International trends in construction technologies and the future of housebuilding

53

INTERNATIONAL TRENDS IN CONSTRUCTION TECHNOLOGIES AND THE FUTURE OF HOUSEBUILDING David

Gann and Peter Senker

This article technologies

draws on international against the background

evidence on changing construction of future trends in UK housebuilding.

There is evidence that housing construction in the UK is inadequate to meet social needs. Major changes in housing finance policy are probably needed to deal with this problem. It is suggested that shortages of traditional skills, together with needs to comply with stringent environmental regulations, may well lead to future housing programmes depending on extensive use of new technologies. Industrialized housing construction techniques have been used successfully in some countries, and the article adduces evidence from this experience. However, in the absence of adequate investment in R&D and training of construction workers, there is a grave danger that industrialized building could result in the construction of poor-quality, expensive-to-maintain housing, as it did in the UK in the 1960s. The utilization of new housing technologies needs to be evaluated in a broad context in order to determine the priorities for R&D, changes in production processes and training programmes.

The

materials

and

changed

significantly

occurred

gradually

existing

in

Since

most

has been gained

in the

office

boom

used 20th

in

time,

of the

I But

radical

changes

housing

of

But

production

these

have

changes

have

and adaptations

in technologies

to

have been

construction.

of industrialized

commercial

late 1980s.

house

many

changes-alterations

to industrialize

of the experience in large-scale

conventional

century.

incremental

At the same

in attempts 1967,

the

through

techniques.

implemented UK,

components

building

and industrial

substantial

techniques

construction,

experience

in the largely

of industrialized

David Cann is Research Fellow, Science Policy Research Unit, and Peter Senker IS Senior Fellow, Science Policy Research Unit, Mantell Building, University of Sussex, Falmer, Brighton, East Sussex BNI 9RF, UK (Tel: + 44 273 686758; fax: + 44 273 685865).

FUTURES January/February

1993

0016-3287/93;‘01053-13

@ 1993 Butterworth-Heinemann

Ltd

construction techniques applied to housing as well as to commercial and industrial construction has been gained abroad. This article reviews this experience in the hope that it will stimulate discussion of the role of new technology in housing, and help to guide R&D, construction technology strategies and training policy. There are three pressures which may give rise to the need to reconsider housing technologies: the need to construct high-quality, low-cost housing quickly; the need to meet higher environmental standards; and the potential demand for installation of a wide range of information technologies (IT). Traditional brick/block construction processes are slow and inflexible. New technologies may offer potential for overcoming constraints on increasing the rate of new construction imposed by shortages of labour with traditional skills. But it may be more difficult to introduce new technology into UK housebuilding than in some other European countries. The profitability of housebuildin~ is much more volatile in the UK than in France and Sweden, and this makes long-term planning difficult for UK firtns and induces conservatism.L Nevertheless, the prospect of a low-inflation, high interest rate economy during the 1990s could stimulate UK housebuilders into considering changes in production technologies, rather than relying on profits from exploiting land banks.

Housing shortages, environmental

concerns

and IT in the home

In 1985, the Inquiry into British Housing’ classified housing problems into four categories: a housing shortage, reflected in a high number of homeless families living in short-term accommodation such as ‘bed and breakfast’ hotels; deteriorating housing conditions in the private sector, both rented and owner-occupied; badly designed, difficult to maintain council estates in which ethnic minorities and the poorest tenants were concentrated; and the compartmentalization of housing into sectors and tenures which deny choice, leading to polarization of communities and generating divisiveness and tension. Two major factors were identified as underlying these problems-a heavy financial bias towards owner occupation and an unhelpful rigid financial and organizational framework. These problems persist and a recent report confirmed that construction of new homes is unlikely to be sufficient to meet social needs.j In the next several years, lower birthrates are likely to result in a sharp decline in the demographic pressure on the housing stock from new household formation. However, other factors such as homelessness resulting from the backlog of shortages, and the likelihood of more people leaving parental homes result in the need for a substantial housebuilding programt~~e. Few typical working households can afford to buy their own homes’ and studies which have examined the requirements for subsidized housing have shown the likelihood of increasing shortages.” The trend to smaller households and people living alone will require an increase in the number of small units. More old people, more single parent families and fewer larger families also serve to make the existing housing stock less appropriate to future needs. The growing proportion of elderly people together with better provision for the disabled will create needs for increases in sheltered housing schemes.’ Growing awareness of the impact of buildings on the environment and of the environment on buildings has resulted in tighter energy regulations, and Green Audits. These aim to assess the impact of buildings on global atmospheric pollution, on the local outdoor environment and depletion of resources, the influence of

FUTURES January/February

1993

international

buildings

on the health,

change third

trends in construction

on

Green

Audit

significant

using

larger

soon

brick/block

that this

blocks

example, niques

the

to achieve

construction The

halls

of electronic programmes

sustained

pace

being

in what

made to reduce

structure

and fabric

may emerge, made

Industrialization Attempts

on-site, left

to

thicker

is

of walls

insulation

But

requires

home

may

housing, for

such

for tech-

reorganization

has

technologies,

known

as ‘smart

of the

building

is the

Open

increasing

electronics

some

of

rapidly. firms

which

find

attempts

are

While

of these

technologies

Building

on the

prefabricated

services

have

will

homes’.

that new integrated

and other

example

been

consumer

of the installation

are installed

systems in factory-

System

developed

in four

phases

at the

in the UK

housebuilding

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and was followed

by their of such

a considerable

building

techniques part

be performed

have

began with

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of industrialized

the effectiveness

rule out

insulation

in low-energy

University.

these

of housing construction

century.

development

cavity

in the Netherlands.

to industrialize

mid-19th

for homes

and the construction

used

Anglia

in the

it is likely

cabling

One

of Delft

in

become

of homes,

components.

University

in future,

out by leading

the impact

in which

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to reveal

skills.

carried

have

levels

to accommodate

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change

of climate

launched

are likely

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on more than a local basis

use

application

unless

at East

and additional

of

insulation

have been

of residence

Large research the

cavities

and the impact Establishment

assessments

55

of housebuilding

of construction.

higher

techniques

success

process

methods

construction

wider

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new

Such

may be inadequate

and

be necessary.

Research

housing.8

stipulating

and the future

of occupants

Building

in traditional

regulations

the use of traditional

the

at new

inadequacies

It is likely

and safety

In 1991,

aimed

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comfort

buildings.

technologies

occurred

the standardization

in factories. systems

have shown

of the

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much

ways.

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phase

labour

finishing

the

included

in the 1960s.

that while

labour-intensive

in traditional

third

used

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of components

time

gains

of

was saved

of internal

productivity

the

Studies work were

was rarely

achieved.9 The produce and

to

stimulus

to

housing

after

turn

factory-made the

1960s

to use prefabricated building public

systems sector

promoting products

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drew

world slum

heavily

industrialized

their

influencing

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generations

apartment

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1963

struction

and there

to

by the

new

Manufacturers of the Modern introduced

of industrialized during

played

important

periods

of

roles

in

and marketing

architects

of

in decisions

research

movement

of

scarcity

influence

factory-made

of local authority

producing

programmes

techniques:

the development

to

scarcity,

uses

building

building

need

materials

(such

of new

as Cropius,

components

into

and planners.1°

blocks

and 1965, was

FUTURES January/February

Fuller)

and

any cost. The development

through

Architects

and Buckminster

factories

by government-funded

systems

provided

was again an important

investment.

and components.

was

of labour

and new town

industrialized

at almost

Le Corbusier designs

armaments

on

was sponsored

infrastructural

at times

clearance

and of materials systems

methods

wars

wartime

housing.

craft skills

industrialized

two

redundant

also

traditional

use

UK governments concern

1993

whether

set increasing they

could

targets

for

be attained

housing

con-

in the face of

perceived

shortages

reducing produced

building

especially

1962

explosion

that

Ronan

on 16

May

had been banned

cheaper

flats

families

living

parents

and This

and this

reinforced

of tenders

Timber-frame

replaced

other

regions

storeys.

approved

such

their

major

work

was

built

not

housing

Prefabrica-

1966,

growing

resulted

objections

strain

were

to

imposed

increasingly

against

high-rise

After

flats

new technology became

of additional there

on

recog-

was

in

discredited

subsidies

a rapid

fall

per in the

flats.”

when

also can

waiting

be

external

replaced

appearance

I5 Shorter

reduce

site

their

to meet variations In contrast, load-bearing floorboards,

the

Modern

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bricklayers

to

elimination

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by

nailing

identical also

and

stairs

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use

permit

payments

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can get on with of

timber-frame

indoors.

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plasterboard

to that

brick/block

of dwellings housing on capital

example,

sheets.

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constructed developers

to

borrowed,

and

swiftly.

building

external

The

trades

standard

times

more

house

finish.

are

construction

per house.13

trades

in

timber

structures

over

weeks

but

dominant

timber

other

for

and interest

century,

had plentiful

construction

the

costs

which

five and eight

of

the 18th remained

use of timber-frame

are erected

is virtually

in demand traditional

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speed

to between

construction

overhead

there.

rapidly.

in

Timber-frame

and Scandinavia

timber-frames

encourages

in the UK before

concentrated

on site

improvements

traditionally.

rafters,

were

and supervision

frequently

The

children

prejudice

of building.

America

18 to 24 weeks

without

techniques finished,

it

need had led to far more

by the ending

for high-rise

as North

because

plasterers

six storeys: at the inquiry

system

were

envisaged.

for

was traditional

innovation

from

achieved

the

in 1967

it as the main form

and

methods

been

system-built

over

and can be assembled

facilitates

had

reflected six

there

of housing

a well-justified

construction

brick

supplies,

built

in Denmark

construction

Timber-framed

light

was

London

construction. housing

to

a gas

of the panels

that

high-rise

failures,

problems

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of blocks

some

a view after

than

given

in workmanship

emerged

pressure

than

episode

rejection

The

blocks

developmental

flat in respect number

technical

grounds.

in the UK.

of more

than traditional

used in 1960s

the

construction

in Greater

evidence

holding

evidence

of houses. with

of condensation.‘?

to extensive in such

The

in

apartment-

collapsed

of flats

were deficiencies

elements

on social

partially

held that

extensively

production examined

for buildings

nor quicker

used

of high-rise

had been developed

in the USA.

that the joints

and problems

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rarely

six storeys

Furthermore,

neither

joints

high-rise

although

This

of factory-

of housebuilding,

were

were

which

the aim of

use

was widely

mode

exceeded

one of 26 blocks

and that there

tion of large structural in leaking

building

with

the

view

construction

systems

Larsen-Nielsen.

there,

construction.

was probably

the

The

dominant

of flats

Point,

was

increasing

techniques

the

production

concluded

strong

for

continental

above

the explosion

sufficiently

the

Industrialized

many

1968,

was adopted

by

mechanization.

especially

system-the

building skills

become

sector.

period,

and used extensively

nized.

rapidly

196Os,

UK.

one such

during

and on-site

to 1967,

During

in the

after

craft

would

In the early

using

Systems

on-site

in the public

period

blocks.” use

labour.

for

components

systems the

of site

requirements

internal

is dependent walls

first,

and window-frames

on bricklayers

with

carpenters

after bricklayers

to build fixing

up

joists,

have done

FUTURES January/February

1993

international

their

work

carpentry frame

and

other

work

has

removes

semi-skilled In America

cold

where

policy

30 million

building

In this

period,

reduction

about

in the

components

necessary timber-frame tially large

number

faults

of faults

Several

their

lack

including

liable to lead to gross

long

periods.

able

Houses

walls

locations

supervisors

and

inspection

was inadequate

Timber-frame build

housing

These

frames

techniques into

schemes

and

housebuilders. housebuilding,

not

relative

remaining

ties

in vulner-

preservative.

Site

construction

and

of construction.r9

in the growing Associations

number

and

replenishable

such

wet for

foundations,

with

for speed

against

and windows,

of the timber

treated

utilizing

vertically

barriers

to their

a

design

movement gutters

in

identified

Common

of timber-frame

popular

fell substanin a ‘World

adequate

and some

been

of insulation

of

execution.

linked

Housing

the

Establishment

and the structure

of pressure

lacked

the reputation

housebuilding

of flashings,

experience

by

which

condemnation

for

inadequate had

some

impaired

to provide

effectively

have become

methods

the and

as recycled

of self-

Cooperatives.

softwoods.

Some

newspaper

blown

cavities. Questions

damp

UK

because from

remain

climate. new,

draughty.

are needs

to house

is need for

critical

elements

theless,

defects houses

of workers

frames.

this.

special in the

training

FUTURES January/February

for

construction houses

in inclement

1993

damp

interstitial

site

workers

process on-site

consist

which

and effective

quality

both of parts

causes

inspection

is inherently that

less

made of the right

and inspection

on

and

and rot arising

condensation

to ensure

primarily

sealed

in designs,

and meet

occur

of thousands

weather.20

tightly

construction

supervision

in the

housing

penetration

of site operatives

timber-frame proper

construction

in new

to be more

against

need to be included

While skills,

of workmanship

tend

to prevent

Good training

building

because

often

barriers

of timber-frame

have increased

dwellings

installed

to achieve

mical in traditional

suitability

for safeguards

rain. Vapour

are required

the

of condensation

and properly

damage

there

over

Risks

energy-efficient

There

driving

materials

frame

new

in

declined.

materials

private

were

of private

press

are ‘environment-friendly’,

utilize

resulted

in the UK. With

in private

seriously

provision

sponsored

built

a

in govern-

construction

with

and

as a result

methods

were

houses

penetration

rot

up

in North

was used extensively

of timber-frame

specification

or no previous

II.”

set

in 1983.18 which

not

to

Changes

Research

were

to

it with

in the late 1960s

increased

construction

often

liable

had little

replaces

War

products

and failure

water

and sheathings

years, Timber-

particularly

UK Building

of

poor

were

and

housing

houses

their

in the

The

in design,

were

between

public

proportion

and cladding,

faults,

many

government

method

suppliers

built

reports

included

the frame

of

UK

This

when

led to failures

bad

sites

housing

timber-frame

programme.

identified

between

use

of houses

This

after

television

1976 market,

building

For

increasingly.

countries,

World

construction.

sector

construction:

by 1984

since

the use of timber-frame

the firms

expertise.

the

to low-density

until

the

from

in other

350 000 timber-framed

public

for a quarter

Among

prompted

had been built

promoted

accounting

work

housing

high-rise

the late 197Os,

Action’

winter

programmes

mechanized

57

factories.

use of timber-frame

public

of housebuilding

in sequence.16

and

carpentry

timber-frame

away from

and the future

carpentry

off-site

remaining

the

technologies

following

moved

in automated

to study

in increased

fire.

most

1962-63,

During

trades been

workers

commission ment

trends in construction

econo-

is essential they

standards.

traditional

and

understand Never-

and

put together

timber-

by teams

58

lntrrnntionai

trencis in construction

Recent developments There

are three

construction increased

major

trends and

and control

ponents

and new

of which

component

there

Despite

its chequered on-site

ments

often

techniques-in higher

prefabrication

Development panels. ture

production scope

of

Industrialized the

bedrooms

using

systems

the failure

construction of

the

of newer

the possibility used more

of meeting

for the produc-

could

to facilitate

environ-

use

be developed

extensive

and

the

of systems

pressures

building

to

based

use of

industrialize

on large heavy

is increasingly

based on ‘open systems’

components.

Recent

may facilitate

prefabrication

increasing

programmes.

prefabricated after

and costs;

and bathrooms

products

now for

to increase

that factory

techniques

of

and quality.

and

housing-offers

and smaller the amount

available

means

production;

Moreover,

kitchens,

modularization

methods

for

their

housingbuilding

continued

and

for

range of prefabricated

in future

construction

sites

efficiency.

fitted

time

com-

of prefabrica-

importance

means

construction

of site

modular

systems,

is of growing

the are:

the use of IT

increasing

efficiency

and equipment

timber-framed

of energy

to make a wider

of improving

prefabrication

that

as one of the principal

than

buildings;”

large modular

method

both

These

the development

of prefabricated

held view

on-site

affect

on the development

categories:

history,

particular

tion of prefabricated

within

including

mainly

components

better

standards

functions

is a widely

and to reduce

of building

are

focus

likely

it is perceived

sophistication

themselves.

processes,

main

There

is the most

productivity

We

are two

subsystems.

reasons:

which

buildings

and the development

prefabrication several

technologies

product-the

and control

materials.

of hourehnilding

technologies

construction

technologies;2’

,lnd the future

in construction the

use of IT to monitor

automation tion,

in construction

process

to monitor

tee-hnologies

a wider

choice

in the assembly

architec-

developments

of components,

of a greater

in

factory

increasing

range of housing

the styles

and types.

Prefaahrication in oft& Prefabricated the

late

modules

modules

1980s

used

small, are

have

been The

expand

areas

delivered

bathroom

plugged

use

spaces.

to

fully

their

delays:

position

module

manufacture. market

industry,

they

construction

For

wet

are

those

kept

is a

and

the

services

have had to queue very

standards

in situ. After

and

up

prefabricated

high

produced

locked

areas

sealed

to

of they

prevent

over.

is opening

example,

firms

a variety

coachwork

to

of

toilet

involve

trades

In contrast,

often

from

of toilet methods

trades

boom

prefabricated

traditional

to work.

is handed

modules

come from railway

example,

projects, turn

fitted-out

the building

of prefabricated their

ing the nuclear

or-site

to

In some

for

into

until

For

trades-including

waiting site

costs.

are indistinguishable

and theft into

rise

16 different

cramped

in the UK office construction

reduce

tradition4

giving

to

specification-some damage

and

because

up

particular

modules

time

spot,

of

trades-in

were used extensively

save

trouble

coordination outside

to

were

notorious

construction

the

way

for

operating

new

in the

of engineering

industries UK

toilet

backgrounds

and the temporary

to and

includ-

accommodations

industries. Nevertheless, modules

appear

labour-intensive.

British

manufacturing

to be slow

to innovate.

Firms

do not invest

and Factory

heavily

engineering production

in R&D

firms

which

produce

in the UK is extremely

and they

have not developed

FUTURES January/February

1993

International

automated strategy

production

is partly

unease

trends in construction

processes.

due to their

technologies

The

and the future

reluctance

concerns

over

in the UK about the appearance

to

market

of factory

pursue

a more

instability.

produced

of housebuilding

innovative

In addition

finishes

59

there

is

such

as plastic

is driven

by firms

walls.

Intelligent

building technologies

At present, seeking they

most

water

infra-red

firms

such

in attaining

safety

development

wherever

the

have the potential level

in the

for

derives

that

from

rather

market

from

than

from

the

range

a smaller

is to create is very

to

weak. 24 This

interests

principal

demands

drive

more

or in

thrust

for

of

luxuries,

to use new techno-

in promoting

aim of satisfying

house.*j

for example

on energy,

the

and meet

and

of a house

be in the

expenditure

and

systems

to residents,

people,

The

for metering

in any part

happens

which

needs.

of security

benefits

or infirm

suppliers’

systems

equipment

consumer

elderly

demand

component

a wide

technologies

and military

include

of offering

of comfort home

from

industrial

electronic

and commercialization

and it appears products,

consumption; which

in Europe

can profit

seek to adapt and apply

from

a given

increasing

they

to meet consumer,

through

systems

IT to housing

in which

and energy

techniques

be controlled

While

to apply

markets

developed

which

controlling

logy

new

have already

technologies

can

of the effort

to create

basic

markets needs

for

for

their

adequate

housing.

The use of new technologies French

and German

modular

designers

construction,

of curtain

walling

outside the UK

in office

and the provision

through

use

There

are, however,

commercial

Industrialized countries

used

for

because

as they

different the

construction.

much

interest

in these

means

that little

countries

could

that

can be gained

curtain

and this

in

and installation

argued

Nevertheless,

to

1850

In

walling

has

be indicative

lifts They

areas

more

on

countries.

construction

of

wooden

buildings,

FUTURES January/February

1993

politically

discredited

in

of the 1960s

and they

are

prefabrication

and

cost in the

cheaper

is

is often

accumulated

construction

by small there

become

used

easier

considerable

of installation. mid-1980s

than

and Japan.

extensively than

in

example,

in

For

for

use

conventional

on-site

expertise in residential

types,

and more

in the past 5 years.

industrialized

housebuilders

not

modules

in Scandinavia

the failures fabrication

developed

25 Timber-frame

practised

and medium-sized

time

are much

of Japanese

heavily

have

the

have been installed

Many

did after

Scandinavia,

firms were

of the use of prefabricated

and housing

and off-site

reduce

work.

examples

techniques

Scandinavian

refurbishment

built

skills

in France,

projects

did in the UK

is harsh

modularized

European

numerous

reasons.

climate

techniques

Sweden,

relies

extent

construction

construction

those

than

It is often

construction.

to a limited

not shown

in the production

trend.

for both

these

have

leads

of high-calibre

of modularized

been used for housing a future

Germany

construction.

good training the

and contractors

although

have

building is the

to

been meet

traditional

firms

using

still

produce

highly

have been many

industrialized, housing

method skilled

recent

Japan

than

of Japanese

craftsmen.

a high proportion

and

needs

While

do

house small

of conventionally

developments

to introduce

hO

International

factory

trends in constructIon

produced

prefabricated using

timber-frames.

panel

These

production.

The

cuts

approach

produces

then

erect

these

appearance timber

joints,

take two forms:

pre-cut pre-cut

After

1970,

and Sekisui

marketing.

heavily

Toyota,

while

thousand

prefabricated

market

to affluent

households

working-class

housing.

bricated

These

producers

half the total because

this

mies

houses

units

Tokyo

are also

used

Games.

in recruiting

time

frames

and

and

extensively. use

appropriate

minimize

cladding

These for

on-site

complications

on-site.

toilet

modules

are used extensively

In Japan such

units

are now

being used

units

and in housing

(bath,

grown

toilet

to nearly

and

256 000 units.

(bath and wash-basin) Modules zis,

exercise

market

rose

rooms and

offer

methods

to meet extensive

indicates

that

offering

them

to

and

the

846

Growth

attempt

Japan

dwellings. bathroom market

000

to people

use

units

units. of Jacuz-

in these

success to

had

of double

the installation

Japanese

for rental

inferior

by

pressures

3-in-1

the prefabricated

the

the 1963 driven

of new detached

1989

than

gadgetry. The

for

occupancy

the number

include

conceal

needs for housing

mean

and

pro-

and bath-

Scandinavia

By

econo-

factory

Japan,

over 49 000

to more

housing

of styles.

in

labour

in Japan.

100 000

effectively

range

products

need not necessarily

In 1973,

sold

of large

from

toilet

in hotels

in multiple

microelectronic

which

a wide

prefabricated

under

only

the construction

the same years,

in detached

and various changes

work. were

used

In both

in both

Between

from

for installation

is due to product bathrooms

refurbishment wash-basin)

the

growing

construction

prefabricated housing

first is

Firms

market.

Prefabricated

were

housing

.55%

produced.

benefit

housing

to be

around

the production time

are not

construction.

The

of each house

of housing

through

and prefa-

per year-nearly

prefabricate

and style

of scale

high-density

panel systems.

units

of a differentiated

housing

Their

to

and at the same

the needs

in Japanese

Olympic

problems

economies

structural

elements

in design

constructs housebuilders

produced

up to 90%

opted

Daiwa

and sophisti-

as supplying

or concrete

for

have

components

meeting

Prefabricated duced

flexibility

able to achieve

of standardized

firms

National,

major

industrially

steel-framed

It is possible

but

greater

of scope-by

room

output.

Heim,

five

as well

use

70 000

Prefabricated

housebuilder,

The

steel-framed

around

Carpenters has a similar

of houses

volume

year.

they

a

automated

hours.

which

methods.

Sekisui

centres

markets

are either

factories,

allows

are therefore volumes

in urban

In both

housing

in

per

new,

in the UK.

production

a large

houses

three

and

all the joints Traditionally

The

housing

traditional

used

in factory

it is not

manufacture

UK

prefabricated

in about

the big five housebuilders_Misawa,

several

largest

using

timber-frames cutting

in factories.

to produce

to those

pre-cut

per house.

for one house

produced

of housebuilding

involves

tools

30 days

on site

is similar

Kawa-invested

parts.

about

timber frames

construction

method

machine

taking

and feel to those

panel

cated

these

and the future

pre-cut

computer-numerically-controlled

carpenter

save

technologies

markets

nature

of the

in selling

up

industrialized

of modest

means

products.

The pros and cons of prefabrication There

are a number

an industry where received

those

which

of drawbacks is not

involved

appropriate

to the use of prefabricated

organized

from training.

in an appropriate

design

to

L(1 For

these

management reasons,

housing

manner and

many

elements

to use

installation

experts

believe

them

in and

have

not

that

the

FUTURES January/February

1993

international

TABLE l l l

0 l

o

1. FACTORS

trends in c~n5tructj~n

TENDING

TO PROMOTE

technologies

and the future

THE USE OF MODULARIZED

of h~use~uilding

67

CONSTRUCTION

Improved quality can be secured through factory production in controlled environments. Manufacture, delivery and installation are less dependent upon the weather. Faster on-site construction times can be achieved because problems of co-ordinating the work of a large number of trades in small spaces on-site are alleviated. The number of operatives on-site is reduced and wet trades may be eliminated. This method of construction is seen to be an advantage when skilled labour is scarce. The need to store many fixtures and fittings on-site, prior to installation is eliminated. Full-sized mock-ups can be produced in factories to enable testing and problem solving, which, on traditional construction sites can cause delays. Greater flexibility in design can be achieved through the use of modular construction if design and construction sequences are changed radically.

TABLE

2. FACTORS

TENDING

TO RETARD

THE USE OF PREFABRICATION

TECHNIQUES

l

Variations and traditional approaches to design limit the use of modular construction. o Modular construction requires time up-front for design and off-site manufacture. Units must be designed early and designs cannot be changed without causing considerable delays. o Space must be left for installation. If installation is delayed it may have adverse consequences for other work on site such as cladding and fitting out. l Installation problems in plugging in modules may deter their use. For example, tolerances may vary widely between those on-site and those in the factory and design faults may hinder installation. 0 Usually tt IS not possible to store modules on-site, so they must be craned into position at the time of delivery. This requires that manufacturers meet deadlines precisely and that just-in-time management is used. l Housing buyers tend to be conservative and resistant to modularized components unless final products are indistinguishable from those constructed traditionally on-site.

disadvantages of prefabrication outweigh the advantages. For example, many architects and specifiers do not fully understand what is required to use moduiar construction effectively. They often assume that units can be bought off-the-shelf, but fail to recognize that adaptations are required to permit installation into a particular building. Alterations may often be of such a magnitude that the units are better treated as bespoke and designed from scratch unless radical changes to other parts of the design are made at the outset. The use of prefabricated components also has implications for the sequence of construction and therefore may give rise to problems at the interface between trades. Detailed specification is essential if interface problems are to be avoided. An ability to negotiate and resolve problems quickly is needed-installation teams may have to work to tight cranage schedules in much the same way as curtain wall fixers. Furthermore, if these are not observed, damage may be caused to modules during installation. For example, on one Swedish housing site, a bathroom module had been inadvertently placed on top of pipe risers. The pipes had damaged the underside of the module and the floor inside the bathroom. The installation fitters were expected to have the skills necessary to make good the damage. Tables 1 and 2 summarize the advantages and disadvantages of prefabrication, drawing on the experience of prefabrication as applied to large office projects in the UK, and the experience of construction abroad, particularly in relation to housing.

FUTURES January~ebruary

1993

62

International

trends in construction

technologies

and the future

of housebuilding

The need for research R&D Evidence R&D

presented

in housing

spectrum

of those

components Housing

the firms

It would

evaluation

untried

attempts

Construction The

of choice

and untested

previous

firms.

to work

Firms

is made.

to

The

build,

and and

need

as designers on

rise

Users

rapidly

to those

housing

to and and

operation

and

before

consequences

similar

industrialized

the

materials

will be installed.

demand

be failures

building

tions

as those

changes

decade.

to change

which

may

has major

a

of using

experienced

in

techniques.

understand relationships and

well

may result

change

between

occur

and exter-

their

different

should

prepare industry

opportunities

may

which

Industry

in their

internal

firms

restructuring

to cope with.

in wasted

are incapable

to

industrial

housebuilders

for the organi-

each firm,

how

be ill equipped

may

implications

internally-within

pressures

which

firms

to new

representing

face up to the Failure

ways:

industry

both

need

competitive

traditional

techniques

just

to

across

Developers

to

be consulted

for

techniques

process,

in new

in different such

housing

construction

nally-between result

houses

technologies

of technology

solely

past.L7

technologies,

wait

may

what

should

implement

than

in the

approach

from

process reorganization

of the

structures

new

to

rather

case

about

how such

techniques

to rapidly

use of industrialized

zation

the

maintenance

be unwise

participants

production,

using

need to know

involve

been

decisions of

in building

maintenance. thorough

making

the need for a coordinated

should

in housing

implications

involved

suggests This

as has often

Associations

construction

article

involved

suppliers,

understand those

in this

construction.

their

the

organiza-

members

over

the

to

coming

and the adoption

of

of using.

Training Perhaps skills.

the most

pressing

Construction

flexibility 1980s

across

41%

of construction

1980s

there

appears from

grammes

in different

were work

during

the

carried

the

1980s’

demand

for

skilled

types

concentrated

was

North--into

is to modernize

of highly

boom, skilled

indicating workers.

East.

a failure

Two

the

mid-

of construction

South

Skill to

aspects

provide the

East of the UK:

During

migration

booming

to

Throughout

South

there.

the industry’s

operatives

of work.

in the

out

to have been a substantial

the

to meet

housebuilding

a supply

of tasks

workloads

1989,

experienced

on

a multitude

construction

particularly

need within

depends

labour-

shortages

plan

in

and late

training

of the problem

were prowere

evident: l

too few skilled

workers

were trained

and given sufficient

incentives

to stay in the

industry. l

skill to

needs carry

provide Construction in

the

changed out

the

evidence

and many

tasks

of carelessness

employment

economy

as

of those

required.

fluctuates

a whole.

But

in the industry

Building

defects

and inadequate more

or less

employment

were

and

no longer

construction

equipped accidents

skills. in accordance in

particular

with

fluctuations

occupations

FUTURES January/February

also

1993

j~ternatjonal

trends in construction

technologies

and the future

of ~o~sebuild~~~

63

fluctuates with the changing composition of construction output. Between 1974 and 1988, a decline in employment in construction has been accompanied by a shift in sectoral composition and occupational structure. The major growth sector in the mid-1980s was office construction of which a high proportion was based on prefabrication. For example, the widespread use of curtain walling eliminated the need for brickwork on many large projects and this reduced the demand for bricklayers and increased the demand for cladding fixers. Traditional housing construction methods are intensive in the use of skilled site labour such as bricklayers and plasterers, but employment of bricklayers fell by more than 30% and plasterers by nearly 25% in the period of 1974 to 1988.28 Any major attempt to expand new housing construction based mainly on traditional construction methods could therefore be liable to be severely constrained by shortages of craft skills, in particular of wet trades such as bricklaying and plastering. One of the principal attractions of industrialized housebuilding is that its use may reduce the need for scarce skilled site labour by combining factory production of components and sub-assembiies with less skilled assembly workers on-site. But workers assembling prefabricated housing need some training, including technical knowledge even if the need for traditional manual skills and intuition is less.2y Failure to ensure that appropriately skilled labour is available could lead to catastrophic failures as it has in the past. Housing will need to be ‘engineered’ to a greater extent in future if it is to be able to meet stringent energy and environ~lental requirements. The Chief Executive of Barratts has been quoted as stating that it would take IO years for UK housing to reach current Swedish standards in these respects because it would take that long to train the workforce to the requisite standards. Conclusions Major changes in technology require huge investments and it is important that the correct choices are made. In the short term, it may be sensible to use up existing stocks of materials. For example, it has been estimated that sufficient bricks are available in stockpiles now to build 170 000 houses.3” But if the attempt were to be made to expand housing production using only traditional methods, the rate of construction would be tightly constrained by shortages of skilled workers. The continuing decline in the number of people receiving construction training needs to be remedied. At the same time a new approach to housing construction technologies should be found to provide a ‘middle way‘ between out-of-date traditional techniques and fully industrialized production which is unlikely to be viable. R&D, new training programmes and changes to the organization of production must be implemented to ensure that problems experienced in previous use of industrailized construction do not recur in the future. It is likely that housebuilding to meet social needs will expand in the next few years. Because of the need for energy saving and shortages of traditional wet trade construction skills, the use of industrialized methods could grow. Undoubtedly, pressure for energy conservation will increase and Green Audits will spread and new technologies offer greater scope than traditional methods for meeting such requirements economically. But in the absence of major organizational changes, the use of new technology may not result in cost savings. Indeed, reviewing the history of the 196Os, Finnimore concluded that the system building oithe time was generally less productive than traditional methods.‘l

FUTURES ~anuary/February

1993

64

International

trend.< ,n construction

technologies

and the future

of hou.sebt~iiding

Investment now by government, industry organizations and by firms in the sectors likely to be involved in large scale provision of housing has a high probability of pay-off. Failure to make such investments is liable to result in increasing import penetration of prefabricated components, as was experienced in the office construction boom of the 1980s.-~L Strategic decisions need to be taken soon about which prefabrication techniques are likely to be most suitable and about their implications for the organization of construction processes and for the need for new training programmes. Office construction draws upon an almost entirely different set of resources of components, techniques and skills from traditional house production-the industries are in many ways quite separate. Further research is needed to assess the possibilities of transferring the knowledge gained in industrialized construction of offices, and the potential for adapting it to meet the needs of future housing construction.

Notes and references

1. National 2. 3. 3. 5. 6.

7. 8. 9. IO.

11. 12. 13. I-1.

IS. 16.

17. 18. 19. 20.

Economic Development Office, Strategy for Constn~tic~n R&D il.ondon. NEDO, 19841, pages 6 and 7, Illustrate a wide range of changes between houses buiit in 1935 and 1985. J. Barlow and A. King, ‘The state, the market and competitlvr strategy: the i~ou~ehuildin~ industry in Britain, France> and Sweden’, ~~~/;r~~~)rne/?~ and ~~~?~~/~~ fortt~corniti~. tnquky i1~0 Britkh Housslng The Report (London, National Federation of Housing Associations, 1985). Joseph Rowntree Foundation, Inquiry into Britkh Housing, Second Kcport (I ondon, Joseph Rowntree Foundation, 19911. C. Bramley, ‘Meeting houslng needs’ (Bristol, SAUS, University of Bristol, 19B91. Cg, see M. Kleinman. ‘A decade of change,: providing so<-ial housing 198s 1990’, mlmeo report to Joseph Rowntree Foundation, 1991; S. Wilcox, The Need for !?ocin/ Rented Ho~~ong in EngLrnd ~7 the 7990.5 (London, Institute of Housing, 1991). Centre for Strategic Studies in Construction, l/K Construe tinn Prorspects 2Utll (Reading, University of Reading, CSSC, 1990). Bullding Research Establishment, 5R~EA~~~New Home.s, Ver.sion 397: An E~?~,;r~~~~)ent~l Asscxsment for New Homes (BRE, 1991). 6. Finnimore, /-/ous~.5 for the Fuiure (London, Rivers Oram Press, 1989). M. Bowley, The British Building Industry: Four Studies in Response and Resistance to Change (Cambridge, Cambridge University Press, 1966) page 77; R. McCutchron, ‘Technical change and (41, 1975, pages 262-289; R. 6. White, social need: the case of high-rise flats’, Rese‘Trch Poky, Prefahrkation: A H&tory of Its Development in Great Britain (London, HMSO, 19651. S. Merrett, Sfate Hou.Gng in Britain (London, Routledge and Kegan Paul, 19791, page 89. B. Russell, &ti/&ng Systems, /~d~/strralisatiun and Architecture it ondon, Wiley. 19811, pages 44(i455. Merrett, op cif, reference 11, pages 130-I il A. Cullen, ‘Spcxculative housebuilding in Britain: some notes on the switch to timber frame production methods’, The Production of the Built Environment, ? (London, Bartlett School of Architecture, 1981). M. Ball, Housing Policy and Fconomlc Power: The Political Economy of Owner Occupation (London, Mrthuen. 1983), pages 185-188. It 1s not strictly accurate to descnhe brick.‘biock housing construction in the 1JK as ‘tradltional’. While the skills required in construction have changed little, new materials in the form of lightweight blocks are used extensively. It is as yet unclear whether any long-term problems may occur due to the Lltllization of these materiais. ‘0’ Farrell timher frame housing’, Construction News Magazine, March 1982. D. M. Gann, ‘The political economy of timber framed house production’ (Brighton, SPKC!, University of Sussex, 19841, page 27. ‘Timber frame houses “potential disaster”‘, r/-theGuardian, 31 April 1985. National House-Building Council, 4 Review of the Evidence about Timber Frame Dwe//ing.s (London, NHBC, 198 1); Association of Metropolitan Authorities, Timber Frame Housing-A Caution,lry Note (AMA, September 19831.

FUTURES

January/February

1993

lnter~ational

21. 22.

23. 24. 25.

26. 27. 28. 29.

30. 31. 32.

trends in construction

technologies

and the future

of ho~seb~iidjng

65

D. M. Gann, ‘High technology buildings and the Information Economy’, Habitat International, 74 (213, 1991. D. M. Cann, Technology Change and Construction Skills in the 7990s KIT8 RR05, ‘199%. European Conference on Integrated Home Applications, Amsterdam, 13-15 January 1991. D. M. Gann, ‘High technology buildings and the Information Economy’, Habitat international 14 (2!3), 1990. There are special reasons for this, for example there is a shortage of land rn Japan and much of the old stock IS very small and inadequate. It is often only possible to build on existing sites and frequent rebuilding is undertaken, for example to house a family as it expands. The need for frequent rebuilding encourages the use of prefabrication in an economy where construction labour is scarce. The average life of a Tokyo house is 18 years. Large Japanese housebuilders have their own schools to train erection teams and subcontractors who must pass a test before they can work on site. IPRA, Construction R&D, report prepared for the Construction Policy Directorate, Department of the Environment (Brighton, Innovation Policy Research Associates, 1992). D. M. Cann, Future SkillNeeds of the Construction lndlfstry (Brighton,Innovation Policy Research Associates, 79911. Moreover, much of the UK’s housing stock is ageing and will need extensive maintenance and improvement during the 1990s. This will increase the demand for multiskilled maintenance operatives. This stock also represents a considerable investment in embodied energy which should be calculated in any ‘green’ assessment of housing production. The Guardian, 25 January 1992. Finnimore, op tit, reference 9, page 238. In the case of curtain-walling for office buildings, components were imported and workers from overseas with the specialist skills necessary to assemble and install them were employed.

FUTURES J~nuary~ebr~a~

1993