Lightweight Roofing Systems: Advantages, Disadvantages, and Costs

This report, prepared for the Construction in Practice 1 course, examines lightweight roofing systems to reduce energy heat transfer in residential buildings. The report explores three distinct roofing technologies: wood, metal, and felt, detailing their installation costs, advantages, disadvantages, and environmental impacts. The analysis includes a comparison of each material's properties, such as durability, thermal characteristics, and ease of installation, providing a practical assessment of their suitability for larger-scale residential construction. The report also touches on the potential of phase change materials (PCMs) to enhance thermal storage within these systems. The study concludes by highlighting the benefits of lightweight roofing in achieving energy efficiency and environmental sustainability within the building sector. The report includes references and is formatted as per Harvard referencing guidelines.

CONSTRUCTION MANAGEMENT
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Contents
INTRODUCTION...........................................................................................................................................2
Wood Lightweight Roofing Technology...................................................................................................3
Installation Cost...................................................................................................................................3
Advantages..........................................................................................................................................3
Disadvantages......................................................................................................................................4
Environmental Impact.........................................................................................................................4
Metal roof tiles Lightweight Roofing Technology....................................................................................5
Installation Costs.................................................................................................................................5
Advantages..........................................................................................................................................6
Disadvantages......................................................................................................................................6
Environmental impacts........................................................................................................................6
Felt Lightweight Roofing Technology.......................................................................................................7
Installation Costs.................................................................................................................................8
Advantages..........................................................................................................................................8
Disadvantages......................................................................................................................................8
CONCLUSION...............................................................................................................................................9
REFERENCES..............................................................................................................................................10
INTRODUCTION
Most of the governments in the world including that Australia state are already encouraging high
standards and speed of the construction using techniques known as the offsite site construction.
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Also, engineers have been pushing for the construction of structures which meet the
requirements on energy efficiency as well as carbon to effectively observe the stringent
performance of energy. Some of these factors have led to the shift-way from the conventional
materials which have been used in the construction of roofs like bricks and blocks. Instead, a
lightweight timber and steel frame are being embraced (Naji et al. 2014). The shift is because
lightweight materials have complied with the thermal demand of performance.
Any move to the lightweight construction has raised concerns over the comfort of the internal
conditions. This is because of most of the materials used in this type of the construction lack
properties of thermal storage. This leads to the rapid swing of the temperatures internally. The
concern is even more exacerbated by the global warming prediction which has been used to
protect climate change. Recent studies have indicated the likelihood of having drier and hotter
summers. In case there are no optimizations of the newly designed buildings, the advantages
which come from the lowered heating consumption will be lost in the unit of air conditioning
fitted or meant to regulate the properties of the room air (Suzanne 2014).
The existing tension is whether to add more mass to enhance thermal storage by the roofing
materials or to have the construction of more efficient structures that have minimal
environmental impacts. It is for this reason that some of the technologies used involve
applications of phase change materials commonly known as PCMs. These materials are capable
of storing a large amount of heat energy for every unit mass as opposed to the conventional
materials for building. The PCMs store this thermal energy as latent and not just sensible heat
(Wu et al.2017).
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Lightweight roofing can be very useful on several occasions. Some of the situations where it can
be very useful include replacement of the glass roofs for low pitched roofing's, replacing glass
roofs on conservatories as well as for lightweight structures which are used in housings of
timber. Thanks to the latest technology which allow for the wide range of technology for the
options of the low weight roofing that is used alongside other traditional materials. Some of the
most common or popular options of the lightweight materials which one should consider using
include the following:
Wood Lightweight Roofing Technology
This is considered to be one of the oldest materials used in the industry of building and
construction. As a roofing material, wood has been associated with several merits.
Installation Cost
Considering that wood is readily available in various places of Australia and even in the entire
world, the installation cost is never high as compared to other means of the lightweight. On
average it has been estimated that the cost of installation of the wood as a lightweight installation
material goes for $250 for every 850m2. This particular value is even expected to be lower in the
places that have plenty of forests and with lower labor charge for similar services.
Advantages
 The tiles made from wood will always shake or shingles depending on the style which
has been used exactly.
 It is relatively cheap
 It is light hence do not add much weight on the roofing system
 In case it is sourced responsibly, it becomes environmentally friendly.
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Disadvantages
 One of the demerits of using wood as a roofing material is that it wears out very quickly.
This is common in places that experience a lot of moisture. This implies that the structure
will rot very fast. To have the structure kept in proper conditions; regular maintenance
will be needed to ensure that the structure retains its aesthetic value and functionality.
 It has been estimated that roofing from wood can last between 30 to 40 years. However,
this duration is relatively reduced in places like the UK where the temperatures are very
low with the moisture content being high.
Figure 1: Wood Lightweight roofed structure (Suzanne 2014).
Environmental Impact
Wood has very little impact on the environment considering that it can rot i.e. being
biodegradable. This makes it environmentally friendly in all the process of construction. Rotten
wood can be used as fuel and manure.
Metal roof tiles Lightweight Roofing Technology
The research work has discovered that the roof tiles which are stone coated have numerous
advantages just like for the case of the metal cladding. This is common while at the same time
addressing the issues which are closely related to the cladding process. In some cases, there has
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been a consideration on the steel as the base material which is very strong. When the coating is
done with the help of an alloy of aluminum-zinc, then a further coat of the actual stone particles
which are bounded with the use of resin to the surface of the tiles. Such activities will result in
tiles of the roof lightweight which offers the best properties of cladding using metals without
several drawbacks.
Figure 2: Sample of metal roof tiles (Suzanne 2014)
Installation Costs
It is important to remember that that metals and precious stones which are used in the coating
are obtained at relatively higher prices. Also, improvement of the properties of the materials of
metals so that they can be more corrosion resistant implies that they are likely to be more
expensive. On average it has been estimated that the cost of installation is $450 for every 850m2
in most parts of Australia and in the other regions of the world where this type of lightweight
roofing is used (Khowaiter & Saudi 2015).
Advantages
 Considering that metal bases are used in the processes of property improvement, the tiles
are very strong.
 They are very light as compared to the traditionally used materials for cladding
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 Addition of the coating materials made from stone has been known to improve the
thermal characteristics of such kind of building materials. This implies that the level of
noise in the house will be relatively reduced even during the rainy seasons
 The combination of the materials to get alloy product makes the system to be complexly
corrosion resistant.
 The installation process is very easy and it can be fitted by any roofer since there is no
additional or extra training required while handling this particular material. Finally, the
low weight even makes it easier to work within any structure in the building and
construction industry.
Disadvantages
 Alloy products are relatively expensive hence the cost of construction which involves the
use of this particular material is likely to be higher than expected. Its use will, therefore,
be meant for the selected few rich classes.
 Aluminum products are usually known to be attractive shiny metal however with the
incorporation of zinc to get an alloy which is corrosion resistant makes the materials lose
its attractive color (Torkaman, Ashori and Momtazi 2014).
Environmental impacts
As usual, any construction process is associated with the remains of the construction materials as
wastes. Pieces of these roofing materials can potentially pollute the environment and create an
ugly scene. Collection and recycling is thus the remedy for the entire process.
Felt Lightweight Roofing Technology
This is another current technology which is being used in lightweight structures. In the case of
the flat roofs, felt has been considered to be one of the popular options for the roofing. The form
which is commonly used comes in the shape of rolled sheets. They are laid on the top of
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materials which are an underlay. The sheets are made of fibers which are matted or impregnated
with the bitumen (Hernández et al.2014). The processes of impregnation make the components
to be waterproof as well as being durable. The roofing from felt is very light and in case it is
properly installed, it provides an effective weatherproofing.
Figure 3: Use of Felt with and without PCM in the system of Lightweight Roofing (Suzanne
2014).
The studies have shown that latent heat from this particular material may be around 320kJ/m2
(He et al.2016). This is applicable in the cases of plasterboards which are made from gypsum.
The material will thus be expected to display specific characteristics including varying fusion of
heat.
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Figure 4: Felt roofing material used in flat roofs (Suzanne 2014).
Installation Costs
Although it is a common name, the material is not just readily available. This is the reason why
its use is not common as compared to the aluminum products. Due to this scarcity effect, the
installation of the material is relatively expensive. Also, the installation requires training on the
side of the roofer. This makes the entire process very expensive. On average 850m2 will require
$ 300 for installation in most parts of Australia and the common market in the world.
Advantages
They are waterproof as well as durable
They are very light and their proper installation makes them weatherproof
Disadvantages
 It is expected that good roofing which is made from felt can last for over 25 years; the
surfaces tend to tear easily after this period. This implies there will be a need for regular
maintenance which can be expensive as well.
 The installation of this material as a roofing material requires specific skills. If the
installation is incorrectly done the roof will be compromised very quickly.
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 The roofing is only suitable for the flat roofing hence making its application to be limited
to specific areas.
CONCLUSION
Lightweight roofing has been identified as one of the effective ways of ensuring that the building
is cooled as much as possible. The cooling process is achieved by the use of the following
conventional means:
Passive means of cooling: This kind of cooling is achieved through the direct exchange of heat in
the indoor air. This may involve the use of PCM which is incorporated in the materials for
buildings like floorboards, plasterboards, and furniture (Georgeau and Mulder, Chem 2014).
Assisted passive cooling: Passive cooling which has active components like a fan can assist in
the accelerated exchange of heat through the increase of air movement across the PCMs surface.
Active cooling: The process involves the use of absorption cooling or electricity to lower the
temperatures or in changing the phase of the PCM. This kind of approach will need additional
energy to be used in the operations of the fans and the refrigeration systems. The study identified
a passive way of cooling with the other process of lightweight technology as one of the effective
ways to ensure that cooling is achieved. The process has been identified as being cost-effective,
simple and environmentally friendly. Although there are several materials which can be used to
achieve the lightweight roofing construction, the study focused only on the three categories
including use of felt, wood and metal technologies. Every technology has been discussed on its
advantages and demerits.
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REFERENCES
George, P.C. and Mulder, L.A., Chem Link Inc, 2014. Roofing system and method. U.S. Patent
8,701,367.
He, Y., Yu, H., Dong, N. and Ye, H., 2016. Thermal and energy performance assessment of an
extensive green roof in summer: A case study of a lightweight building in Shanghai. Energy and
Buildings, 127, pp.762-773.
Hernández-Pérez, I., Álvarez, G., Xamán, J., Zavala-Guillén, I., Arce, J. and Simá, E., 2014.
Thermal performance of reflective materials applied to exterior building components—A
review. Energy and Buildings, 80, pp.81-105.
Khowaiter, A.O., Saudi Arabian Oil Co, 2015. Self-ballasted, roof-integrated, lightweight FRC
PV mounting system. U.S. Patent 9,194,611.
Naji, S., Çelik, O.C., Alengaram, U.J., Jumaat, M.Z. and Shamshirband, S., 2014. Structure,
energy, and cost efficiency evaluation of three different lightweight construction systems used in
low-rise residential buildings. Energy and Buildings, 84, pp.727-739.
Suzanne, J.M., 2014. Facility and method for storing dangerous materials packaged into
containers. U.S. Patent 8,899,876.
Torkaman, J., Ashori, A. and Momtazi, A.S., 2014. Using wood fiber waste, rice husk ash, and
limestone powder waste as cement replacement materials for lightweight concrete
blocks. Construction and building materials, 50, pp.432-436.
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Wu, Y., Krishnan, P., Liya, E.Y. and Zhang, M.H., 2017. Using a lightweight cement composite
and photocatalytic coating to reduce the cooling energy consumption of buildings. Construction
and Building Materials, 145, pp.555-564.
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