Construction completed: December 2011
Architects: Steffen Welsch Architects in collaboration with Damien Thackray (terminus studio)
Builder: Camson Homes
Joiner: Woodcraft Mobiliar
House size and land size (in sqm):
House: 60 sqm (double height with additional 17sqm mezzanine) with 62 sqm deck, Land: 5588sqm
Building star rating: 7.5 stars
The addition of an additional ply skin to all timber framed walls during construction – for structural and additional fire-proofing reasons with obvious thermal benefits – increases the overall R value of that wall system from R3.7 to around R4 and realistically lifts the overall rating to 8 stars
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Hot water:
Quantum 270L heat pump
Chosen as it is not dependent on solar access, which is severely limited for 6-8 months of the year in Marysville.
Renewable energy:
As above – not enough available sunshine through so much of the year to make solar pv viable., especially as the project is a compact weekender rather than a permanent dwelling. The focus was on really minimizing the energy consumption footprint – including embodied energy – through the other range of strategies, including specificying LED lights throughout.
Water saving:
Bluescope Slimline Colorbond 5000L rainwater tank. Cistern and laundry plumbed into rainwater tank.
Passive design / heating & cooling:
- House is sited for optimum northern solar access on a difficult sloping site with a nth/nth west orientation and Mountain Ash forest on the ridge above screening morning winter sun. House is located on the southern end of the exisitng terrace to allow for as much clear unimpeded access to sunlight as is possible in these conditions. High windows on east elevation located to capture all available winter morning rising sun and then trajectory of morning sun as it swings around.
- Full height glazed corner on the north elevation, with 3 smaller windows and the sole west elevation window then continues to capture all the available winter sunlight across the day as the sun swings across that aspect of the site.
- In winter the space, whilst cool in the mornings with the fire having died off overnight, heats very quickly once the wood heater is lit in combination with the morning sun penetrating the east elevation punctured openings.
- In summer the north and west openings are designed in combination with double height façade to minimise penetration of direct sunlight into the interior space. Materials used across the north façade and deck prevent any additional reflection and glare from bouncing into the space.
- West elevation half timber half block wall minimises heat load impact of western sun through summer.
- Heavily insulated lightweight wallsTimber framed walls – 140mm laminated timber frames with 120mm bulk Glasswool insulation Bradford Wallwrap sisilation (fire rated) and ply skin. Timber cladding on battens to create air cavity to assist with air movement R4.0
- Double block insulated cavity walls with Foilboard Super 15mm in 50mm cavity – R2.5 – to south and west walls. Block walls provide considerable thermal mass benefitfor interior given compact size of the dwelling and provide coolth to outdoor area adjacent the kitchen/ bathroom during hotter pats of the day, which is shaded by double height wall.
- Sub-floor insulation – 15mm extruded polystyrene rigid insulation R1.5
- Roof – Anticon 55 Bradford 60mm blanket with reflective foil on underside and 185mm bulk Glasswool ceiling batts R6
- Operable windows located to catch prevailing breezes during summer
- High operable windows to facilitate thermal stack effect through double height volume during winter and summer
- Windows positioned generally to optimize cross ventilation
- Deck posts to fix sunshade to in summer to live outside and to remove in winter to allow full penetration of winter sun
Active heating & cooling:
- Norso 7648 woodheater from Wignells of Melbourne. Selected for its beautiful compact appearance in a small space, its efficiency – 73% – and relatively low emissions – 3.4Grms – and 99% scrap iron content.
- Universal reverse cycle ceiling fan
Building materials:
- Timber-framed walls clad with a radially sawn silvertop ash skin – Radialtimbers
BAL 29 rating bushfire resistant species. 140mm laminated timber frame, 6mm ply skin, 35mm battens, silvertop ash boards. - Solid core 90mm Boral Ash Grey double block insulated cavity walls to the south and west
- Fully enclosed double block floor as above
- Galvanised steel entry canopy and bathroom window reveal
- Blackbutt wharfdeck decking boards by Urban Salvage
- Red ironbark to deck sunshade posts and external stair posts and handrails
- All external timbers were required to comply with the requirements of the BAL 29 rating, which has additional benefits in terms of considerably enhancing the expected durability and life cycle of the timber given its increased density. For example the deck frame timbers are F27, a grade which is rarely used. The selection of feature timbers was driven by the likely weathering properties in what is a very wet and cold climate, with the emphasis on durability and character, and its fire resistant properties.
- Lysaght Kliplok 700 Colorbond Nightsky metal deck roof and roof plumbing
- FC sheet cladding to laundry/ store
- Big River Blackbutt armourpanel flooring –
- Hoop pine ceiling lining and cabinetry
- Recycled redgum mezzanine ladder and benchtops
Windows & glazing:
- All doors and windows are timber framed double glazed (glazing on west and east elevations minimized) with the exception of the bathroom window which is aluminium double glazed. Outer pane glazed doors 6mm toughened and windows 5mm toughened pane due to BAL 29 rating requirements. Additionally the timber is a denser hardwood than would typically be used because of bushfire BAL rating requirements.
Lighting:
- LED downlights aand exterior spot and stair lights from Artemide and Laser Lighting
2 Compact fluorescent pendants
Paints, finishes & floor coverings:
- Haymes low VOC to internal walls and inside face of window frames
Cutek CD 50 with UV protection tint to timber cladding, door and window frames and deck
The project, a weekender for a Melbourne based family of 3, encompasses re-building and re-inhabitation post the 2009 Black Saturday mega fires, which decimated Marysville.
It is a 60 sqm double height (with sleeping mezzanine) ‘container’ with 62 sqm deck on 5588sqm of land. The site, a steeply sloping site, backs onto the nearby state forest and overlooks the town. The building is sited on the existing terrace where the previous house stood though re-oriented.
The project negotiates the issues of building in response to fire risk, notions of the bush shack and urban sensibilities of dwelling, sustainabilty and comfort, and crafting a series of overlapping inside and outside spaces that bring the occupants into frequent, surprising and delightful encounters with the unique phenomena and texture of its bush setting. Notions of resilience, impermanence (and most interestingly the points of resistance and tensions therein) , adaptability, reciprocity, economy and beauty were central to the design process.
Container
The original brief asked for a larger much more conventional replacement ‘house’. Across a period of 12 months immediately post the bushfires the perceived need to replace like with like gave way to the notion of something more emblematic of the bush retreat – a resilient, stripped back and compact container: a timber box in the forest resonant of the original settler shacks in dialogue (not always reconciled) with urban tree change sensibilities and the refinements that that insists on; a space that ‘houses’ more simply and fluidly the range of family and friends place-centric activities that the typical weekender in the bush traditionally has aspired to; a building that confronts directly the reality of building in a bush fire prone landscape without surrendering to exclsuively defensive responses, and which accomodates ideas of impermanance.
A double height volume comprised of a main living area with kitchen and bathroom beneath a sleeping mezzanine at the rear. A separate laundry and storage ‘box’ is integrated into the southern boardwalk external to the house. The volume of the house sits on a fully enclosed double block sub-floor base and is locked into a series of decks, which connect the north of the site to the south, the upper terrace where you arrive by vehicle to the lower terrace on which the house is situated, and extend the available living space.
The 3m deep mezzanine allows the space for kids to play ‘upstairs’ to free up the main room but remain in visual connection through the balustrade screen with the adults below. The double height west wall, which has one high level opening, is used to project movies.
The graft
A timber skinned lightweight frame is grafted onto a masonry base and double height masonry walls to the south and part of the west. The block wall and base is also the anchor, which permits the timber box to slip and shift to orient itself according to fire risk, forest, natural light, sky, town. The idea of the graft refers to the grafting of the new onto the original, the urban onto the shack, a resilient though inevitably fragile container onto the sense of mass and permanance offered by the block anchor.
Light
The east elevation features a series of 500mm x 500mm punctures across the dobule height timber skin of that façade. Diurnal and seasonal light animates both the surface of the façade and the interior. The morning sun rising beyond the ridge above casts a shadow cast projection of the forest across the skin of the façade. The double height expanse allows for the floor and interior west wall to act as a projector, capturing the cyclic play of natural light. Both serve to collapse the psychological distance of the forest, to bring the occupants into everday cyclic contact with the phenomena of the bush setting, whilst maintaining a sense of secure physical distance.
Views
Openings are located according to fire risk, natural light, passive solar and passive cooling strategies and ideas of the oblique or glimpsed and collaged view as well as dramatising the verticality of the mountain ash setting and the horizontality of the distant ranges.
Fire risk and memory
The project was an opportunity to address in its own modest way the problematic of re-imagining the idea of house on behalf of the issue of dwelling in the Australian interior landscape – specifically a bushfire prone one. How do we dwell, resiliently, durably and meaningfully with the Bush – as it is rather than as it is typically sentimentally or fearfully rendered.
The design process was one of grappling with the tensions set up by the intersection of the ambition for the project and the set of complex constraints. – how to, for example, respond appropriately to the new more rigourous BAL regime and account for the likelihood of possible future bushfire events without being excesivley definined by that rationale and so resorting to purely defensive strategies with the inevitable bunker-like outcomes that that would engender.
Retaining memory, so as to insure against forgetfulness and future unpreparedness was an important consideration. For example, the chimney and cavity which housed the wood heater, previously the social and physical hinge and anchor of the house, was the only element still standing and familiar. That became a key moment on behalf of the future design and a device for connecting the new to the past. The rear block walls and basse refer, in part, to that remnant of the original house.
Collaboration
This project was a collaborative one between myself and Steffen Welsch Architects as the design team. The builder, Camson Homes, also came onboard early in the process so as to ensure, given the complexity and unknowns of the process of re-building in a bushfire ravaged area, as much construction expertise and commitment to the project as possible.
The Camson team did a superb job of guiding the project through construction, building with an especially high standard of craft and commitment to the intent of the design and the desire to start over. The building is what it is because of the craft with which the builder realised the vision for the project.
Siting and design principles and strategies
ESD, fire risk, views, living between inside and outside and connection with the phenomena of the site including the climate and the forest
The house is sited to:
- maximise northern orientation
- minimize fire risk
- respond to the steep topography of the site with the associated problems of access to sunlight, fire risk and livability that poses
- enhance physical and spatial connection with the site encompassing the immediate terrace and extending out into the garden and the forest beyond
- capture the various outlooks including the town of Marysville to the west below and the hills and mountains of the Yarra Ranges to the south
- reinforce the opportunities to live fluidly between inside and outside (given the compact amount of actual living space).
The house is sited on the southern end of the existing terrace, where the previous house was located. The siting has been determined by a series of interdependant considerations. It is the optimum location for maximizing northern solar access, which is very limited because of the orientation of the site, the fact of the Mountain Ash above the site on the crest of the ridge which blocks much of the winter sun, and the endless clouded over winter days.
It is the location which most minimizes the potential from any future fire hazard from the range of fire risk scenarios which had to be negotiated. It allows the best connection between the two terraces cut into the slope of the site and the house so as to live across those overlapping spaces as much as possible. And it is located to take best advantage of the series of views and outlooks.
Materiality
The framed walls of the building have a radially sawn silvertop ash skin. The timber was selected for its fire resistant properties – the BAL 29 rating limited the range to six bushfire resistant species – its durability in the climatic conditions typical of this low mountain terrain, its tonal characteristics as it weathers and because of the radial sawn log yield by comparison with normal methods. The timber has been blackened off to reflect the charred trunks which still dominate the landscape – another means of embedding memory within the project.
Currently the house as a whole recedes into the landscape as a consequence, especially when viewed from the town. The play of sunlight across the surface of the timber at different times of day and year however gives effect to a variable and transitory tonal range across the east and north elevations in particular. Over time as it weathers and the surrounding garden and forest rejuvenate further the intent is that the timber will achieve a more subtle contrast with its surrounds.
Energy rating
The project has a pre-construction BERS V4.1 energy rating of 7.5 stars. The addition of an additional ply skin to all timber framed walls during construction – for structural and additional fire-proofing reasons with obvious thermal benfits – increases the overall R value of that wall, which means that the project is more likely around the 8 star mark. The performance across the first winter reveals that it is very comfortable with the wood heater only needing to be on a slow burn.