31
The
Case for Eco-retrofitting
a major source of toxic landfill – even with far more reuse or recycling of building components.
Until the 1980s or so, older conventional buildings had many components as well as insulation
materials containing asbestos (it was allowed in some products in Australia until 2003). Asbestos
is still found in many buildings, and its toxic fibres are released in demolition, renovation and fires.
Hence renovation, as well as demolition, of durable buildings usually requires licensed asbestos
removalists. However, eco-retrofitting that ‘encapsulates’ old buildings (especially where asbestos
is involved) could, in some cases, be better than deconstruction and recycling materials that are
harmful during production, occupation, demolition or deconstruction.
Historic buildings have
been preserved by, in essence, adding a new interior. For example, a new concrete floor was poured
into an old city hall building in Portland, Oregon, to level out the warped floors.
This created a
base for new interior walls that encased the old walls. This method contributed to high insulation
levels, as well as the building’s longevity as a landmark, and avoided some of the environmental
and human health costs of demolition and new construction. So reusable, replaceable components
can make sense, but sometimes encasing old buildings in compostable, healthy interior skins
may be better.
Alternatively, eco-retrofitting buildings with demountable and reversible
Green
Scaffolding exterior skins can increase building longevity, reduce the negative impacts of existing
development, and increase design quality and choice – without wasting materials and energy
[Box 5].
Figure 3 Eco-retrofitting example
In this hypothetical case, the building is massive in embodied energy, and impractical to demolish due to its
central business location. However, it is considered an eyesore and has outlived its practical functions. Green
Scaffolding could be applied, using a horizontal triangular truss. This encloses a duct to circulate air from hot
to cold areas of the building in winter and cold to hot sides in summer, aided by solar fans.
In hot weather, the greenhouse terrarium windows vent to the outside. The heat is also expelled from the
Trombe wall, assisted by wind generators.
In cool weather, heat is circulated by the horizontal truss duct.
The heat is fed into and stored in a ‘Trombe wall’ (in this case a rock mesh in the module). We can call this a
‘reverse’ Trombe wall, as it is added to a section of the building that has no windows.
The Trombe wall storage
can feed into the existing centralized system. Alternatively, heat can be directly vented into the room.
Planters are alternated with the terrariums to alleviate the heat sink effect and articulate the façade. They
are electronically shaded, and sprayed with water pipes hidden in the triangular ducting. The planters are
accessible through the terrariums, but sensors will guide a plant maintenance system to reduce the need for
manual gardening. Water for the plants could be collected on the roof. This building is in a humid climate,
so evaporative cooling and roof water collection are limited.
In this case, plastic canopies on the roof would
collect water from the air while providing some additional shading.