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Examination  of  Emerging  Construction  Technologies  and  Procurement  Forms  appropriate  for  use  in  Housing  Delivery  in  Nigeria    

Abimbola  Windapo1  and  Chucks  Omeife2    

1Senior   Lecturer,   Dept.   of   Construction   Economics   and   Management,   University   of   Cape   Town,   e-­‐mail:  Abimbola.windapo@uct.ac.za  2President,  Nigerian  Institute  of  Building      Abstract  

The   paper   examines   construction   technologies   and   procurement   forms   appropriate   for   use   in  housing   delivery.   A   strategic   literature   survey   is   used   in   identifying   emerging   construction  technologies   and   procurement   forms   used   in   housing   delivery.   The   survey   reveals   volumetric  construction,   panelized   timber/steel   frames   and   sustainable   system   building   as   some   of   the  modern  construction  technologies  used  in  housing  delivery  in  Nigeria  and  that  these  technologies  are   not   aligned   to   all   forms   of   procurement   because   they   comprise   of   elements   which   are  dependent  on  the  architectural  concept  and  design.  Based  on  these  findings,  the  paper  concludes  that  housing  provision  will  be  enhanced  with   the  use  of  modern   construction   technologies  and  integrated  project  procurement  methods.    Key   words:   Design,   Housing,   Integration,   Procurement,   Sustainable   Building   Systems   and  Technology    

INTRODUCTION  

Shelter,  like  food  and  clothing,  is  a  basic  human  need  with  profound  impact  on  life.  Therefore,  the  

search   for   shelter  has   spanned  over   the  years   and   from  all   indications,   appears   to  have  eluded  

complete   solution   in  modern   times,   for  most   individuals,   especially   in  a  developing   society   like  

Nigeria.   While   the   housing   needs   of   pre-­‐colonial   Nigeria   at   the   village   levels   were   met   by   a  

combination  of  the  prospective  home  owner’s  efforts  and  that  of  the  society  to  which  he  belonged  

his  more  modern  counterpart  in  the  urban  area  today  is  constantly  faced  with  the  problem  of  how  

and  where  to  put  up  a  shelter  of  his  own  (Ibagere,  2002).  

 Historically,   from  the  beginning  of  civilization,  attention  has  been  paid  on   the   form,  placement,  

and  provision  of  human  habitation.  Demand   for  urban  housing   increased  and   for  centuries   this  

demand   was   filled   by   unplanned   additions   to,   and   subdivisions   of,   existing   structures.   Where  

climate  permitted,  squatting  (occupying  without  title  or  payment  of  rent)  became  commonplace,  

but  provided  only  temporary  shelter.  Overcrowding  in  the  cities  has  caused  slums  to  spread  and  

shantytown   suburbs   to   emerge   in   most   of   the   larger   urban   centres   in   Nigeria   (Encyclopedia  

Britannica,  2008).  In  the  postindustrial  society  of  the  20th  century,  housing  in  developing  nations  

and  poor  parts  of  developed  countries  continues  to  be  of   insufficient  quality  and  does  not  meet  

the   demand   of   some   parts   of   the   population.   Vacant,   abandoned   central-­‐city   housing   exists  

alongside   structures   that   are   usable   but   overcrowded   and   buildings   that   are   structurally  

reclaimable  but  are  functionally  obsolete  (Encarta  2007).  

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Housing   is   a   big  problem   confronting  many  Nations   of   the  world   and  particularly   for   the  Low-­‐

income  earner  in  Nigeria.  Akeju  (2007)  stated  that  since  Independence  in  1960,  all  Governments  

of   Nigeria   have   highlighted   housing   as   a   major   priority.   Nigeria   has   witnessed   rapid   rate   of  

urbanization  in  the  last  two  decades  and  it  is  estimated  that  over  40%  of  the  Nigerian  population  

now   live   in   urban   areas.   The   rapid   rate   of   urbanization   has   brought   with   it   some   significant  

problems   including   shortage   of   housing,   overcrowding,   traffic   congestion,   environmental  

degradation,  inadequate  infrastructure  and  services,  etc.  Various  experts  such  as  Adetona  (2007),  

Akomolede   (2007),   Ajanlekoko   (2007),   Akewusola   (2007),   Ajayi   (2007),   George   (2007)   and  

Olawore   (2007)  have   also   observed  how  enormous   the  housing  problems   are.   These  problems  

were  identified  as  the  high  cost  of  the  provision  of  infrastructure,  unaffordable  housing,  lack  of  a  

workable  housing  policy  and  unplanned  urban  centres.  According  to  Mordi  (2002),  about  70%  of  

Nigerians  are  either  homeless  or   live   in   shanties  and  batchers,  businesses  and  organizations   in  

the   building   industry   have   stagnated,  Nigerians  who   live   in   or   pass   through   the   slums,   ghettos  

and   shanties   are   victims   of   crimes   and   violence   associated   with   the   negative   culture   in   these  

areas  and  the  whole  Nigerian  economy  is  adversely  impacted.    

 

However,   being   the   third  most   important   thing   to  man   after   food   and   clothing,   provision   of   a  

decent  accommodation  or  shelter  is  a  necessity  that  needs  to  be  fulfilled  at  affordable  rates.  It  is  

the  aim  of  this  paper  therefore,  to  examine  the  emerging  technologies  that  are  appropriate  for  use  

in  housing  delivery  in  Nigeria.    

 

Definition  of  Low  Cost  Housing    

Lefebvre   (2004)   defines   low-­‐cost   housing   to   be   affordable   housing   for   poor   or   low-­‐income  

individuals  and  families  which  would  include  not  only  individual  houses  but  also  rental  housing.  

This  definition  would   include  a  wider   range  of  housing   types   in   terms  of   their   costs   relative   to  

lower  income  segments  of  the  population  of  different  areas  and  countries  i.e.  housing  that  lower  

income  families  can  afford  to  build  themselves  or  participate  in  their  construction  as  some  form  

of  equity  or  acquire  through  some  form  of  aid  as   in  housing  cooperatives  or  afford  to  rent  with  

their  income.  It  should  have  basic  utilities  such  as  electricity,  water,  sanitation  and  should  be  built  

with  strong  and  durable  materials  so  that  they  can  last  (with  a  minimum  of  maintenance)  at  least  

20  to  25  years  or  a  period  corresponding  to  the  term  of  loans  and  mortgages.    

 

REVIEW  OF  EMERGING  CONSTRUCTION  TECHNOLOGIES  USED  IN  HOUSING  

Modern  methods  of  construction  is  a  collective  term  being  used  to  describe  a  number  of  new  and  

emerging   construction   technologies   that   are   being   introduced   into   house   building   that   differ  

significantly   from   so-­‐called   ‘traditional’   brick   and   block   construction.   There   is   no   precise   or  

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universally  agreed  definition  of  what  constitutes  modern  methods,  although  in  2003  the  Housing  

Corporation  of  the  U.K  introduced  a  six-­‐fold  classification  system  for  describing  the  construction  

methodologies   for   current   house   building.   The   sixth   category   describes   all   traditionally   built  

dwellings;  hence  categories  1  to  5  would  be  classed  as  modern  methods  of  construction.  Each  of  

the   construction   classes   can   be   built   using   a   number   of   different  materials,   leading   to   a  wider  

range  of  more  specific  descriptions,  such  as  ‘volumetric  steel  frame  construction’,  ‘timber  framed  

panelized  construction’  and  so  on.  The  most  common  materials  are  timber,  steel  (in  the  form  of  

light-­‐gauge   galvanized   steel)   and   concrete,   although   ranges   of   composite   systems   are   being  

introduced  also  (CE139,  2005).  

   Main  Forms  of  Emerging  Construction  Technologies    The  main  forms  of  emerging  construction  technologies  used  in  housing  are  as  follows:  

 Volumetric  construction  

 Three-­‐dimensional   units   manufactured   within   a   factory.   Units   can   be   made   from   a   range   of  

materials   (any  material   that   can   produce   a   structural   panel   could   be   used   to  make   volumetric  

units)  but  most  commonly  are  framed  structures  in  timber  or  light  gauge  steel.  See  Fig  A.1.  

 

Panelized  timber  frame  

Arrangement   of   studs   and   rails   enclosed   within   two   sheets   of   lining   material   with   insulation  

within.  The  stud  can  either  be  of  solid  construction  (depth  usually  at  least  89mm)  or  of  timber  I  

beams   (depths   usually   150mm   or   above).   There   is   some   debate   within   the   industry   about  

whether   or   not   timber   frame   should   be   regarded   as   a   modern   method   of   construction.   The  

amount  of  fabrication  done  in  the  factory  varies  but  for  timber  frame  to  be  regarded  as  a  ‘modern  

method’  a  manufacturer  would  need  to  do  substantially  more  than  supply  panels   that  comprise  

the   studwork   and   sheathing   board,   or   incorporate   some   recent   innovation   such   as   the   use   of  

timber  I  beams.  Factory  installation  of  insulation  should  produce  good  quality  control.  Panelized  

construction  also  tends  to  lead  to  more  airtight  structures  provided  they  are  made  accurately.  See  

Fig  A.2.    

Panelized  steel  frame  

Panels  of   light  gauge  steel  are  usually  delivered  without   insulation  or  sheet  materials  (although  

they   can   have   insulation   factory   applied).   Typically   the   depth   of   studs   would   be   ~70mm   or  

greater.  See  Fig  A.3.  

 

   

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Structural  insulated  panels  (SIPs)  

SIP  panels   are   a   composite   of   two   sheets   of   lining  material   (typically   oriented   strand  board   or  

cement  based  boards)  bonded  to  a  continuous  rigid  foam  core  to  produce  a  structural  panel.  The  

panels   need   not   contain   internal   load-­‐bearing   studs,   although   studs   are   sometimes   included  

around  openings  and  at  corners.  SIP  systems  sometimes  also  use  the  same  specification  of  panel  

for  roof  structures.  See  Fig  A.4.  

 

Composite  panels  

 A   number   of   composite   panels   are   currently   in   use,   which   comprises   a   rigid   insulation   core  

within  a  wire  space  frame,  all  enclosed  within  a  fine  aggregate  concrete  or  render.  Openings  for  

windows  etc.  can  be  formed  in  the  factory  or  formed  on  site  by  using  a  range  of  different  panels  

(e.g.  special  lintel  and  spandrel  panels).  See  Fig  A.5.  

 

Tunnel  form  construction  

Tunnel   form   is   a   technique   to   produce   internal   walls   and   floors   using   cast   in-­‐situ   concrete.  

External  walls  (apart  from  the  side  walls)  are  constructed  using  other  techniques,  which  can  be  

conventional  cavity  masonry,  or   framed   infill  panels.  Construction  detailing  would  be  similar   to  

cross  wall  and  concrete  frame  constructions.  The  walls  would  be  cast  onto  prepared  foundations  

comprising  typically  a  beam  and  block  ground  floor.  See  Fig  A.6.  

 

Sustainable  System  Building  

The   sustainable   system  building   shown   in   Fig  A.6,   developed  by  Prof.   Olusanya   combines   both  

architecture  and  building  technology.  It  utilizes  a  simple  structural  system  of  modular  composite  

floor  on  parallel   load-­‐bearing  walls   to  create  a  surprising  variety  of  optimally   functional  spaces  

with   emphasis   on   natural   light   and   cross-­‐ventilation   for   environmental   comfort   as   well   as  

effective  energy  management.  

 

Insulating  formwork  

Insulating   formwork   uses   two   layers   of   rigid   foam   as   permanent   shuttering   for   a   reinforced  

concrete  wall.  The  insulation  can  be  in  the  form  of  two  sheets  of  rigid  foam  tied  together,  or  in  the  

form  of  large  hollow  blocks.  

 

Aircrete  block  and  plank  

 Aircrete  has  been  in  use  for  many  years  in  block  work,  but  a  recent  innovation  is  the  use  of  thin  

joint   techniques,   where   a   thin   (4mm)   layer   of   special   adhesive   replaces   the   normal   relatively  

thick  mortar   joint.  Large  planks  of  reinforced  aircrete  can  also  be  used  to  produce  both  ground  

and  intermediate  floors,  and  also  to  create  a  pitched  roof  structure.  

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Prospects  for  the  use  of  Emerging  Contruction  Technologies  in  Nigeria  

 

Appropriateness  for  Use  in  Nigeria  

There  is  an  ever  increasing  growth  in  the  Population  of  Nigeria  particularly  in  Major  States  with  

Lagos  State  have  a  figure  of  9,013,534  after  Kano  with  a  figure  of  9,383,682  according  to  the  2006  

National   Census   figure   (National   Population   Commission,   online).   Going   by   the   Vision   of   the  

Lagos  State  government  on  the  Mega  City  Project  christened  “New  City  on  the  Atlantic”  (African  

loft,  2007)  and  the  Federal  Governments  expectation  with  the  “  Vision  20:  2020,  MMC  is  the  ready  

solution  to  the  problems  of  housing  in  Nigeria.  

 

Benefits  of  the  use  of  Emerging  Construction  Technologies  in  Housing  Delivery  

Emerging  construction  technologies  have  the  following  advantages  in  that  it  is  a  faster  method  of  

Construction  it  can  halve  on-­‐site  construction  duration;  require  less  on-­‐site  labour;  large  number  

of   units   can   be   constructed   ;   the   faster   construction   and   reduced   on-­‐site  work   brings   financial  

benefits  to  developer  in  terms  of  shorter  period  of  financing  project  and  also,  buildings  provided  

are   up   for   sale   faster.  However,   these   construction   technologies   are   not   aligned   to   all   forms   of  

procurement   because   they   have   components   which   combine   both   architecture   and   building  

technology  (Olusanya,  2011).  

 

OVERVIEW  OF  PROJECT  PROCUREMENT  TYPES    

According  to  Love  et  al.  (1998),  the  terms  ‘procurement  systems’  and  ‘contractual  arrangements’  

are   usually   used   synonymously.   Love   et   al.   (1998)   defined   a   procurement   system   as   an  

organizational   system   that   assigns   specific   responsibilities   and   authorities   to   people   and  

organizations  and  defines  relationships  of   the  various  elements   in   the  construction  of  a  project.  

Harris  and  McCaffer  (2001)  noted  that  the  client  or  adviser/project   leader  according  to  need  or  

preference   would   select   the   type   of   contract.   Established   methods   of   project   procurement  

identified  by  Masterman  (1992)  and  cited  by  Harris  and  McCaffer  (2001),  which  determines  the  

contractual  relationship  between  the  client  and  other  parties  at  the  design  and  construction  stage  

can  be  categorized  as:  -­‐    

• Traditional  (separated  and  cooperative)  method  

• Design  and  Build  (integrated  and  holistic)  method  

• Management  (management-­‐oriented)  method  

• Discretionary  

These  methods   are   further   sub-­‐classified   into   the  methods   shown   in   Figure   1.   Osanmi   (1999)  

characterizes   the   traditional   procurement   method   by   a   clear   separation   of   design   and  

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construction   process.   Harris   and   McCaffer   (2001)   notes   that   traditionally,   clients   have   often  

preferred  to  engage  someone  able  to  interpret  their  needs  into  a  clear  design  before  proceeding  

with   the   construction   phase.   An   architectural   firm,   engineering   firm   or   consortium   acting   as  

consultants  is  responsible  for  design,  while  a  general  contractor  handles  the  construction  phase  

after   entering   into   a   construction   contract   with   the   client   through   competitive   bidding   or  

negotiation.  According  to  Love  (2002),  an  architect  is  typically  the  first  point  of  contact  for  clients  

and,   because   their   advice   is   heavily   relied   upon,   it   is   often   in   the   interest   of   the   architect   to  

persuade  the  client  to  use  a  traditional  method,  as  they  can  take  a  lead  role  in  the  project  as  well  

as   maximize   his/her   fees.   The   traditional   method   of   project   procurement   is   a   widely   used  

procurement  method  in  Nigeria  (Osanmi,  1999).  

 

   

 

 

 

 

 

 

 

 

Figure  1:  Classification  of  Project  Procurement  Methods    

Sources:  Adapted  from  Love  et  al.  (1998);  Osanmi  (1999)  and  Alhazmi  and  McCaffer  (2000)    

 Osanmi   (1999)   explains   design   and   build   or   design   and   construct   as   a   procurement   method  

where  the  contractor  provides  the  design  and  construction  under  one  contract  as  different  from  

the  traditional  system  where  design  is  separate  from  construction.  Molenaar  and  Songer  (1998)  

noted  that  design  and  build  has  steadily  become  a  procurement  method  of  choice  for  many  public  

sector  agencies  in  the  United  States.  Osanmi  (1999)  cites  that  all  design  and  build  contracts  have  

two  principal  characteristics:  -­‐  

1. The   contractor   is   responsible   for   both   the   design   and   construction   and   employs   the  

services  of  other  relevant  professionals  (architects,  engineers  etc.)  that  may  be  required,  

with   the   client  having   a  professional   agent  who  advises  him.  Contrary   to   this   assertion,  

Bowen   et   al.   (1999)   found   that   clients   are   generally   offered   advice   on   only   a   limited  

selection  of  procurement  systems.  

2. The  contract  between   the  client  and  contractor  has  a   final  and   inclusive  price   that  does  

not  vary  unless  the  client  requires  changes  to  be  made.  

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Love  et   al.   (2000)   stated   that  Project  management   is  not   considered  as   a  procurement  method  

because  it  could  be  applied  to  any  procurement  method,  and  that  the  term  merely  means  that  the  

client  has  employed  an  agent  to  assist  in  undertaking  a  supervisory  and  coordination  role  within  

the   project.   The   construction   management   procurement   method   differs   from   Project  

Management   in   that   there   are   several   trade   contractors   involved   in   this   procurement   process.  

The  characteristics  of  the  construction  management  procurement  method  are  as  follows:  -­‐    

• There  is  no  single  main  contractor;  

• The  client  enters  into  several  trade  contracts  for  work  package  comprising  portions  of  the  

project;  

• A  construction  manager  runs  the  project.  

 

The   labour-­‐only   form   of   procurement,   which   is   popular   in   Nigeria,   involves   the   client   in   the  

purchase  of  materials  while  leaving  construction  to  a  labour-­‐only  contractor  who  gets  paid  for  the  

cost  of  engaging  labour  and  for  his/her  overheads  and  profits.  An  agreement  is  normally  reached  

upon  who  hires  plants  for  the  works,  be  it  the  client  or  the  contractor.    

   

CONCLUSION  

Based   on   the   findings   of   the   literature   survey,   it   can   be   concluded   that   there   are   emerging  

construction  technologies  that  can  be  used  in  the  provision  of  low  cost  housing  in  Nigeria  and  that  

the  integrated  form  of  procurement  will  be  used  with  these  technologies.  Following  that,  the  use  

of  emerging  construction  technologies  in  the  housing  delivery  process  will  bring  about  the  use  of  

the   integrated   form   of   construction   procurement   process.   This   implies   that   the  

contractor/developer/architect  will   be   responsible   for   both   the   design   and   construction   of   the  

buildings.  Housing  no  doubt,  is  very  essential  and  it  is  currently  out  of  the  reach  of  a  vast  majority  

of   Nigerians   and   these   emerging   technologies   and   form   of   procurement  will   be   appropriate   in  

filling  this  housing  gap.  

 

RECOMMENDATIONS  

Based   on   the   conclusion   of   the   research   study,   the   following   recommendations   are   hereby  

proffered:  

1. Emerging construction technologies should be explored in low cost housing delivery in Nigeria

through concerted efforts by the government or and the private sector.

 

  8  

2. Government   and   private   sector   should   also   explore   the   integrated   form   of   project  

procurement  such  as  design  and  build  and  package  deal  contracts  when  initiating  housing  

delivery  programmes.  

   

References      Adetona,  D.  (2007).  “Housing  sector  in  2007;  Expectation  for  2008”.  Punch  Newspaper,  December        

31,  pp.  38    Ajanlekoko,   O   (2007).   “Housing   sector   in   2007;   Expectation   for   2008”.   Punch   Newspaper,  

December    31,  pp.  38    Ajayi,  O  (2007)..  “Housing  sector  in  2007;  Expectation  for  2008”.  Punch  Newspaper,  December  31,  

pp.  38    Akeju  A.A  (2007)  “Challenges  to  providing  affordable  housing  in  Nigeria;  Paper  presented  at    

The   2nd   Emerging   Urban   Africa   International   Conference   on   Housing   finance   in   Nigeria,Abuja.  

October,  2007.  

 Akewusola,   W.   (2007).   “Housing   sector   in   2007;   Expectation   for   2008”.   Punch   Newspaper,  

December  31,  pp  38    Alhazmi,   T.,   and   McCaffer,   R.   (2000)   Project   Procurement   System   Selection   Model,   Journal   of  

Construction  Engineering  and  Management,  126,  3,  176-­‐184.    

 Akomolede,   K.   (2007).   “Housing   sector   in   2007;   Expectation   for   2008”.   Punch   Newspaper,  

December  31,  pp  38    Bowen,   P.   A.,   Pearl,   R.   G.,   and   Hindle,   R.   D.   (1997)   The   effectiveness   of   building   procurement  

systems   in   the   attainment   of   client   objectives.   In   C.I.B.   W-­‐92   Procurement   Conference  Proceedings,  Montreal,  May  1997.  

 CE139,  2005:  “Building  energy  efficient  buildings  using  modern  methods  of        construction”,  2005;  

London;  Energy  Saving  Trust;  bestpractice@est.org.uk  www.est.org.uk/housingbuildings    Encarta   2007,   “Housing   (shelter)”   -­‐   Encarta   2007,   Microsoft®   Encarta®   Online   Encyclopedia  

2007  <http://encarta.msn.com  ©  1997-­‐2007  Microsoft  Corporation.>  27  October,  2007  

Encyclopædia   Britannica   (2008).   “Nigeria”   Encyclopædia   Britannica   Online.   14  Apr  2008  <http://www.britannica.com/eb/article-­‐259752>.    

 George,   K.   (2007,   December   31).   “Housing   sector   in   2007;   Expectation   for   2008”.   Punch  

Newspaper,  pp  42        Harris,   F.,   and  McCaffer,   R.   (2001)  Modern  Construction  Management,   5th   Ed.,   Oxford:   Blackwell  

Publishing  Company.  

 

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Ibagere  O.  P.,  (2002),  ‘The  dividends  of  democracy-­‐  How  far  with  housing  for  all’:  Paper  Presented  at   the   Delta   state   governments   seminar   on   the   National   Housing   Fund.   <http:  //www.deltastate.gov.ng/retreat.htm.>  16  March,  2008  

 Lagos-­‐mega-­‐city-­‐project:   New-­‐city-­‐on-­‐the-­‐Atlantic   (2007,   September   18),   African   loft  

http://www.africanloft.com/lagos-­‐mega-­‐city-­‐project-­‐new-­‐city-­‐on-­‐the-­‐atlantic/    Lefebvre,  B  (2004).  ‘Affordable  Housing’:  http://arch.designcommunity.com/post-­‐8176.html  12    August,  2004  

Love,  P.  E.  D.,  Skitmore,  M.,  and  Earl,  G.  (1998)  Selecting  a  Suitable  Procurement  Method  for  a  Building  Project,  Construction  Management  and  Economics,  16,  221-­‐233.  

Masterman,  J.  W.E.  (1992)  An  Introduction  to  Building  Procurement  Systems,  London:  E&FN  Spon.    

Mordi  S.  E.,   (2002),   “Social  Policy  and  Housing  Need   in  Nigeria”.  A  Two  day  Workshop  on  Your  Right   to   own  a  House   (by  Delta   State  Ministry   of  Housing)   held   on  26  &  27   June  2002,  Asaba  <http://www.deltastate.gov.ng/retreat.htm>16  March,  2008.  

 National   Audit   Office   (2005):   ‘Using   modern   methods   of   construction   to   build   homes   more  

quickly  and  efficiently’  Report  by  the  National  Audit  Office;  November  2005,  Buckingham        National  Population  Commission  (Online)  List  of  Nigerian  states  by  population.  Retrieved  19:43,  

May  6,  2009,  from  http://population.gov.ng    NBRRI   (2008).   Excerpt   from   the   Nigerian   Building,   Road   and   research   Institute,   web   site   <  

http://www.nbrri.gov.ng/achievements.htm>,   <http://www.nbrri.gov.ng/index.htm>;  acessed,  March  23,  2008,  6:14:35  PM:    

 Olawore,  A.  (2007).  “Housing  sector  in  2007;  Expectation  for  2008”.  Punch  Newspaper,  December  

31,  pp  38      Olusanya,  O.   (2011)  Sustainable   System  Building   imperative   and  Mass  Housing  Production   in   a  

Developing  Economy    Osanmi,  D.  (1999)  Comparison  of  Procurement  Methods  based  on  Clients’  Performance  Criteria,  

Unpublished  Report,  University  of  Lagos.    

                                 

  10  

       Appendix  

               

Figure  A.1  Volumetric  unit  being  craned  into  place                                                                                              Figure  A.4  Image  showing  construction  of  SIP  panels    Source:  CE139,  2005                                                                                                                                                                                            (Source:  Kingspan  TEK,  2005)                              

                       Figure  A.2  Timber  fame  panel  showing  factory-­‐applied  window  and  insulation                              Figure  A.5  Composite  panel  systems  in  use  Source:  CE139,  2005                        Source:  CE139,  2005      

                                       Figure  A.3  Open’  light  gauge  steel  framed  panels  being  erected                                                  Figure  A.6  Skeletal  Tunnel  Form  Construction        

  11  

   Figure  A.7  Sustainable  System  Building