Green retrofit and embodied energy
With the spiraling cost of building materials, it makes sense that instead of constructing new buildings, it is usually more economical to retrofit or renovate existing buildings to accommodate new usage.
Similarly, when a new building is constructed, materials recovered from demolished buildings can be reused not only to reduce construction waste, but also to reduce the embodied energy associated with building materials.
Embodied energy is the energy needed to produce building material from the extraction and processing of the natural
resources to manufacturing, transport and product delivery.
Just to illustrate, wood has a low embodied energy compared to steel, which requires a lot of energy to process. Materials normally recovered from demolition of buildings or homes are doors, windows, stones, decorative grill works, etc.
In many cases, it may be obvious that retrofitting is the way to go. But in some unusual cases, the answer may not be clear whether to demolish or build from scratch.
An extraordinary project we handled was a project site for a home with a huge pool occupying most of the property.
It was actually an abandoned koi pond with dimensions and depth like that of a regular swimming pool with cylindrical filter chambers on the side of the pond.
The critical question was: do we demolish the pool or not?
The clients obviously did not need such a big swimming pool. If we decide to demolish the pool, it would have been a huge and expensive undertaking since the pool had thick reinforced concrete walls and floor slab.
After a careful evaluation of the problem, we came up with the solution that met the clients’ requirements.
Since they wanted a two-level home with an accessible ramp for the use of a disabled member of the family, we decided to retain the pool which already provided a natural void space for the rooms at the lower level.
In the end, the existing pool, which seemed to be a disadvantage or an encumbrance in the beginning ended up being a very good asset for the clients.
Having strong thick reinforced concrete walls at the base of the house meant structural stability at no extra cost.
For many retrofit projects, while it may not always be possible to reuse existing structures, it makes good sense to review the advantages of retaining existing structures before doing any massive demolition of a potentially precious resource.
According to Prashant Kapoor, Principal Industry Specialist-Green Buildings at the World Bank Group (IFC),
embodied energy is about the way a building is built rather than how it is used. It concerns the upstream value of the energy consumed by all of the processes associated with building production, from mining and the processing of natural resources straight through to manufacturing and transport.
Embodied energy is the “front-end” component of the lifecycle impact of a building— and it is the part that can never be changed.”
Embodied energy is part of a set of best-practice options being introduced by EDGE, which stands for “Excellence in Design for Greater Efficiencies.” It is an innovation of IFC, a member of the World Bank Group.
EDGE focuses on resource efficiency namely, energy, water and embodied energy of materials. It is a building design tool, a certification system, and a global green standard for nearly 100 emerging market countries.
The program is for anyone interested in the design of green buildings, whether an architect, engineer, developer or building owner.
The free software is applicable for homes, hotels, offices, hospitals and retail with building-specific user guides accompanying them.
EDGE offers a set of technical measures that when selected will reduce a building’s operational and embodied energy and water use. To achieve the EDGE standard and qualify for certification, a building must achieve a 20 percent reduction in energy, water and materials.
The Philippine Green Building Initiative or PGBI is the sole certifying body for EDGE projects in the Philippines.
The author is the Principal Architect of A.P de Jesus & Associates-Green Architecture, and President of the Philippine Green Building Initiative, a green building rating system.
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