, energy efficiency, high thermal mass and responsible manufacturing.” Its publications on the sustainability issues of bricks and brickwork are listed here.

Sustainable Build details the manufacture and use of bricks as a sustainable building material in this article, and also comments on stone vs brick.

What other sources have you found useful for determining the sustainability of specific building materials? Please leave a comment and let me know!

This post was inspired by an interesting conversation on Twitter with structural engineers David Sharpe and James Thomson.

Compare and select building materials on ESI.info

• Preblended concrete
• Structural and joinery timber
• Timber beams and joists
• Bricks
• Building blocks
• Building and walling stone
• Stone quarries
• Steel beams and columns

PassivHaus: the devil is in the detail

The PassivHaus concept is quite a simple one: create an airtight, super-insulated structure, install mechanical ventilation with heat recovery, address thermal bridging, and find yourself with a building that can essentially be heated by a hairdryer. However, as with most things, the devil is in the detail…

Here, I take a look at the following questions:

• What does a PassivHaus look like?
• What does a PassivHaus cost?
• What about air quality?
• Which products are used in a PassivHaus?
• What is it like like to live in a PassivHaus?
• What is the next big thing after PassivHaus?

What does a PassivHaus look like?

PassivHaus is really a design and build process, as opposed to a particular style of architecture. Whilst we may have preconceived ideas of a PassivHaus-certified building’s aesthetics, it could (at least in theory) look pretty much like anything – especially given that existing buildings can be retrofitted to PassivHaus standard.

100 Princedale Rd, Paul Davis + Partners

This was done at 100 Princedale Road – a Victorian house in a London conservation area – by Paul Davis + Partners and contractor Philip Proffit of Ryder Strategies Europe Ltd. This house was the first of its kind in the UK to achieve PassivHaus accreditation, meeting its target to reduce carbon emissions by 80%. (Granted, with the subject of the retrofit starting out as a drafty, four-story old house, there was plenty of scope for improvement.) In other words, a passive house can be anything from a large, new office building to a centuries-old, traditional house. Below are some examples:

Single-family residence in Brooklyn, NYC | Gregory Duncan

Eurogate Sozialbau, Vienna – Europe's largest PassivHaus settlement? | Tiger46 on Flickr

Passive house office building in Austria | Tõnu Mauring

What does a PassivHaus cost?

The Footprint article on the Princedale Road Retrofit for the Future project includes an interesting breakdown of the cost / payback time / bills before and after completion, making a comparison between refurbishing to PassivHaus or Decent Homes criteria. The Green Building Store, in conjunction with Building magazine, has also provided a breakdown of costs for the Denby Dale PassivHaus in West Yorkshire.

What about air quality?

The more passive (or other enclosed, airtight and sealed) houses we construct, the more important it is that we keep monitoring and assessing the quality of the air circulated in these buildings. Are we avoiding moisture build-up? Is the air too dry? Is there enough of it? Will we see a concentration of emissions inside these buildings, over time, from the building materials used? What are the potential positive/negative effects on occupants’ health and well-being? Housebuilder’s Bible author Mark Brinkley experiments with air quality and CO2 levels in this House 2.0 blog post, relating his findings to PassivHaus standards.

To ensure a good level of fresh air supply, most passive houses are ventilated and heated by mechanical ventilation with heat recovery (MVHR). Heat from the warm air that is being extracted is passed to the incoming fresh air through a heat exchanger – with the result that heat loss is minimised and heating costs are reduced. Ducting is an integral part of this: “Marion Baeli, the architect on the [Princedale Road] project, stressed that in a retrofit with MVHR, the coordination of ductwork requires considerable design attention, and should be integrated right from the start.” (Footprint)

Airflex Pro suspended ceiling ductwork installation (Airflow Developments on ESI.info)

Which products are used in a PassivHaus?

The PassivHaus Institut provides a list of certified building components, products and systems suitable for use in PassivHaus construction. Presumably, as this concept gains popularity and awareness, the list will grow. We have already looked at ventilation. Other important components are energy-efficient windows, airtight seals and thermal insulation.

But of course, a component is only as good as its installation. As well as architects who know how to design a successful PassivHaus, and manufacturers who can make products suitable for this type of construction, we need contractors with the right skills and experience. (PassiveHouse Builders, Passivhaus/LCC, Passive Development and Viking House are some of the firms I have come across.)

Project Green Home, Palo Alto | Mark Hogan

What is it like to live in a PassivHaus?

Bill Butcher, the construction manager of the Denby Dale house, kept a 17-instalment diary during the building process. But what happens post-occupancy? How does the building perform, and how does it shape the lives and behaviours of its occupants? In a separate post, I have taken a closer look at the realities of living in a PassiveHouse.

What is the next big thing after PassivHaus?

In the absence of a unified, international environmental standard for buildings, there is a certain amount of ‘competition’ between the different accreditations. There is no shortage of acronyms to choose from, and there are almost as many opinions on which accreditation makes the most sense as there are design-and-build professionals. (For a sensible take on PassivHaus vs the Code for Sustainable Homes, see “The Bout of the Decade” by Sustainable Homes.)

Andrew Holt heads the practice Architectopia in Norway, and also runs a course on sustainable architecture. He has worked extensively on PassivHaus developments. In an Arkitektnytt.no article, he talks about what the next big thing after PassivHaus might be. Mentioning BREEAM, zero-emission housing and “plus houses”, Andrew emphasises the importance of tailoring the standard to the individual project, using different tools to come up with a package that is fit for purpose. He comes to a refreshing conclusion (my translation):

What follows ‘after’ the PassivHaus standard should be a variety of different possibilities, so that our ambitions are based increasingly on the individual project and its local climate and conditions. This would facilitate greater innovation, creativity and cross-disciplinary co-operation. This approach demands a high level of competence within the project team.

An understanding of what the PassivHaus standard is, is a prerequisite for high-quality construction within the energy-efficiency sector. An understanding of what the PassivHaus standard isn’t, is a prerequisite for moving forwards.

PassivHaus office in Langenhart | Train.bird on Flickr