1. Case study analysis of the material selection process during dwelling design in Flanders
Goodmorning everyone,
Today I will present a part of my PhD research to you, entitled “case….
Elke MEEX, Elke KNAPEN, Griet VERBEECK
Faculty of Architecture and Arts, Hasselt University, Belgium,

2. INTRODUCTION
Project sustainability level depends on early design decisions
Architect = important actor
Main focus = energy, environmental impact is gaining importance
Decisions based on intuition and experience
Move towards more sustainable material choices:
shortcuts and rules of thumb are insufficient
Goal of PhD = to develop a design-supportive methodology for architects for the assessment and integration of materials with low environmental impact, from the early design phase on
Need for knowledge on architects’ current approach for material selection

3. METHODOLOGY
Retrospective case study analysis (14 newly built dwellings)
Process mapping of design documentation:
When, at what moment of the design process?
To what level of detail?
Semi-structured interviews with the 9 architects
Who decides?
Why, on what basis?
 Small sample size, not representative, but useful insights

4. METHODOLOGY
Retrospective case study analysis (14 newly built dwellings)
Process mapping of design documentation:
When, at what moment of the design process?
To what level of detail?
Semi-structured interviews with the 9 architects
Who decides?
Why, on what basis?
 Small sample size, not representative, but useful insights
Separate research paper
Focus of today’s presentation

5. METHODOLOGY Design documentation =
Structured into 4 most prevalent design phases in Flanders:
Subdivided into six building layers:
Building structure (load bearing function)
Building skin (visible, exterior)
Building shell (mostly insulation)
Building systems (technical equipment)
Interior space (finishing materials)
Room separations (interior walls)
Figure based on: Brand, S., How buildings learn: What happens after they're built. 1994, New York: Penguin Group.

6. METHODOLOGY Design documentation =
Degree of specification of material decisions:
Material category (= concrete, wood, …)
Product type (= generic product with technical specifications, characteristics, performance levels, …)
Brand or producer (= specific product)
1) MATERIAL CATEGORY
2) PRODUCT TYPE
3) SPECIFIC PRODUCT/BRAND

7. METHODOLOGY Semi-structured interviews
Conducted in October – November 2015
Scheme completed during interviews: WHO (actors) and WHY (drivers)

8. STRUCTURE & SEPARATIONS
RESULTS
Building structure (load bearing function) & room separations (interior walls):
Early design = construction type by architect (experience) and client (preference, perception)
Detailed design = product by architect, client and structural engineer (in some cases)
Execution = brand/producer by contractor and structural engineer, focus on physical aspects
Construction type = interplay between architect (experience) and client (preference, perception)
SE: considers load bearing capacity and physical aspects
CO: considers mostly quality, constructability and rate of return
STRUCTURE & SEPARATIONS
Time Money
Ethical responsibility
Influence other parties
Legend MOTIVES:
Physical characteristics
Appearance
Subjective
Context
Culture
Legend ACTORS:
CL = client
AR = architect
P = producer / installer
EN = energy reporter
LG = local government
SE = structural engineer
CO = contractor

9. RESULTS Building skin (visible, exterior):
Early design = first preference of client (subjective, aesthetic), architect looks at context
Prior to permit submission = product specification in cost estimate by architect and client
Execution = brand / producer specification, within budget restrictions client
Product level in cost estimate (subject to change due to client’s budget restrictions)
SKIN
Time Money
Ethical responsibility
Influence other parties
Legend MOTIVES:
Physical characteristics
Appearance
Subjective
Context
Culture
Legend ACTORS:
CL = client
AR = architect
P = producer / installer
EN = energy reporter
LG = local government
SE = structural engineer
CO = contractor

10. RESULTS Building shell (mostly insulation):
Early design = based on energy target client, architect uses rules of thumb (conventional)
Detailed design / tendering = specified more by architect or energy reporter (performance level)
Execution = brand specification by contractor, within prescribed performance levels
Mostly “traditional” materials, except when clients or some architects have an “ecological” motivation (rare)
SHELL
Time Money
Ethical responsibility
Influence other parties
Legend MOTIVES:
Physical characteristics
Appearance
Subjective
Context
Culture
Legend ACTORS:
CL = client
AR = architect
P = producer / installer
EN = energy reporter
LG = local government
SE = structural engineer
CO = contractor

11. RESULTS Building systems (technical equipment):
Architects lack knowledge, especially on new techniques (heat pump, solar boiler, …)
Detailed design = “standard package” of systems proposed by architect, client usually agrees
Execution = based on technical knowledge of contractors and installers, within budget client
Specification, final choice = Budget is restrictions: sometimes basic systems are installed, replaced by more advanced ones later on
SYSTEMS
Time Money
Ethical responsibility
Influence other parties
Legend MOTIVES:
Physical characteristics
Appearance
Subjective
Context
Culture
Legend ACTORS:
CL = client
AR = architect
P = producer / installer
EN = energy reporter
LG = local government
SE = structural engineer
CO = contractor

12. RESULTS Interior space (finishing materials):
Walls, ceilings: conventional, some architects/clients prefer more ecological/healthy materials
Floors: material (and thickness) is assumed by architect during design
 final specification by client, advise from architect and producers
Budget restrictions: sometimes structure of ceilings and walls in secondary rooms remains unfinished
Budget restrictions: first an alternative flooring material, replaced by the final material later on
SPACE
Time Money
Ethical responsibility
Influence other parties
Legend MOTIVES:
Physical characteristics
Appearance
Subjective
Context
Culture
Legend ACTORS:
CL = client
AR = architect
P = producer / installer
EN = energy reporter
LG = local government
SE = structural engineer
CO = contractor

13. DISCUSSION Who decides which materials to use during building design?
Prior to building permit submission:
Mainly architect and client
Sometimes specialists are involved
After building permit submission:
Specialists (contractor, producers, …) are actively involved
Architect:
Is not always final decision maker
(= client, in control of budget) 
providing advise to the client

14. DISCUSSION Why, on what basis are material-related decisions made?
Budget constraints are present in all kinds of decisions
Skin and space (=visible): aesthetics and subjective reasons (taste)
Structure, separations, shell and systems (=invisible): physical characteristics, some subjective reasons (perceptions, believes, … )
Ethical drivers: may be due to the context of the interview
Remark: in large-scale survey (February 2014) it was found that cost (79%), wishes client (75%), previous experience (73%), personal knowledge (68%) and aesthetics (68%) were the most common drivers in material selection.
“Sustainable” drivers were only selected by 10-15% of the architects.

15. CONCLUSIONS
Architects are set in their habits of decision making  need for:
More awareness, commitment of architect
Reliable information and support on sustainable material selection
Knowledge is used in further development of PhD research
Further research will be done within PhD:
Appropriate default values and assumptions for early design assessment
Ways to provide usable and design supportive feedback
Desires regarding the tool format …

16. Thank you for your attention !
Questions ?
Research funded by a PhD grant from VLAIO
PhD Candidate: Elke Meex
Supervisor: Prof. dr. ir. Griet Verbeeck
Co-supervisor: dr. Ir. Elke Knapen
Faculty of Architecture and Arts – Research Group ArcK – Hasselt University