What is prefabrication, Aims of prefabrication, Its advantages and disadvantages, Onsite and offsite prefabrication. Its uses in architecture and construction industry

1. BUILDING CONSTRUCTION &
MATERIALS
PREFABRICATION

2. SYNOPSIS :
1. INTRODUCION
2. AIMS OF PREFABRICATION.
3. ADVANTAGES OF PREFABRICATION.
4. DISADVANTAGES OF PREFABRICATION.
5. COMPONENTS MANUFACTURED IN PREFABRICATION.
6. MATERIALS USED IN PREFABRICATION.
7. ONSITE PREFABRICATION.
8. OFFSITE PREFABRICATION.
9. THE HEMISPHERE –AS AN EXAMPLE OF PREFABRICATES
STRUCTURES.

3. INTRODUCTION :  Prefabrication is the practise
of assembling components of
a structure in a factory or other
manufacturing site and
transporting complete
assemblies and sub-
assemblies to the construction
site where the structure is to
be located.
 Prefabrication deals with the
assembly of buildings or their
components at a location
other than the building site.
The method controls
construction costs by
economizing on time, wages
and materials.
 Prefabrication units may
include Doors, Windows,
Stairs, Room-sized
components, and even entire
buildings.

4. AIMS OF PREFABRICATION :
To speed up the construction time.
To reduce the Labour cost.
To allow the year round construction.
To ensure the precise conformity of building codes, standards and
greater quality assurance.
To reduce the wastage of materials than in On site construction.
To ensure higher worker safety and comfort level than in site built
construction.

5. ADVANTAGES OF PREFABRICATION :
 High Quality products.
Labour related Savings.
Reduced span of construction.
Mass production is easier and quick.
Protected and controlled production
environment.
Potential for lower production costs
and other cost savings.
Ensures high degree of safety.
Independent to adverse weather
conditions during construction.
Light weight products so as they
promote easy handling and transport
and to economies on sections and
sizes of foundations.
Thermal insulation property.
Durability in all weather conditions.
Non - combustibility.
Provides acoustic insulation.

6. DISADVANTAGES OF
PREFABRICATION :
Careful handling of prefabricated
components such as concrete
panels or steel and glass panels is
required.
Attention has to be paid to the
strength and corrosion – resistance
of the joining of prefabricated
sections to avoid failure of the joint.
Similarly, leaks can form at joints in
prefabricated components.
Transportation costs may be higher
for voluminous prefabricated
sections than for the materials of
which they are made, which can
often be packed more compactly.
Large prefabricated sections
require heavy-duty cranes and
precision measurement and
handling to place in position.

7. COMPONENTS MANUFACTURED IN
PREFABRICATION :
Flooring
Roofing
Stairs
Column Beam
Lintel
Walls
Flooring, Roofing,
Beams, Columns,
Walls, Staircase,
Lintels, Sunshades/
Projections are
generally constructed
as Prefabricated
structures and installed
in buildings.

8. MATERIALS USED IN PREFABRICATION :
Concrete Cellular concrete Lightweight concrete block
Treated wood Aluminium Ceramics Steel
Concrete, Cellular concrete, Lightweight concrete blocks. Treated wood,
Aluminium, Steel, Ceramics are the materials generally used in
Prefabricated structures.

9. Onsite PREFABRICATION

10. INTRODUCTION
Onsite Prefabrication is a process where Components of structure are
manufactured at the site or near the site of work as possible.
•The work is normally carried out in open space with locally a valuable
labour.
The equipment and machinery and moulds used in onsite prefabrication
are of mobile nature.

11. ADVANTAGES OF ON-SITE PREFABRICATION :
1. Design Customization
On-site construction techniques help to
have any sort of design customization. In
fact, it let the project team perform limitless
customization. In case of a project,
unexpected delays and issues faced at the
site demands for intelligent design
changes. These changes can be
incorporated in on-site construction
projects.
2. Alteration After Construction Phase
It is always recommended to reduce changes and alteration from the
originally made design of the respective project. Change in design plans
is something that result in project delay. But under necessary situations,
the on-site construction method helps to make changes in the design
plans.

12. ADVANTAGES OF ON-SITE PREFABRICATION :
3. Construction in Tight Urban Areas
Performing construction in urban areas
with a tight population and traffic is a
tough process. It is best to construct
structures in these areas on-site instead
of off-site as it is tough to transport and
assemble building modules in such
congested areas.
4. Easy Renovation
On-site construction helps to add any new structure to an existing
structure or to undergo any sort of renovation. This finally provides a
seamless look to the structure.

13. DISADVANTAGES OF ON-SITE PREFABRICATION :
1. Weather Conditions
The on-site construction is highly influenced by the weather conditions. As
each site of on-site construction is primarily done on-site, each step is delayed
if there are any unfavorable weather conditions
2. Safety Concerns
Compared to off-site or modular construction, on-site construction demands
high safety and precautions.

14. OFFsite PREFABRICATION

15. INTRODUCTION
Examples of off-site fabrication are wall panels for homes, wooden truss bridge spans,
airport control stations.
Off-Site fabrication is a process that incorporates Factory prefabrication and pre-assembly.
The process involves the design and manufacture of units or modules, usually remote
from the work site, and the installation at the site to form the permanent works at the site.
In its fullest sense, off-site fabrication requires a project strategy that will change the
orientation of the project and process from construction to manufacture to installation.

16. INTRODUCTION
There are 4 main categories of Off-Site fabrication, which is often also referred to as
Off-Site Construction.
component systems
panelised systems
volumetric systems
modular systems
modular systems

17. ADVANTAGES OF OFF-SITE PREFABRICATION
1. Project not influenced by Weather
In off-site construction, the majority of the building elements are
manufactured in the factory, hence the weather conditions do not affect
the manufacture. The only site time and conditions affected are during
the assembling.
2. Management of Timelines
The project team at the factory can perform the work simultaneously
with the team at the site so that the timelines can be properly
streamlined.
3. Quality Control
The structural units are manufactured at the factory under controlled
factory settings thus off-site construction produces the final product
with extreme quality.

18. ADVANTAGES OF OFF-SITE PREFABRICATION
4. Less Safety Concerns
The safety concerns and risks are less as a major time of the project is spent
at the factory. Less time is spent at the site for assembling the prefabricated
units.
5. Reduction of Waste and Overall Energy
Considering off-site construction helps to reduce the wastage caused in
construction when compared to on-site construction.
6. Airtight Commercial Buildings
The modular construction techniques develop buildings, especially
commercial buildings that are energy efficient by employing air tight
prefabricated products.

19. DISADVANTAGES OF OFF-SITE PREFABRICATION
1. Suitability Depends on Location
2. Changes in Design and Plans are not possible once the project
Starts
3. Demands Extreme Detailed Planning
4. Customization in Modular Construction is Limited
5. Demands Proper and more communication between on-site
and off – site workers

20. EXAMPLES OF PREFABRICATED BUILDINGS

21. PREFABRICATED STRUCTURES USED IN THE HEMISPHERE

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