Construction Technology & Environmental Services Flashcards
Tell me about 2 different foundation types
a. Strip: Shallow continuous excavation filled with reinforced concrete for perimeter/internal walls. Suitable for most subsoils and light structures.
b. Pile: Deep cylindrical excavations filled with steel or reinforced concrete to transfer building loads deep into the ground.
What are the common factors which affect the selection of these foundation types?
a. Type of foundation (deep or shallow)
b. Building load
c. Proximity of trees/roots
d. Soil type and bearing capacity
e. Soil plasticity
f. Proximity of rivers
What is BS8004?
Code of practice for foundations
What is depth of foundations of clay soils?
a. Low shrinkage clay: Min 750mm
b. Medium shrinkage clay: Min 900mm
c. High shrinkage clay: 1m (more if trees are nearby)
What are clay soils?
a. Heavy soil with >30% fine clay particles and little organic material
b. Becomes plastic when wet, poor drainage
c. Expands and shrinks due to moisture changes
What is the depth of foundations to avoid frost heave?
Minimum of 450mm below ground level
What is the dimension of a brick and block?
Brick: 215mm × 65mm × 102.5mm
Block: 440mm × 215mm × 100mm
What are the differences between early/modern cavity walls?
a. Early: Two brick skins, 50mm cavity, no insulation
b. Modern (post-1970s): Brick outer skin, block inner skin, 75–100mm cavity with 25mm insulation
c. Pre-1981 walls used mild steel ties prone to corrosion
Wall tie spacing?
450mm vertical, 900mm horizontal
Around openings: 225mm from edge, 300mm vertical spacing
How would you determine what foundation type to use with different soils?
Soil testing for bearing capacity, settlement analysis, and moisture content
How would you determine what foundation type to use with different building types?
Depends on building’s weight, size, and type
Shallow for low-rise, deep for high-rise
What different construction types are there?
a. Traditional - solid wall and cavity
b. System build - Crosswall, Reema, Orlit, No fines, Ring beam
Explain the makeup of a no fines wall
a. System build type
b. In-situ concrete mix of large aggregates, cement, and water
c. Porous, lightweight, with thermal insulation properties
What different roof types are there?
Pitched, flat, cut, truss, mansard
What is the makeup of a warm roof?
Joists, deck, vapour barrier, insulation, roof covering
What is the makeup of a cold roof?
Insulation between joists, deck, air gap for ventilation, roof covering
Advantages and disadvantages to a warm roof?
Pros: Continuous warmth, no cold spots, prevents condensation, tapered insulation possible
Cons: Higher roof profile, costlier, more complex
Advantages and disadvantages to a cold roof?
Pros: Thinner profile
Cons: Needs ventilation, risk of timber rot, cold bridging, harder to check insulation
Differences between a warm and cold roof?
Cold: Insulation within joists, vapour barrier below deck, ventilation required
Warm: Insulation above deck, vapour barrier above deck, no ventilation needed
What systems does the superstructure support?
Roof, external walls, windows, doors, HVAC, electrical, plumbing
What are the benefits and disadvantages to solar gain?
Pros: Energy efficiency in winter, lower bills, more natural light
Cons: Overheating, need for cooling, night-time heat loss, material degradation
How do different elements of a building link together?
Via structural framework, connections, service installations, and finishes
What is portal frame?
Steel/concrete frames with rigid joints between columns and rafters; used in industrial/commercial buildings
What are the benefits and disadvantages to a portal frame building?
Pros: Cost-effective, spacious, flexible layout, fast to build
Cons: Poor thermal performance, less compartmentation, heavy materials need complex foundations
