LC Construction Studies cheat sheet

Planning permission is required for development as defined in planning law; exempted development (e.g. some small domestic extensions within floor-area and height limits) does not require permission but must still comply with building regulations.

Site analysis records orientation, prevailing wind, noise sources, access, drainage, levels, and services; a site survey should show boundaries, contours, and existing features before design begins.

Sun path: in the northern hemisphere the sun rises in the east, is due south at solar noon, and sets in the west; a south-facing facade receives the highest annual solar gain.

Plot ratio = gross floor area ÷ site area; site coverage = footprint area ÷ site area. Both are set by zoning or local development plans.

Ground investigation typically progresses desk study → trial pits or boreholes → laboratory testing; the soil report informs foundation choice and safe bearing pressure.

Flood risk assessment classifies sites by return-period probability; development in floodplains requires attenuation or raised finished floor levels.

Sight lines and access: driveway gradients are typically limited to about 1:20 near the road and visibility splays must be kept clear of obstructions.

Radon, contaminated land, and archaeological potential are desk-study checks that can trigger mitigation or preservation conditions on a grant of permission.

Density (kg/m³) governs self-weight and acoustic mass; typical values: concrete ~2400, brick ~1900, softwood ~500, steel ~7850.

Thermal conductivity λ (W/m·K) is a material property; lower λ means better insulation. Thermal resistance R = thickness ÷ λ; U-value = 1 ÷ sum of resistances.

Concrete characteristic cube strength (e.g. C25/30) is the 28-day strength in N/mm²; the first number is cylinder strength, the second cube strength.

Steel is strong in tension and compression but needs fire protection, as strength falls sharply above roughly 550 °C; concrete spalls and timber chars at a predictable rate.

Timber is anisotropic: strength is greatest parallel to grain; moisture content causes shrinkage, so timber should be dried to near service conditions before fixing.

Mortar and render must be weaker and more permeable than the masonry they protect, so movement and moisture release occur in the sacrificial layer.

Damp-proof course (DPC) resists rising moisture in walls; damp-proof membrane (DPM) does the same under ground floors. Both are impermeable barriers, not sealants.

Material selection balances strength, durability, fire reaction, thermal performance, embodied carbon, cost, and availability; no single property decides a specification.

Traditional strip foundations suit firm subsoil; raft foundations spread load over weak or variable ground; piles transfer load to deeper bearing strata.

Cavity walls use two leaves tied with wall ties, a cavity (typically 100–150 mm) partly or fully filled with insulation, and weep holes above flashings.

Timber frame walls rely on sheathing board for racking resistance; a ventilated cavity and breather membrane protect the frame from driving rain.

Roof pitch must exceed the minimum for the covering: natural slate typically needs 35° or more, plain tiles about 35°, and profiled sheeting can go much lower.

A cold roof ventilates the loft above the insulation; a warm roof places insulation above the deck, keeping the structure warm and removing the need for through-ventilation.

Floor buildup: ground floor = hardcore, sand blinding, DPM, insulation, concrete slab, screed or finish; upper floor = joists or beam-and-block with deck.

Fire compartmentation uses fire-resisting walls, floors, and doors with intumescent strips and smoke seals; services penetrating compartments need fire stops.

Stair design: two rises plus one going should total roughly 550–700 mm; a typical domestic riser is 150–220 mm and going 220–300 mm.

Loads divide into dead (self-weight), live/imposed (occupancy), and environmental (wind, snow); design combines them with partial safety factors.

Equilibrium requires sum of vertical forces, horizontal forces, and moments each to be zero; overturning resistance comes from weight and lever arm.

Bending moment M and shear V in a simply supported beam under uniform load w over span L: Mmax = wL²/8, Vmax = wL/2.

Bending stress σ = M ÷ Z, where Z is the elastic section modulus; deflection limits are span/360 for many floors and span/250 for roofs.

Triangulation gives stability: braced frames, diagonal bracing, and shear walls resist lateral loads; a rectangular frame without bracing is a mechanism.

Slenderness ratio = effective length ÷ radius of gyration; higher slenderness lowers compressive resistance, so columns need restraint in both axes.

Wind pressure acts on the exposed area and increases with height and exposure; uplift on roofs must be resisted by ties and hold-down fixings.

Foundations must keep bearing pressure below the safe bearing capacity of the soil and limit differential settlement to avoid cracking.

Embodied carbon is the total emissions from extraction, manufacture, transport, construction, and end of life; operational carbon is emissions in use.

A building's operational energy is dominated by space heating, domestic hot water, lighting, and appliances; fabric performance reduces heating demand first.

Thermal bridging at junctions raises heat loss; a continuous insulation layer and accredited details (e.g. psi values) reduce it.

Airtightness is measured in air changes per hour at 50 Pa (m³/h·m²); good practice targets around 3–5, with passive standards below 1.

Overheating risk is assessed with solar gain, glazing ratio, orientation, thermal mass, and purge ventilation; west-facing glazing causes late-afternoon peak gains.

Life cycle assessment sums impacts across a building's life; reuse and recycling of materials lower end-of-life impact.

Sustainable drainage (SuDS) manages rainwater through attenuation, infiltration, and flow control, reducing flood risk and pollution.

On-site renewable options include solar thermal, photovoltaics, heat pumps, and biomass; each has output profiles that must match demand.

A heat pump's efficiency is expressed as coefficient of performance (COP), the ratio of heat delivered to electrical energy input; higher flow temperatures lower COP.

Ventilation types: natural (stack and wind driven), mechanical extract, and mechanical ventilation with heat recovery (MVHR), which recovers typically 70–90% of exhaust heat.

Water supply: cold water storage cisterns, boosted or mains-fed systems, and hot water cylinders; a typical domestic supply pressure is around 1–3 bar.

Rainwater harvesting reduces mains demand for non-potable uses such as WC flushing and irrigation; it needs filtration and storage.

Greywater and SUDS support water efficiency; low-flush WCs and aerated taps reduce demand directly.

Renewable heat incentives and building energy ratings (BER) reward fabric-first design, efficient services, and renewable contribution.

Electrical services include distribution boards, protective earthing, residual current devices, and circuit separation; final circuits are sized for load and volt drop.

Commissioning and building logbooks record as-built performance so that design intent survives handover.

U-value = 1 ÷ (Rsi + R1 + R2 + … + Rse); units are W/m²·K, and a lower U-value means better thermal performance.

R = d ÷ λ, where d is layer thickness in metres and λ is thermal conductivity in W/m·K.

Standard surface resistances: Rsi about 0.13 m²·K/W for walls and 0.17 for roofs; Rse about 0.04 m²·K/W.

Fabric heat loss = Σ(U × A) × ΔT; ventilation heat loss = 0.33 × n × V × ΔT, where n is air changes per hour and V is room volume.

Degree days estimate seasonal heating energy: energy ≈ (U × A) × degree days × 24 ÷ 1000, in kWh.

Condensation risk: warm moist air meeting a cold surface below dew point condenses; interstitial condensation needs a vapour control layer on the warm side.

Thermal mass moderates temperature swings; it is useful only when coupled to the occupied space and exposed to solar gain.

Heat loss from pipework and ducts is reduced by insulation; uninsulated hot water cylinders and pipe runs waste energy continuously.

Standard scales: 1:1 for details, 1:5 and 1:10 for construction details, 1:50 and 1:100 for plans and sections, 1:200 and 1:500 for site plans.

Orthographic projection uses plan, elevation, and section together; first-angle and third-angle layouts place views differently, so state the convention.

A section cuts the building and shows structure and construction; an elevation shows only the external face, with hidden detail omitted.

Dimensioning rules: give overall and setting-out dimensions, avoid duplication, and keep dimensions on a consistent side of the drawing.

Conventions: solid lines for visible edges, dashed for hidden, centre lines for axes, and hatching for cut materials.

A drawing register and title block record project, drawing number, scale, revision, and date; revisions must be traceable.

In an applied design project, the brief sets the client needs and constraints, and the design must be shown to satisfy them through drawings and a written justification.

Schedules (doors, windows, finishes) complement drawings; a window schedule records type, size, glazing, and ironmongery.