sanctuary magazine issue 14 - dutch courage - amsterdam green home profile

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hoUSe pRofile AmSTeRdAm

AN AmSTeRdAm ARChiTeCT TAkeS The TRAdiTioNAl CANAl hoUSe eNeRgY-NeUTRAl

courage Words AnnA Cumming PhotograPhy John Lewis mArshALL & hAns Peter FöLLmi

Gthe home’s mezzanine living room is suspended on an entire elm trunk cut down and salvaged from beside one of Amsterdam’s canals during a quay reconstruction project. Photo by John Lewis marshall

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on a series of artificial islands in a sea lake east of central Amsterdam, a new residential area called IJburg is taking shape. The blank canvas is giving designers the opportunity to reinvent the traditional narrow canal house that characterises the old city centre. Although IJburg is not specifically a “green” development, for his house on Steigereiland (Docks Island) Pieter Weijnen of FARO Architects set himself the ambitious target of complete energy neutrality: zero net energy consumption and zero annual carbon emissions. He was well positioned for the challenge. Inspired to take action after seeing the Al Gore climate change film An Inconvenient Truth, Pieter designed and built his first energy-efficient house, the Steigereiland 1.0 residence, nearby. During this project, Pieter was already realising that he could go further. He incorporated a range of new features into the design for Steigereiland 2.0 and chose materials that fit into a “cradle to cradle” lifecycle, all with an eye to reducing the house’s lifetime CO2 emissions to as close to zero as possible. Pieter’s strategy was three-pronged: firstly, he used careful design and comprehensive insulation to ensure strong passive thermal performance. This makes it possible for the house’s minimal active energy needs to be met using small-scale renewable energy technology – the second prong. Thirdly, the “cradle to cradle” principle: “materials used in the house can be re-used or recycled without additional CO2 output,” explains Pieter. “For instance, the matting just under the floorboards is made of old mattresses. This matting is not glued onto the structure, but lies loose so that when the house comes to be demolished those mats can easily be pulled out and used again.” Materials were chosen for longevity and low maintenance. The house’s structure is timber, with adobe bolstered with phase changing material in some walls to provide thermal mass. To avoid the need for paint or other sealants on the exterior, the facade is clad with larch that has been scorched. This traditional Japanese technique blackens the surface of the wood, preserving it and giving the house a natural, textured look. The result of all this attention to detail is a light, very liveable home that performs well thermally, even during the cold, dark Dutch winter. The four-storey townhouse squeezes a generous 230 square metres of floor space and three bedrooms into its 72 square metre footprint. On the ground floor, the front door opens into an entryway that acts as an airlock, insulating the main living space from the outdoors. Through

the internal door, the open-plan kitchen and dining area is lit by large windows in both facades. The floor is granite-tiled, acting as thermal mass to absorb warmth from the sun during the day and release it slowly at night. Suspended above the kitchen on a beam fashioned from a whole tree trunk is a mezzanine living room. Above, the upper floors house three bedrooms, two bathrooms and a plant room. In his quest for energy neutrality, Pieter paid close attention to the thermal efficiency of the house. He claims that the joints are not only liquid-tight but air-tight, and believes that his family has the world’s best-insulated cat door! The entire building envelope is insulated to R10, helped by organic wood fibre insulation in the walls and cellulose in the roof. A flexible Aerogel blanket insulates the very tight spaces. All windows are triple-glazed and the wooden window frames include thermal breaks to prevent the conduction and loss of heat to the outside. In fact, careful thought was given to the elimination of thermal bridges in every aspect of the construction. Heat is not lost even when ventilating the house. A heat transfer unit harvests warmth from the “used” air and transfers it to the fresh air brought in from outside before it is circulated inside. Extra help to further warm outside air in winter or cool it in summer comes from a ground source heat exchanger sunk two metres beneath the house, where the temperature is relatively constant. [For more on ground source heat pumps, see p72.] On the roof, an urban wind turbine contributes to the house’s energy needs, and integrated photovoltaic cells will be installed soon. An evacuated tube solar heat collector built into the rooftop parapet provides hot water for floor heating and for kitchen and bathroom use. Pieter is particularly pleased with the power, heating and ventilation systems incorporated in the house. “These were all state of the art and untested when we put them in, and now we can use the results from this house to innovate for other and larger projects,” he says. The experience of building his second energy-efficient house has strengthened Pieter’s feeling “that we as architects should do much more to create a more sustainable environment.” The Steigereiland 2.0 residence is certainly helping. With the small physical footprint of the traditional Amsterdam canal house, its carbon footprint is even tinier – truly a house for a new era of sustainability.

Further information about the IJburg development: www.ijburg.nl/english

Materials used in the house can be re-used or recycled without additional CO2 output

GLarge windows on the sunny south-east facade let warmth in during winter and are fitted with shade screens for summer. the narrow windows are recessed to provide shading from the sun, and the facade is clad with scorched larch. Photo by John Lewis marshall

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Dthe family’s favourite thing about the house is that it’s light and open, and yet private. the mezzanine living room in particular “feels like a warm nest and brings cosiness to the vast volume of the house”. Photo by John Lewis marshall

GCustom-designed LeD lights at floor level cast patterns on an upstairs floor, and help to light this internal walkway. the custom-made pipes embedded in the adobe wall are part of the heat recovery ventilation system that operates throughout the home. Photo by John Lewis marshall

mosa granite tiles were used for the house’s slab floor. wide double doors open to the south-east facing garden. Photo by John Lewis marshall

Dthe elm trunk was lifted into place early in the construction process, and the house then took shape around it. Photo by John Lewis marshall

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sustainable featuresRenewable energy

Roof-mounted DonQi 1.75kW wind turbine

Hot water

– Evacuated tube solar heat collector system built into

the rooftop parapet provides hot water for floor

heating and for kitchen and bathroom use

– 2000L of boilers provide a large energy store

for slab heating

Water saving

Rainwater is collected in an in-ground tank under

the back garden and used for toilets and laundry

Passive heating and cooling

– Clay plaster used on kitchen and upstairs walls

for thermal mass

– Phase changing material in the form of BASF

Micronal PCM paraffin balls used in the walls on

the top level www.micronal.de

– Large windows have adjustable shade screens

Active heating and cooling

– A heat recovery ventilation system recycles heat by

transferring it from “used” air to fresh air without

mixing them; the air can be further heated in winter

and cooled in summer using a ground source heat

exchanger located two metres beneath the house.

See diagram on p28.

– In-slab floor heating using solar-heated water

– Pellet stove provides booster heat to the warm water

heating system when needed

– Wood stove in the mezzanine living room for space

heating when needed

Windows & glazing

– Triple glazing to all windows

– Insulated window frames with thermal breaks

Insulation

– Organic wood fibre and cellulose insulating

materials in the walls and roof

– Insulation under floor slab

– Entire building envelope insulated to R10

– Completely air- and liquid-tight joints

Building materials

– Structural timber panel walls with reclaimed

timber supports

– Scorched larch timber cladding

– Adobe used for some walls

– Spruce veneer and ply products used on the interior

for some flooring, stairs and balustrades

Paints, finishes & floor coverings

Natural wax finish on interior timber elements,

including walls

sustainable ProductsPhase change materials

A phase change material (PCM) is a substance able to

store and release large amounts of energy by melting

and solidifying at a certain temperature. Recently,

building construction materials containing PCMs that

change phase within the temperature range of human

comfort have been developed, although they are not yet

readily available in Australia. The Steigereiland 2.0

house incorporated BASF’s Micronal PCM phase

changing beads in its adobe walls: microscopic polymer

spheres contain a paraffin wax storage medium, which

absorbs heat above a certain threshold and melts.

When the temperature drops, the wax solidifies and the

stored heat is released. Using products like this can

increase the effective thermal capacity of the material

that contains the capsules and dampen temperature

fluctuations, acting like thermal mass. The Your Home

Technical Manual states that “the technology offers the

prospect of lightweight buildings that can behave with

characteristics associated with ‘traditional’ thermal

mass”. At this stage building materials containing

PCMs are expensive. www.micronal.de

Insulcon Spaceloft flexible Aerogel insulating

blanket in very tight spaces

Aerogels are substances that are made by removing the

liquid from a gelled substance without the structure of

the substance collapsing while it dries. They are the

lightest known porous solids and the best available

insulators and are over 96% air. Aerogel home

insulation is made by binding small aerogel beads

together with a fibrous matt such as polyester fibre.

The end result is a flexible insulator only a few

millimetres thick that has extremely high insulation

properties for its thickness – more than twice the

insulating ability per centimetre than styrofoam and

three times more than fibreglass batts.

www.insulcon.com; www.aerogel.com.au

designerPieter Weijnen/FARO Architects—Websitewww.faro.nl—Project tyPeNew build—Project location IJburg, Amsterdam, Netherlands—cost1550,000(approximately AUD$750,000)—sizeHouse footprint 72 sqm; total floor area 230 sqm; land 108 sqm

AmSTeRdAm ReSideNCe

gRoUNd flooR plAN1 entrance airlock2 Kitchen & dining3 storage

SeCoNd flooR plAN4 mezzanine living room5 study area

ThiRd flooR plAN6 Bathroom7 Bedroom8 Plant room9 Bedroom

foURTh flooR plAN10 storage11 Bathroom12 Bedroom

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All windows are triple-glazed for maximum thermal efficiency and the frames are designed with thermal breaks to avoid heat loss. Photo by John Lewis marshall

the wind turbine on the roof provides power for the house. eventually, it will be connected to the city’s grid. Photo by hans Peter Föllmi

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Dthe fourth floor bedroom. Photo by John Lewis marshall

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Scorched timber cladding

For the facade of the Steigereiland 2.0 house,

architect Pieter Weijnen experimented with a

traditional Japanese technique known as

shou-sugi-ban, literally “burnt cedar boards”.

The technique involves blackening the surface

of the wood with flame (nowadays often by use

of a blowtorch), extinguishing the fire, and then

scrubbing to embed the ash into the grain of the

wood. The charring preserves the timber

underneath and eliminates the need for paint

or other sealants, and renders the cladding

resistant to rot and fire. Larch was chosen

for Steigereiland 2.0, and the boards were

blackened by lashing them together to form

“chimneys” inside which a small newsprint

fire was lit.

[Ed note: we have not been able to find a great

deal of information on the use of this technique

in Australia, so if you’re considering it – and you

might find it particularly interesting if you’re

building in a bushfire prone area – please talk to

your architect/designer and see the following

resources:

– www.pursuingwabi.com/2007/11/05/

shou-sugi-ban/

– www.materiadesigns.wordpress.

com/2009/12/27/

shou-sugi-ban-terunobu-fujimori-

charred-cedar-siding/

– www.dezeen.com/2009/03/11/

yakisugi-house-by-terunobu-fujimori]

AmSTeRdAm ReSideNCe

hoW the heat recovery ventilation system Works in Winter

Fresh air is drawn in from the roof and heated by the ground source heat exchanger, as shown by the solid blue and orange lines in the diagram. Simultaneously, the central heat transfer unit harvests heat from “used” internal air before expelling the air from the home (as shown by the dashed blue line) and transferring the heat to the incoming fresh air. The warmed fresh air is then circulated through the home, after which it returns to the central heat transfer unit where any remaining heat is recouped before the “used” air is expelled outside.

steps involved in preparing shou-sugi-ban: lashing the larch together to create “chimneys”; burning the timber; extinguishing the flame; and the final product in situ in the steigereiland 2.0 house. Photos by hans Peter Föllmi

image courtesy FAro Architects

central heat transfer unit

ground source heat exchanger

150m tylene tube heat exchanger in ground

sanctuary magazine issue 14 - dutch courage - amsterdam green home profile

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