Material Selection

• Design life expectation (25, 50, 60, 100+ years)
• Resistance to moisture, freeze-thaw, UV, pollution, biological attack
• Maintenance frequency and cost
• Patina and aging character (graceful vs. degrading)
• EN 206 exposure classes (concrete); EN 350 durability classes (timber)
• Corrosion resistance (metals); efflorescence (masonry)

Criterion 3: Thermal Properties

• Thermal conductivity (λ, W/mK)
• Specific heat capacity (c, J/kgK)
• Thermal mass (decrement delay, admittance)
• Contribution to U-value calculation
• Thermal bridging potential (ψ-values at junctions)

Criterion 4: Acoustic Properties

• Sound absorption coefficient (α) and NRC
• Sound reduction index (Rw, dB)
• Impact sound insulation (Ln,w)
• Flanking transmission paths
• Resonant frequency (for panel absorbers)

Criterion 5: Fire Performance

• Euroclass rating (A1 to F) / ASTM E84 (Class A, B, C)
• Fire resistance period (REI 30 to REI 240)
• Reaction to fire (ignitability, flame spread, smoke production)
• Charring rate (timber: 0.65 mm/min softwood, 0.50 mm/min hardwood)
• Concrete cover requirements for fire rating
• Intumescent and board-based fire protection for steel

Criterion 6: Embodied Carbon and Sustainability

• Embodied carbon (kgCO2e per kg, per m², or per m³)
• LCA stages A1-A5, B1-B7, C1-C4, D
• Recyclability and recycled content
• Renewable/non-renewable resource base
• Transportation distance (local vs. imported)
• Circular economy potential (Design for Disassembly)

Criterion 7: Cost

• Material cost (per m², per m³, per linear meter)
• Installation labor cost
• Maintenance and replacement costs over design life
• Whole-life cost (initial + maintenance + replacement + end-of-life)
• Supply chain reliability and lead times

Criterion 8: Aesthetic Quality

• Color, texture, pattern, translucency
• Surface finish options
• Ageing character and patina
• Scale and module relationships
• Tectonic expression (honesty of material)
• Contextual appropriateness (regional materials, cultural associations)

1.2 Decision Matrix Template

Scoring: 1 (poor) to 5 (excellent) per criterion. Apply weighting multipliers (1.0-3.0) based on project priorities.

Interpretation: Highest weighted total = preferred option. Sensitivity analysis: vary weights ±0.5 to test robustness. If options score within 5%, treat as equivalent and decide on qualitative factors.

Section 2: Concrete

2.1 Types

In-Situ (Cast-in-Place):

• Poured into formwork on site; cures in position
• Maximum flexibility in form and geometry
• Grades: C20/25 (foundations), C30/37 (structural frames), C40/50 (high-rise columns), C50/60 (prestressed)
• Minimum 28-day strength; continued strength gain over months

Precast:

• Factory-produced elements (beams, columns, panels, stairs, floors)
• Superior quality control; consistent finish; rapid erection
• Hollow-core slabs: 150-500 mm deep, spans 6-16 m
• Sandwich panels: structural + insulation + facing leaf in single unit

Glass-Fibre Reinforced Concrete (GRC/GFRC):

• Thin (10-25 mm) concrete panels with alkali-resistant glass fibres
• Lightweight: 15-20 kg/m² (vs. 100+ kg/m² for solid precast)
• Cladding and facade applications; complex curved forms
• Flexural strength: 20-30 MPa (vs. 3-5 MPa for plain concrete)

Ultra-High Performance Concrete (UHPC):

• Compressive strength: 120-200 MPa (vs. 30-50 MPa standard)
• Steel fibre reinforced; no conventional rebar needed for thin sections
• Density: 2,400-2,600 kg/m³
• Enables extremely thin elements (25-75 mm structural walls, 15-30 mm panels)
• Self-healing micro-cracks; exceptional durability
• Cost: 5-10× standard concrete
• Exemplars: MUCEM Marseille (Ricciotti), Ductal bridges

Self-Compacting Concrete (SCC):

• Flows under its own weight; no vibration needed
• Superior finish quality; fills complex formwork without voids
• Used for architectural exposed concrete with demanding finish requirements

2.2 Finishes

2.3 Key Properties

• Density: 2,300-2,400 kg/m³ (normal weight); 1,400-1,800 kg/m³ (lightweight)
• Thermal conductivity: 1.0-1.8 W/mK (normal); 0.5-0.8 (lightweight)
• Specific heat capacity: 840-1,000 J/kgK
• Thermal admittance: 5.0-6.0 W/m²K (excellent thermal mass)
• Embodied carbon: 150-200 kgCO2e/m³ (standard OPC concrete); 80-120 kgCO2e/m³ (low-carbon with GGBS/PFA replacement)
• Fire rating: inherently non-combustible (Euroclass A1). Concrete cover for fire resistance: 25 mm (REI 60), 35 mm (REI 90), 40 mm (REI 120), 55 mm (REI 240)

2.4 Architects of Concrete

• Tadao Ando: Smooth board-marked finish with precise tie-hole patterns (600 mm grid); Church of the Light, Naoshima museums
• Peter Zumthor: Textured, layered concrete (Therme Vals — local quartzite aggregate; Bruder Klaus Chapel — charred timber interior formwork)
• Louis Kahn: Monumental concrete with expressed structure (Salk Institute, National Assembly Dhaka — concrete + marble aggregate)
• Oscar Niemeyer: Sculptural white concrete (Brasilia Cathedral — hyperboloid shell; Niteroi Museum)
• Le Corbusier: Beton brut (Unite d'Habitation, Chandigarh — board-marked exposed concrete)
• Zaha Hadid: UHPC and GRC for fluid geometries (Heydar Aliyev Center — GRC panels)
• Grafton Architects: Raw exposed concrete as civic material (UTEC Lima, Bocconi University)

Section 3: Steel

3.1 Structural Steel Grades

ASTM Equivalents: A36 (≈S235), A992 (≈S345-S355), A572 Gr 50 (≈S345)

3.2 Stainless Steel

• 304 (18/8): 18% chromium, 8% nickel. General purpose. Interior and mild exterior use. Yield 210 MPa.
• 316 (18/10/3): Added molybdenum for enhanced corrosion resistance. Marine and polluted environments. Yield 220 MPa. Cost: +30-40% over 304.
• Duplex 2205: High strength (yield 450 MPa) + corrosion resistance. Structural applications. Cost: +50-70% over 304.

3.3 Weathering Steel (Corten A/B)

• Forms stable oxide patina (rust layer) that protects underlying steel
• Eliminates need for painting; self-healing if scratched
• Patina formation: 2-5 years for full development; color progression from orange to deep brown
• Critical: Must not be used where run-off stains adjacent materials (limestone, concrete). Requires detailing to manage staining. Not suitable for marine environments (chloride prevents stable patina).
• Exemplars: Angel of the North (Gormley), Barclays Center Brooklyn (SHoP), CaixaForum Madrid (Herzog & de Meuron)

3.4 Finishes

• Painted: Shop-applied primer + topcoat. Recoat every 15-25 years. Most common.
• Galvanized (hot-dip): Zinc coating 45-85 µm; 40-60 year life in mild environments. Matte silver-grey appearance.
• Powder-coated: Thermoset polymer; color range unlimited; 20-30 year life exterior. Polyester (standard) or PVDF (premium, 30+ years).
• Brushed/Polished: For stainless steel; various grades (No.4 brushed, No.8 mirror).
• Patinated: Applied patina (chemical acceleration of natural oxidation); controlled finish for bronze, copper, steel.

3.5 Key Properties

• Density: 7,850 kg/m³
• Thermal conductivity: 50 W/mK (carbon steel); 16 W/mK (stainless 304) — significant thermal bridging risk
• Elastic modulus: 200-210 GPa
• Embodied carbon: 1.55 kgCO2e/kg (primary/virgin, world average); 0.47 kgCO2e/kg (EAF recycled, 100% scrap). Steel is ~90% recyclable.
• Fire: Loses 50% strength at ~550°C; unprotected steel reaches this in 15-20 minutes in standard fire

3.6 Fire Protection Methods

3.7 Connection Types

• Bolted: Site-assembled; adjustable; demountable (DfD-friendly). High-strength friction-grip (HSFG) bolts M16-M30.
• Welded: Strongest; continuous load path; shop-welded preferred (controlled conditions). Site welding possible but requires NDT.
• Pin joints: True pins (single bolt) allow rotation; used at truss nodes and portal bases.
• Moment connections: Resist rotation; bolted end-plate or welded. Create rigid frames for lateral stability.

3.8 Architects of Steel

• Mies van der Rohe: Expressed steel frame (Farnsworth House, Crown Hall, Seagram Building — bronze-anodized I-beams)
• Norman Foster: High-tech exposed steelwork (HSBC HQ Hong Kong, Millennium Bridge, 30 St Mary Axe diagrid)
• Renzo Piano: Lightweight steel + cable structures (Centre Pompidou with Rogers, Menil Collection)
• Santiago Calatrava: Sculptural steel ribs and masts (City of Arts and Sciences, Milwaukee Art Museum)
• Peter Rice (Ove Arup): Cast steel nodes and tensile structures (Lloyd's of London, Kansai Airport)

Section 4: Timber

4.1 Softwood Species

4.2 Hardwood Species

4.3 Engineered Timber

Glulam (Glued Laminated Timber):

• Laminations: 25-45 mm thick; glued with MUF or PRF adhesive
• Grades: GL24h to GL32h (24-32 MPa bending strength)
• Spans: 6-40 m (beams), up to 100+ m (arches)
• Depth: typically span/15 to span/20 for beams
• Cross-section: 100-600 mm wide, 200-2,400 mm deep
• Can be curved (minimum radius ≈ 175× lamination thickness)

Cross-Laminated Timber (CLT):

• Orthogonal layers (3, 5, or 7 ply); typically spruce
• Panel sizes: up to 3.5 m × 16 m × 500 mm
• Walls: 100-300 mm thick; floors: 140-350 mm thick
• Spans: 4-8 m (floors), 3-4 m (walls for 6+ storey buildings)
• Compressive strength perpendicular: 2.5-3.0 MPa
• Airtightness: inherently airtight at panel body; joints sealed with tape/gaskets

Laminated Veneer Lumber (LVL):

• 3 mm rotary-peeled veneers; all grain parallel (unlike plywood)
• Higher strength than sawn timber of same species: bending 40-65 MPa
• Available as beams, studs, and rim boards
• Consistent, defect-free

Plywood:

• Cross-laminated veneers; balanced layup
• Structural grades: 12-25 mm for sheathing; 18-30 mm for flooring
• Marine plywood: WBP (weather and boil proof) adhesive; tropical hardwood species
• Birch plywood: premium face quality for joinery and furniture

4.4 Key Properties (Generic Softwood)

• Density: 350-550 kg/m³ (kiln-dried at 12% MC)
• Thermal conductivity: 0.13 W/mK (perpendicular to grain) — natural insulator
• Specific heat capacity: 1,600 J/kgK
• Embodied carbon: -1.0 to -1.6 kgCO2e/kg (carbon-negative — sequesters more CO2 during growth than emitted in processing)
• Embodied carbon (CLT panel): approximately -500 to -700 kgCO2e/m³ including sequestration
• Fire performance: Euroclass D (combustible) but predictable charring rate allows fire engineering
• Charring rate: 0.65 mm/min (softwood), 0.50 mm/min (hardwood), 0.70 mm/min (glulam)
• Fire-engineered CLT: 90-120 minute resistance achievable with oversized sections (add 40-60 mm sacrificial charring layer per exposed face)

4.5 Durability and Preservation

EN 350 Durability Classes:

1. Very durable (> 25 years ground contact): teak, iroko, accoya
2. Durable (15-25 years): oak, sweet chestnut, western red cedar
3. Moderately durable (10-15 years): Douglas fir, larch, Scots pine (heartwood)
4. Slightly durable (5-10 years): spruce, pine (sapwood), hem-fir
5. Not durable (< 5 years): beech, ash, birch (untreated external)

Preservation Methods:

• CCA (Copper-Chrome-Arsenic): UC4 ground contact; restricted in EU for non-industrial use
• Copper-based (ACQ, MCQ): residential-approved alternatives to CCA
• Thermal modification: heat treatment (180-230°C) improves durability to Class 1-2; darkens color; reduces strength 10-20%
• Acetylation (Accoya): chemical modification; Class 1 durability; 50+ year warranty above ground; dimensionally stable
• Oil/wax finishes: maintenance coats every 1-3 years for external; UV protection
• Fire retardant treatment: pressure-impregnated salts achieve Euroclass B (limited combustibility)

4.6 Architects of Timber

• Kengo Kuma: Timber as weaving/stacking element (Yusuhara Wooden Bridge Museum, V&A Dundee timber screen concept, Prostho Museum GC — interlocking timber grid)
• Shigeru Ban: Structural innovation (Centre Pompidou-Metz — glulam gridshell; Tamedia Office — interlocking timber frame no metal connectors; Paper Bridge)
• Peter Zumthor: Timber as sensory material (Steilneset Memorial — timber-framed cocoon; Swiss Pavilion Hanover 2000 — stacked timber beams)
• Hermann Kaufmann: Mass timber pioneer (Illwerke Zentrum Montafon — 8 storey CLT/glulam hybrid; LifeCycle Tower)
• Heatherwick Studio: Engineered timber at scale (Maggie's Leeds — timber lattice)

Section 5: Masonry

5.1 Brick

Types:

• Clay brick (fired): Most common; firing temperature 900-1,150°C determines color (buff to deep red to blue-black). Compressive strength 10-150 MPa.
• Calcium silicate (sand-lime): Autoclaved; consistent dimensional accuracy; limited color (white, grey, pastel). Strength 15-50 MPa.
• Concrete brick: Portland cement + aggregate; wide color range with pigments. Strength 7-40 MPa.
• Engineering brick: High-strength (≥ 70 MPa Class A, ≥ 50 MPa Class B) and low water absorption (< 4.5% A, < 7% B). Blue-black color. DPC, retaining walls, below ground.

Standard Sizes:

• UK standard: 215 × 102.5 × 65 mm (coordinating: 225 × 112.5 × 75 mm with 10 mm joints)
• US modular: 194 × 92 × 57 mm (7⅝ × 3⅝ × 2¼ in)
• US standard: 203 × 92 × 57 mm
• Metric modular: 190 × 90 × 57 mm (200 × 100 × 67 mm with joints)
• Roman: 295 × 90 × 40 mm (elongated, thin profile)
• Continental long format: 490 × 90 × 40-52 mm

Bond Patterns:

• Stretcher (running): All stretchers; half-bond offset. Single-leaf walls, cavity wall outer leaf. Most common.
• Flemish: Alternating headers and stretchers in each course. Full-thickness wall; decorative.
• English: Alternating courses of headers and stretchers. Strong cross-bonding; full-thickness wall.
• Stack bond: No offset; vertical joints aligned. Purely decorative (requires reinforcement or veneer application). Modernist aesthetic.
• Herringbone: Bricks at 45° in alternating directions. Decorative infill panels; paviors.
• Monk bond: Two stretchers + one header per course. Variant of Flemish.
• Header bond: All headers; full-thickness wall. Curved walls (radial bonding).

5.2 Stone

5.3 Concrete Block

• Dense block: 2,000-2,200 kg/m³; compressive 7-35 MPa; thermal conductivity 1.0-1.5 W/mK. Structural walls, foundations.
• Lightweight aggregate block: 600-1,400 kg/m³; λ = 0.15-0.50 W/mK. Better insulation, reduced structural capacity.
• Aircrete (AAC — Autoclaved Aerated Concrete): 400-800 kg/m³; λ = 0.10-0.20 W/mK; compressive 2-7 MPa. Non-loadbearing and low-rise loadbearing. Excellent thermal performance. Easy to cut and shape.

5.4 Mortar and Joints

Mortar Designations (BS EN 998-2):

• M2 (1:2:9 cement:lime:sand): weak; heritage and soft brick
• M4 (1:1:6): medium; general brickwork above DPC
• M6 (1:½:4.5): medium-strong; external walls, moderate exposure
• M12 (1:¼:3): strong; engineering brick, retaining walls, below DPC

Joint Profiles:

• Flush: weathering neutral; clean modern appearance
• Bucket handle (concave): good weathering; most common
• Weathered (struck): sloped to shed water; traditional
• Recessed: shadow line aesthetic; poor weathering (not for exposed positions)
• Raked: deep recess for dramatic shadow; worst weathering performance

Embodied Carbon:

• Clay brick: 0.22 kgCO2e/kg (typical); 0.14 (low-carbon production)
• Limestone ashlar: 0.09 kgCO2e/kg
• Concrete block: 0.08-0.12 kgCO2e/kg
• AAC block: 0.28-0.34 kgCO2e/m² (per block face area)

Section 6: Glass

6.1 Glass Types

Float Glass: Basic annealed glass. Breaks into large sharp shards. Not safety glass. VLT 87% (clear 6 mm).

Toughened (Tempered): Heat-treated to 4-5× strength of annealed. Breaks into small granules. Safety glass for doors, balustrades, overhead. Cannot be cut after toughening.

Laminated: Two or more glass plies bonded with PVB or SentryGlas interlayer. Holds together when broken. Safety glass; security; acoustic; UV filtering. Structural glazing interlayer (SentryGlas) enables longer spans.

Insulating Glass Unit (IGU): Two or three panes separated by spacer bars and sealed cavity (air, argon, krypton). U-values: double air 2.8, double argon 1.1-1.3, triple argon 0.5-0.7 W/m²K.

Tinted Glass: Body-colored (grey, bronze, green, blue). Reduces VLT and SHGC. Absorbs solar energy (heats up).

Low-E Coated: Metallic oxide coating reflects long-wave infrared radiation. Soft coat (sputtered, pyrolytic) on surface 2 or 3 of IGU. Reduces U-value by 30-50%.

Solar Control: Selective coating that admits visible light while rejecting solar infrared. VLT:SHGC ratio (selectivity) ≥ 1.5 is good; ≥ 2.0 is excellent.

Fire-Rated: Wired glass (30 min integrity, no insulation); intumescent gel-filled (30-120 min integrity + insulation); borosilicate (integrity only).

Patterned/Textured: Rolled pattern on one surface. Obscured vision with light transmission. Reeded, fluted, hammered, stippled.

Printed/Fritted: Ceramic frit screen-printed and fused to glass surface. Solar shading, bird safety, decoration. Frit coverage 20-60%.

Etched/Sandblasted: Acid or abrasive surface treatment for translucency/privacy. VLT reduction 5-15%.

Dichroic: Vacuum-deposited metallic layers create color-shifting effects. Transmitted and reflected colors are complementary.

6.2 Structural Glass

• Glass fins: Vertical glass blades supporting glazed facades. Toughened + laminated. Depth 150-500 mm; spans 4-12 m.
• Glass beams: Laminated glass beams for roof support. Typically triple-laminated toughened. Spans 3-8 m.
• Glass floors: Laminated toughened panels; minimum 3-ply for redundancy. Anti-slip surface treatment. Design load: 5 kN/m² typical.
• Glass columns: Rare; bundled glass tube columns (Apple Stores); solid glass blocks (Hermes, Tokyo by MVRDV).
• Point-fixed glazing: Stainless steel bolt fittings through drilled holes; spider brackets. Eliminates framing for maximum transparency.

6.3 Key Properties

• Density: 2,500 kg/m³
• Compressive strength: 800-1,000 MPa (rarely governing)
• Tensile strength: 30-70 MPa (annealed); 120-200 MPa (toughened). Glass fails in tension.
• Elastic modulus: 70 GPa
• Thermal conductivity: 1.0 W/mK
• Thermal expansion: 9 × 10⁻⁶ /°C
• Acoustic: single 6 mm pane Rw ≈ 31 dB; laminated 6.4 mm Rw ≈ 34 dB; IGU 4-16-4 Rw ≈ 29 dB (coincidence dip)

6.4 Architects of Glass

• Norman Foster: Structural glass innovation (30 St Mary Axe diagrid, Apple Park, Great Court British Museum — glass roof)
• Renzo Piano: Layered glass skins (Shard, Fondation Beyeler, California Academy of Sciences)
• SANAA (Sejima + Nishizawa): Minimal glass enclosures (New Museum, Rolex Learning Center, Glass Pavilion Toledo — curved glass walls)
• Jean Nouvel: Glass as cultural narrative (Institut du Monde Arabe, Fondation Cartier — transparent layers)
• Apple Stores (Foster + Partners / Bohlin Cywinski Jackson): All-glass structures; glass fins, glass beams, glass stairs

Section 7: Metals and Composites

7.1 Aluminum

• Density: 2,700 kg/m³ (1/3 of steel)
• Tensile strength: 70-310 MPa (alloy-dependent; 6063-T6: 205 MPa)
• Thermal conductivity: 160-200 W/mK (severe thermal bridging; require thermal breaks in window/curtain wall profiles)
• Embodied carbon: 8.2 kgCO2e/kg (primary); 0.5 kgCO2e/kg (recycled). ~75% of all aluminum ever produced still in use.
• Finishes: anodized (10-25 µm; natural silver, bronze, black; 30+ year life), powder-coated (60-80 µm polyester; any color; 20-30 year life), PVDF-coated (premium; 40+ year life)
• Applications: curtain wall mullions and transoms, window frames, cladding panels, standing seam roofing, solar shading louvers

7.2 Zinc

• Density: 7,130 kg/m³
• Self-healing patina: natural zinc develops grey carbonate patina over 5-10 years
• Pre-patinated options: pre-weathered grey, blue-grey, graphite, pigmented
• Thickness: 0.7-1.0 mm for roofing/cladding (standing seam, flat lock tiles, shingles)
• Embodied carbon: 3.1 kgCO2e/kg (primary); largely recyclable
• Minimum slope: 3° (standing seam); 25° (overlapping tiles)
• Lifespan: 80-100 years in moderate climates
• Applications: roofing, wall cladding, rainwater goods, flashings

7.3 Copper and Bronze

Copper:

• Density: 8,900 kg/m³
• Patina progression: bright copper → brown (months) → dark brown (1-3 years) → green verdigris (7-15 years, climate-dependent)
• Pre-patinated and tin-coated options available
• Thickness: 0.6-0.7 mm for roofing; 3-6 mm for sculpture/cladding
• Embodied carbon: 2.7 kgCO2e/kg (primary); 0.5 (recycled)
• Lifespan: 100-200+ years (historical precedent: church roofs 300+ years)
• Applications: roofing, cladding, flashings, rainwater goods, feature panels

Bronze:

• Copper-tin alloy (typically 90/10 or 85/15)
• Rich golden-brown patina; darker than copper
• Used for doors, handrails, window frames, sculptural elements
• Architects: Mies van der Rohe (Seagram Building — bronze I-beams), Carlo Scarpa (Brion Cemetery — bronze gates)

7.4 Titanium

• Density: 4,510 kg/m³ (57% of steel)
• Corrosion resistance: superior to stainless steel in all environments
• Embodied carbon: 14.1 kgCO2e/kg (highest of common metals)
• Cost: 10-20× structural steel per kg
• Surface: matte grey; can be anodized for iridescent color
• Exemplar: Guggenheim Bilbao (Frank Gehry, 1997) — 33,000 m² of 0.38 mm titanium panels; fish-scale cladding; changes color with light and weather

7.5 ETFE (Ethylene Tetrafluoroethylene)

• Density: 1,750 kg/m³ (1% of glass weight per m²)
• Light transmission: 90-95% (clear single layer); 40-60% (printed/fritted)
• Tensile strength: 40-50 MPa (as film, 50-300 µm thick)
• Self-cleaning: non-stick surface; no wash maintenance
• Pneumatic cushions: 2-5 layers inflated at 200-600 Pa; U-value 1.8-3.5 W/m²K
• Lifespan: 25-50 years (UV-resistant fluoropolymer)
• Exemplars: Eden Project (Grimshaw), Allianz Arena (H&dM), Beijing Aquatics Center (PTW), Khan Shatyr (Foster)

7.6 GRP/FRP (Glass/Fibre Reinforced Polymer)

• Density: 1,500-2,000 kg/m³
• Tensile strength: 100-400 MPa
• Thermal conductivity: 0.3 W/mK (thermally non-conductive; no thermal bridging)
• Corrosion-immune; no maintenance
• Moldable to any shape (curved panels, ornamental elements, replica heritage details)
• Applications: cladding panels, window surrounds, cornices, columns (replica stone/timber appearance)

7.7 Terracotta

• Clay-based; extruded or pressed; fired at 1,000-1,200°C
• Rainscreen cladding: extruded hollow sections; 20-40 mm thick; back-ventilated cavity
• Baguettes: horizontal or vertical tubular/blade elements for solar shading and facade articulation
• Glazed terracotta: vitreous surface coating; colors unlimited; self-cleaning
• Density: 1,800-2,100 kg/m³
• Fire: Euroclass A1 (non-combustible)
• Embodied carbon: 0.45 kgCO2e/kg
• Exemplars: Natural History Museum London (Waterhouse), Renzo Piano (Central St Giles London — colored terracotta), MVRDV (Markthal Rotterdam — printed terracotta arches)

7.8 Ceramic Tiles and Cladding

• Porcelain: absorption < 0.5%; frost-proof; 12-20 mm thick large format (up to 1.6 m × 3.2 m)
• Stoneware: absorption 0.5-3%; good durability; glazed or unglazed
• Earthenware: absorption > 3%; interior only; hand-decorated (zellige, azulejo)
• Fire: Euroclass A1
• Applications: facade cladding (ventilated rainscreen), floor/wall finishes, pool surrounds

Section 8: Life-Cycle Assessment (LCA)

8.1 Whole-Life Carbon

Total carbon = Embodied carbon (A1-A5, B1-B5, C1-C4) + Operational carbon (B6-B7)

As buildings become more energy-efficient, embodied carbon becomes the dominant component (50-80% of whole-life carbon for Passive House-standard buildings).

8.2 LCA Stages (EN 15978)

Product Stage (A1-A3):

• A1: Raw material extraction
• A2: Transport to manufacturer
• A3: Manufacturing
• This is the "cradle-to-gate" embodied carbon — most commonly reported

Construction Stage (A4-A5):

• A4: Transport to site
• A5: Construction/installation process (energy, waste, temporary works)

Use Stage (B1-B7):

• B1: Installed product use (e.g., carbonation of concrete)
• B2: Maintenance
• B3: Repair
• B4: Replacement (components with shorter life than building)
• B5: Refurbishment
• B6: Operational energy use
• B7: Operational water use

End-of-Life Stage (C1-C4):

• C1: Deconstruction/demolition
• C2: Transport to disposal/recycling
• C3: Waste processing
• C4: Disposal (landfill)

Beyond Life (Module D):

• Credits for reuse, recycling, energy recovery
• Reported separately (not added to A-C total)
• Steel recycling credit: -1.3 to -1.5 kgCO2e/kg
• Timber reuse/energy recovery credit: variable

8.3 Embodied Carbon Benchmarks

LETI (London Energy Transformation Initiative) Targets:

RIBA 2030 Climate Challenge:

• 2020: < 600 kgCO2e/m² (A1-A5)
• 2025: < 450 kgCO2e/m²
• 2030: < 300 kgCO2e/m²

IStructE Targets (structure only):

• Residential: < 300 kgCO2e/m² (typical); < 200 (best practice)
• Office: < 350 kgCO2e/m² (typical); < 250 (best practice)
• Best-in-class timber buildings: < 150 kgCO2e/m² (structure)

8.4 Material-Level Embodied Carbon

8.5 Material Passports and Circular Economy

Material Passport: Digital record of all materials and components in a building — type, quantity, location, quality, toxicity, recyclability. Enables future recovery and reuse.

Circular Economy Principles for Architecture:

1. Design for Longevity: durable materials, adaptable layouts
2. Design for Disassembly (DfD): bolted connections (not welded/glued), layered construction (facade independent of structure), accessible fixings
3. Design for Reuse: standard sizes, undamaged removal, material banks
4. Use Recycled Content: specify minimum recycled content in steel (90%+ achievable), aluminum (50%+), concrete aggregate (20-30% RCA)
5. Use Renewable Materials: timber, bamboo, hemp-lime, straw, earth
6. Eliminate Waste: modular coordination, prefabrication, digital cutting optimization

Exemplars of Circular Design:

• Triodos Bank HQ (RAU Architects, 2019, Driebergen) — timber structure fully demountable; bolted steel connections; every element logged in material passport (Madaster platform)
• Park 20|20 (William McDonough, Amsterdam) — cradle-to-cradle certified; demountable facades; material passports for all buildings