course material

1. BLDG1016 Building Science
Answers:
Introduction
There has been an increasing call to curb the negative effects that may result from climate
change. Climate change has become a thorny issue in the recent past as the world gets more
industrialized. Industrialization, though it has brought a fair share of advantages, one of its
main undoing is its unfriendliness to the environment. This has prompted action plans and
even the formulation of United Nations Sustainable Development Goals (UNSDGs) on
environment. This say, there is a global call towards achieving net zero emissions by the
year 2030. In the building sector, this has meant that structures constructed be geared
towards efficiency and more so energy efficiency. Since structures play quite a vital role in
the energy consumed in a state, professionals in the construction sector such as engineers
and architects are stepping up in their roles to minimize the effect of buildings in
contributing to emissions and pollution of the environment. The starting point of the action
of the sector professionals is common since it involves the wholesome process of
construction, from the planning, to design and implementation (construction) phase. Quite a
huge significant of emissions from building structures is based on the type of materials used
in the construction of the building. In fact, more than any other building component or
process, careful selection of construction materials can have very significant impact on the
embodied energy from buildings. To ensure sustainability of the buildings while conserving
the environment, it is thus necessary that prior to construction, the materials to be used
should be evaluated. Those materials that may result in negative environmental impacts
should be discouraged for use while those with relatively lower effects should be
recommended for use, where practicable.
Embodied energy could be taken as the sum total of the energy that is realized from the
overall construction process such as the manufacture, transportation, use and even
demolition of building materials. This presents a whole life cycle perspective to the energy
that can be emitted as a result of construction materials. To make buildings more energy
efficient, the choice of construction materials is thus important. This paper seeks to
establish the relationship between the choice of building materials and the embodied
energy in a building project.

2. APDesign CAD package is to be used to help in the theoretical analysis of this relationship
between embodied energy and the choice of construction materials in a building project,
real or imagined. APDesign is advantageous as it is practical and fast and can estimate
embodied energy figures, mass value and CO2 emissions from CAD drawings. The software
is also quite simple and straightforward in its usage, making it within the reach of many
people.
Findings: A Theoretical Case Study
These findings are based on a theoretical case study of a typical residential dwelling. The
figure below gives the typical residential CAD drawing to be used for the purposes of this
report.
Figure 1: 3D CAD drawing of a typical dwelling
The dwelling above is a simple family home constructed using brick veneer, on a concreted
slab with its internal stud walls aligned with the plasterboard. The roof is taken to be timber
framed with concrete tiles. The doors and windows are timber framed. The kitchen and
washroom fittings are of standard quality. The calculations for the embodied energy of this
dwelling are to include the paintings and carpeting. The furnishings and the blinds have not
been considered for embodied energy calculations. Graphical and tabled analysis will give
the relativities between the different materials and items used in the construction of the
house in terms of their mass values, carbon (iv) oxide and embodied energies. The analysis
will also enable a comparative analysis on the different construction materials and
techniques.
For the analysis, the materials used for the construction of the dwelling were divided into
elemental groups such as the substructure, columns, beams, upper floors, staircase, roof,
external walls, widows, external doors, internal walls, internal screens, internal doors, wall
finishes, ceiling finishes, floor finishes, fitments, sanitary fixtures, special equipment,
sanitary plumbing, water supply, gas service, space heating, ventilation, air conditioning,
fire protection, electric power and lighting, communication and transportation systems
among others.
Expectedly, most of the embodied energy of the simple dwelling were in the substructure,
and the external walls according to figure 2 below. The roof, windows, staircase, electric
power, lighting, plumbing and the floor finishes also have a significant contribution.
Figure 2: Graph of embodied energy by element category

3. Classification in terms of material groups resulted in the following material groups;
structural steel, stainless steel, aluminum, copper, zinc, timber, plastic, concrete, rubber,
masonry, paper, glass, plaster, fabric, stones, ceramics and chemicals. Concrete produces the
highest CO2 among the material groups followed by masonry, plastic, steel and ceramics in
no particular order. This is captured in the figure 3 below.
Figure 3:Graph of CO2 emissions by material category
Individually, brickwork and cement contribute to the highest amounts of carbon (iv) oxide
emissions as document in figure 4.
Figure 4: Graph of CO2 emissions by some common materials
Theoretically then, it can be inferred that materials which had the lowest embodied
energies are the same that produce the most CO2 emissions in the dwelling. Conclusively,
the total embodied energy that is consumed or the carbon (iv) oxide that is generated by the
case study dwelling, or a part of it thereof, should be the target carbon (iv) oxide and not the
specific materials.
Discussion (Analysis)
Until recently, there has been little and unhelpful information on a one off calculation
process for embodied energy and Carbon Emissions on the different types of construction
materials. This in a way, has over the years hampered the formulating of techniques to deal
with the adverse effects of unsustainable buildings. Until recently, more developments and
software based ones such as APDesign have eased the process. Use of the software is faster
and produces a much more reliable output. In order to quantify the energy embodied in a
building, estimation of the quantities of the materials used is to be done in a disintegrated
process to the extent that the components can be separated by the major materials. From
the database, the energies related with each of the construction material can then be
multiplied by the material quantities. Aggregation of the products from this step then
results in the totals for each element. As seen in the findings above, the embodied energies
in the construction materials are obtained through input-output graphs/tables. The use of
the software eliminates the need to define or verify values and set system boundaries. This
makes the whole process much easier.
The APDesign model will always give the designer a measure of the whole environmental
impact of a structure or a part of the building thereof, through a unique perspective. Most
construction sector professionals such as quantity surveyors and designers are usually
aware of the elemental cost planning approach to the disintegration of a building to its

4. elements . While it is an accepted approach, it can only compare the costing of building
elements and the embodied energy effects. It does not go further to look into the individual
materials. Through the APDesign, embodied energy values of any construction material
could be known anywhere, at any stage of the construction process thereby allowing for
remedial measures to be taken in case of challenges. Trade-offs are also common when
using the software. For instance, a particular building material may have very high figures
in embodied energy at the time of manufacture but will require very minimal energy for
installation and subsequent maintenance. Adoption of the material after comparison with
the alternatives provides the best fit solution. Since the effects of embodied energy is best
evaluated at the early stages when the buildings are still in the design process, the focus is
easily tailored to the contributing materials. This gives a more detail analysis and a bottom
up approach instead of a top down approach that will entail disintegrating an existing
building into its elemental self. The investigations on material usage can also be done at the
early stages before finalized designs are produced.
From the output in the findings, it is quite clear that the design software is a success, that
could be developed even further. The ability of the software to estimate carbon emissions
and embodied energy levels straight from design CAD drawings is a huge positive. In fact, it
is not just about the study, but also that a detailed and thorough study could be conducted
through the software. The method is not only accurate and effective but it is also fairly
simple. More and more sophisticated programs are being formulated to make even work
easier in the estimation of embodied carbon, CO2 emissions and mass values.
Conclusion
Construction materials and how they relate to the embodied energies and carbon emissions
in buildings continues to be an important domain in the construction industry. The ability to
have accurate assessments to the most basic of the building (materials during construction)
is thus important. These days, computer aided design softwares such as the APDesign
provides a platform for easier and faster assessment of individual construction materials
from mere CAD drawings. Taking a design analysis and quickly and effectively comparing it
with other alternatives is now a task on the go. The embodied energy generated by a
development or a part of the dwelling should be the focus of reducing emissions and not the
specific materials themselves. Softwares and other evaluation frameworks can give easier
analysis for informed decision making on the balance needed for the choice of construction
materials and embedded energy.
Implementation
More and more construction sector workers should be urged and actually trained on the use
of various frameworks meant to make work easier when evaluating the choice of
construction materials. This way, the sector will be strategically aligned to have faster and
best alternative choices for construction materials and more sustainable buildings. Even

5. more, innovation should be encouraged to have better frameworks and systems with more
detailed analyses and better output.
The use of other methods of evaluating buildings and their components wholesomely
especially in terms of costs of materials may be limiting. Having a proper breakdown from
the whole structural envelope to the elements and the constituent of the elements and to
the individual materials is in itself a tiresome and time consuming process. Having the take
offs done from CAD drawings is a plus, safe, efficient, accurate and much faster and is
hereby encouraged.
Recommendations
Based on the findings and subsequent discussions related to the choice of building materials
and embodied energy of construction materials, the following recommendations are fit for
this report;
The analysis of embodied energy and carbon emissions of buildings are better done at the
earlier stages of the project to allow for the chance to consider alternatives or even have
different designs altogether.
There is a huge opportunity to integrate the traditional and conventional life cycle
assessment of building methods with faster, cheaper and accurate methods to achieve high
reliable results for the sustainability of buildings.
The already developed frameworks and software for the analysis of the best construction
materials could be advanced more through additional sophistication to their abilities.
Features such as extensions could be made and the process of developing these
frameworks, software could be a continuous process.
More focus could be placed on the predominant construction materials such as concrete and
steel and the various methods by which their embodied energy and by extension, carbon
emission could be formulated.
There is a need to carry out campaign among members of the public with view of drawing
them out of the much experienced consumerism behavior. This will allow the construction
sector stakeholders and other enthusiasts and even the public to stop viewing residential
developments or any other types of houses from a functional perspective only. The
promotion of other fonts of consideration such as environmental concerns is highly
recommended.
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