What is Material Properties and Selection?
Material properties and selection is the process of matching a building material's physical characteristics — strength, density, durability, cost, and appearance — to the demands of a specific design. Architects compare materials like steel, timber, and concrete against these properties before choosing one.
Material properties and selection means evaluating a material's mechanical, physical, and aesthetic properties — such as strength, density, durability, and cost — to choose the best fit for a building's structural and design needs.
- •High strength-to-weight ratio
- •Long, column-free spans
- •Non-combustible but loses strength when hot
- •Higher embodied carbon per kg
- •Recyclable at end of life
- •Lower density, moderate strength
- •Renewable, stores carbon while growing
- •Combustible, needs char-layer design
- •Lower embodied carbon than steel
- •Faster, quieter on-site erection
Try it: interactive calculator
Step-by-step worked examples
Structural steel has a yield strength of about 350 MPa and a density of 7.85 g/cm³. Find its specific strength.
Specific strength = σ / ρ = 350 / 7.85 = 44.6 MPa·cm³/g
A grade of structural timber has a strength of 40 MPa and a density of 0.5 g/cm³. Compare its specific strength to the steel above.
Specific strength = 40 / 0.5 = 80 MPa·cm³/g 80 > 44.6, so this timber is stronger per unit weight than the steel example
Aluminum alloy used in facade framing has a yield strength of 270 MPa and density 2.7 g/cm³. Find its specific strength.
Specific strength = 270 / 2.7 = 100 MPa·cm³/g
Flashcards
Quick quiz
Q1.A material has a strength of 200 MPa and a density of 4 g/cm³. What is its specific strength?
Q2.Which property best measures how much a material weighs for a given strength?
Q3.Why might an architect choose timber over steel for a low-carbon project?
Q4.Two materials have the same strength, but Material A is denser than Material B. Which has the higher specific strength?
The full card deck, worked steps and AI-tutor support for “What is Material Properties and Selection?” are in Notek — study by hand before your exam.
Common mistakes
Choosing a material based on strength alone. — Correct: Strength must be weighed against density, durability, fire performance, cost, and embodied carbon together.
Assuming a stronger material is always the better choice. — Correct: A lighter, moderately strong material can outperform a heavier, stronger one once self-weight and cost are considered.
Ignoring durability and maintenance over the building's life. — Correct: A material's long-term performance — corrosion, weathering, upkeep — affects total lifecycle cost as much as initial strength.
Treating embodied carbon as irrelevant to material choice. — Correct: Embodied carbon is now a core selection criterion alongside strength and cost for sustainable design.
FAQ
What is material properties and selection?
It is the design process of comparing a material's strength, density, durability, cost, and appearance to choose the right fit for a building.
What is the material specific strength formula?
Specific strength = σ / ρ, where σ is tensile or yield strength and ρ is density — it measures strength relative to weight.
How do you calculate specific strength of a material?
Divide the material's strength (in MPa) by its density (in g/cm³) to get its strength-to-weight ratio.
What are examples of material properties and selection?
Comparing steel's high strength-to-weight ratio against timber's low embodied carbon, or choosing aluminum over steel for lightweight facade framing, are typical selection examples.