Modular building seminar REPORT 2

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1. INTRODUCTION

Modular building and modular homes are sectional prefabricated building or houses that

consist of multiple modules or section which are manufactured in a remote facility and

the delivered to their site of use. These modules are assembled into a single residential

building using either by a crane or trucks.

Modular building has a wide variety of uses. They will either be used for long term

temporary or permanent facilities. Such uses include construction camps, schools and

classroom, civilians and military housing needs and industrial facilities. Modular

buildings are a perfect solution in remote and rural areas where conventional construction

may not be reasonable or even possible. Other uses have also been found for modular

buildings include churches healthcare facilities and retail offices, fast food restaurants

and cruse ship constructions.

At this time modular home today can be built to any specification and any size from a

simple one to a complex one. One of the big advantages of modular construction is that it

is very rapid and it tends to be less expensive than a site-build structure. Manufactures are

not limited by issues like inclement weather and because they have a great deal of

experience, they can put structure together quickly and well. And they tend to be more

earthquake and weather resistance than site build structure.

Modular construction concepts can be applied for all types of buildings such as offices,

commercial, residential, hotels and much more. Recently, modular construction was used

in the UK for projects such as Raines Diary, Murray Groove and the micro-flats concepts.

As shown in the case studies, modular construction can save time in the construction

schedule and therefore may result in savings. Also, the generation of construction waste

is reduced on-site due to the off-site prefabricated modules being transported to the site

fully fitted out, hoisted and assembled

2. THEORY

There is an age-old analogy in construction circles regarding how building modules are

much like the basic, living cells found in nature. Take the brick for example. A brick is a

man-made module of elegant simplicity that has been used by home builders for

thousands of years. Although it seems lifeless, assembled piles of bricks stuck together

Department of Civil Engineering Seminar 2014

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with mortar develop into protective structures, just as cells labelled “skin” to combine

and protect our bodies.

Recently, modular building modules have evolved into larger and

more complex cells born to encapsulate smaller functions. In modular design, these

modules now incorporate many of our life support systems: heating, ventilating, air-

conditioning,waterdelivery,wastesystems,electricity,security,andmuchmore.

And, just as tiny organisms have evolved, so have the small brick modules

formerly used in the buildings of old. Now, sheets of plywood, glass & metal panels and

floor joists (to name just a few) are components that have become pieces of our

sophisticated environment.

3. STANDARDS AND ZONING CONSIDERATIONS

Typically, modular dwellings are built to local state or council code, so dwellings built in

a given manufacturing facility will have differing construction standards depending on

the final destination of the modules. Steel and/or wood framing are common options for

building a modular homes. Modular home designs can be customized for local zoning

codes. For example, homes built for final assembly in a hurricane prone area can have

additional bracing built-in to meet local building codes.

Some US courts have ruled that zoning restrictions applicable to mobile homes do not

apply to modular homes since modular homes are often assembled with a permanent

foundation. Additionally, in the US, the Uniform Standards of Professional Appraisal

Practice allow site-built homes to be used as comparators to modular homes in real estate

appraisal; thus, modular homes can in some cities and counties (depending on local

ordinances) be evaluated the same way as traditionally built dwellings of similar quality.

In Australia Manufactured Home Parks are governed by additional legislation that does

not apply to permanent modular homes. Possible developments in equivalence between

modular and site-built housing types for the purposes of real estate apparels financing and

zoning may increase the sales of modular homes over time.

4. BUILDING STRENGTH

According to manufacturers, modular homes are generally designed to be initially

stronger than traditional homes by, for example, replacing nails with screws and adding


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glue to joints. This is supposed to help the modules maintain their structural integrity as

they are transported on trucks to the construction site. Despite manufacturer claims that

the modular home is initially built to be stronger than a traditional home, it is difficult to

predict the final building strength since it needs to endure transportation stresses that

traditional homes never experience.

Typically, a modular home contains about 10% to 20% more lumber compared to

traditional stick-built homes. This is because modules need to be transported to the job

site and the additional lumber helps keep them stable.

5. CONSTRUCTION PROCESS

Modular components are typically constructed within a large indoor facility on assembly

lines. Such facilities use an assembly line track to move the modules from one

workstation to the next. Independent building inspectors are on site to supervise the

construction and ensure that all building codes are adhered to during assembly.

The modules that will combine to form the house are assembled off-site in a factory.

These modules can take one to three months to be constructed but often take as little as

10 days actually to construct when they are first started. Then they are transported to the

building site where a crane is brought in to assemble the modules together. The

placement of the modules together generally takes several hours or days. Once

assembled, modular buildings are essentially indistinguishable from typical site-built

homes.

Once a potential homeowner has decided to go with a modular home, there are a few

steps to take that are relatively consistent regardless of which modular home building

company one is working with. First a homeowner must select a modular home factory.

The majority of manufacturers are located on the East Coast, and some are very specific

as to what states they will ship their homes

.

Since it is usually necessary to include a local builder or


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developer in the process it may be helpful to consult with this party for advice on

manufacturers. Many local developers have established relationships with certain

manufacturers, so this is a good place to start. After a local developer and

manufacturer have been decided on, the homeowner must choose a floor plan and

select from a wide range of options. When these decisions have been made and an

initial contract is signed, the manufacturer's engineering staffs overlook the plans and

the factory can go to work on constructing the home. Once the manufacturer has begun

building the home in the factory, it is usually just a matter of weeks before the units

are ready for transport. As the work in the factory is taking place, on-site construction

of the home's foundation by the local builder is being done to ready the site for the

arrival of the home. Because the foundation is being laid on-site as the home is being

built in the factory, the overall construction time is dramatically reduced. The modular

home is then shipped to the site on flatbed trucks. The units are then placed by crane

onto the foundation, and the entire home is fastened together. At this point, the amount

of time until the homeowner can move in depends on a number of things. There are

plumbing and electrical tie-ins to address as well.

Fig .1: Bulk material used for modular building


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Fig .2: Wall attached to floor

Fig .3: Assembly of the building—exploded view showing the individual modules


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Fi

fig .4: Construction of each module by crane in the site

Fig .5: Modular home after construction

6. SURFACES AND FINISHES

Modular buildings can be assembled on top of multiple foundation surfaces, such as a

crawl space, stilts (for areas that are prone to flooding), full basement or standard slab at


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grade. They can also be built to multi-story heights. Motels and other multi-family

structures have been built using modular construction techniques. The height that a

modular structure can be built to depends on jurisdiction but a number of countries,

especially in Asia, allow them to be built to 24 floors and possibly even more.

Exterior wall surfaces can be finalized in the plant production process or in the case of

brick/stone veneers field applications may be the builder’s choice. Roof systems also can

be apart of - separate from - applied in the field after the basic installation is completed.

7. EXAMPLES OF MODULAR CONSTRUCTION

7.1. MARRIOTT COURTYARD HOTELS

The USA’s Marriott Corporation shows offsite fabricated modular units from

manufactured Kaplan for its courtyard hotel chain. The units comprise two bedrooms

separated by a corridor and measured 18.5m by 4.1m, using a rectangular hollow steel

section frame with steel/gypsum board walls. Even on the first prototype hotel, the offsite

prefabrication approach saved 60 days on the construction programmed, which Marriott

considers in worth around US dollar 1 million

Fig.7: Marriott Courtyard hotel

7.2 ABN/AMRO BANK EXTENSION, AMSTERDAM


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This bank needed 600 to 700 people space. Today the bank occupies 100,000 sq. ft. class

A corporate office space, constructed from prefabricated modular units. The four storied

building has a total GFA of about 1, 15,000 sq. ft. The building was constructed using

675prefabricated modules to create 710 workspaces the floor was made of concrete and

the ceiling height was about 9 ft. In future it is intended that the manufacturer De Meevw

will purchase back and remove the building after a minimum of 5 years should the bank

want to sell it. The building was designed to a last period of 10 to 25 years or more with

proper maintenance. The total project cost were 31% lower than leasing conventional

office space

Fig.8: ABN/AMRO Bank extension

8. ADVANTAGES

Modular buildings are very affordable because of the factory construction of these

buildings. They are a very cost effective compared to conventional construction. These

units are typically constructed in an enclosed facility; therefore weather is not a factor in

the construction time line. Material delivery fees are also out of the equation because an

ample amount of material will always be available at the facility, as opposed to being

delivered in limited quantities to the job site, nearly eliminating construction delays, and

theft of building materials from the site.

Such dwellings are often priced lower than their site-built counterparts and are typically

more cost-effective to builders and consumers. These new homes can be constructed in


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less time than it takes to build a home on-site. Manufacturers cite the following reasons

for the typically lower cost/price of these dwellings:

Speed of Construction/Faster Return on Investment - modular construction allows

for the building AND the site work to be completed simultaneously, reducing the

overall completion schedule by as much as 50%.

Indoor construction. Assembly is independent of weather which increases work

efficiency and avoids damaged building material.

Favourable pricing from suppliers. Large-scale manufacturers can effectively

bargain with suppliers for discounts on materials.

Ability to service remote locations. Particularly in countries such as Australia

there can be much higher costs to build a site-built house in a remote area or an

area experiencing a construction boom such as mining towns. Modular homes can

be built in major towns and sold to regional areas.

Low waste. With the same plans being constantly built, the manufacturer has

records of exactly what quantities of materials are needed for a given job. While

waste from a site-built dwelling may typically fill several large dumpsters, waste

from a modular dwelling generates much less waste.

More environmentally friendly construction process - modular construction

generates less materials waste and less site disturbances than comparable site built

structures.

9. DIS ADVANTAGES

TRANSPORTATION COST

Need of modular shipment to the project site for permanent installation.

Increased shipping cost for the project.

Requirement of double handling as equipment and materials are shipped

to the site.

MODULE SIZE LIMITATION

Different restriction for each mode of transport trucks, train.

Design must consider dividing modules according to transportation

constrains.

TRANSPORTATION ACCESSIBILITY

Modules must be shipped to the site


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Access site constrains should be carefully considered, especially in dense

urban areas.

10. MODULAR HOMES VS. MOBILE HOMES

1) The codes that govern the construction of modular homes are the exact same

codes that govern the construction of any site constructed home. In the United

States, all modular homes are constructed according the International Building

Code (IBC), IRC, BOCA or the code that has been adopted by the local

jurisdiction. Mobile homes (manufactured homes) are constructed according to

the HUD Code and are generally considered lesser quality.

2) The materials are the same as site constructed homes. Wood frame floors, walls

and roof is the most typical. Some modular even included brick or stone exteriors,

granite counters and steeply pitched roofs. All modular are designed to sit on a

perimeter foundation or basement. Mobile homes are constructed with a steel

chassis that is integral to the integrity of the floor system.

3) Lending institutions and appraisers consider as they consider a site built home,

with the same life expectancy and modular home the same as value. Mobile

homes often require special lenders.

Most companies have standard plans. However, all modular buildings can be custom built

to client’s specifications. Today's designs include multi-story units, multi-family units

and entire apartment complexes. The negative stereotype commonly associated with

mobile homes and has prompted some manufacturers to start using the term Off-Site

Construction.

11. ENVIRONMENTAL BENEFITS DURING THE CONSTRUCTION

The main environmental benefits during the construction operation are derived from the shorter construction period,which lessens the impact on the local environments. Waste isdrastically reduced because of efficient factory production, and the reduced damage or use of packaging materials on-site.There are other local environmental benefits of theconstruction operation, which are identified as follows:


http://en.wikipedia.org/wiki/International_Building_Code

http://en.wikipedia.org/wiki/International_Building_Code


Site installation of the modular units is a rapid and quiet operation that can be done ‘just in time’, with no requirement for site storage or additional noisy equipment.

The delivery and installation of the modular units can be timed to observe any site working or road traffic constraints.

The delivery of a large number of relatively small amounts of site materials is much reduced.

Less waste is created so dumping of material waste from site is much reduced to less than 30% of a conventional project.Foundation excavation is minimised and there are fewer potentially wasteful site activities.

Materials are used more efficiently, with considerable economy of use in production than is achievable on site.

The main construction operations are less disruptive to adjacent or connected properties in terms of pollution and associated nuisance, etc.

11.1 ENVIRONMENTAL BENEFITS IN USE

The environmental benefits in use concern the high level of performance that can be achieved economically, as follows:

Good acoustic insulation is provided due to the separation between the modules. Good thermal insulation can be provided easily in light steel framing by creating

a ‘warm frame’.These buildings are very efficient thermally, leading to reductions in energy use and consequent CO2 emission.

Modular units are very stiff and strong, due largely to requirements for lifting and transportation, and therefore have a solid ‘feel’.

All light steel framed structures require minimal maintenance and no call-backs for shrinkage, etc.

11.2 ENVIRONMENTAL BENEFITS IN REUSE

The benefits in terms of re-use are: Modular buildings can be extended easily (or reduced insize) as demand changes. Modular units are fully relocatable at modest cost, withconsequent reduced

energy cost in dismantling, and nowastage of materials. Long-term use of scarce resources is reduced.

12. CONCLUSION



Modular buildings are a perfect solution in remote and rural area where conventional

construction may not be reasonable or even possible. Other uses have also been found for

modular buildings include churches healthcare facilities and retail offices, fast food

restaurants and cure ship constructions. According to manufactures, modular homes are

generally designed to be initially stronger than traditional home by, for example,

replacing nails with screws and adding glue to joint. The generation of construction waste

is reduced on-site due to the off-site prefabricated modules being transported to the site

fully fitted out, hoisted and assembled. Therefore modular buildings are good for

construction nowadays.

REFERENCES

1) Automated post simulation visualization of modular buildings production assembly

line,Automation in construction,Science Direct

2) Hybrid light steel panel and modular systems,R.M.LAWSON,Thin walled

structures,Science Direct

3) The benefits of modular construction,by DEVIN M.REFFIT,renal Business

today,October 2007

4) DonShulman”Reality Development Associates Announces Expansion” Easton

Journal

5) Osama M Mohson, Paul J Knytl, Basel Addulaal, Jack Olearezyk and Mohammed Ali

Hussein, “Simulation Of Modular Building Construction”,University Of Alberta

Edmonton Journal.

6) Chehayeb.N And Abourizk.S, 1998,”Simulation-Based Scheduling With Contours

Activity Relationships,”Journal Of Construction Engineering And Management,

ASCE Civil Engineering Journal.




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Modular building seminar REPORT 2