Requirements:

• Obtain a site-specific geotechnical report before design: soil classification, bearing capacity, groundwater level, seasonal groundwater variation, frost depth, swelling/shrinkage potential, and contamination screening.
• Design foundation type and depth to suit bearing capacity and groundwater: use shallow foundations where soils are competent; where soft soils exist consider ground improvement, piles or raft foundation.
• Account for frost depth and potential for frost heave: place slab/foundation bottoms below local frost penetration or provide adequate insulation/frost protection.
• Provide drainage strategy and groundwater control for the chosen foundation: include perimeter drains, sump pumps, or temporary dewatering for construction as required.
• Identify site-specific risks (collapsible soils, peat, high sulphates, expansive clays) and require mitigation in the geotechnical report.

Requirements:

• Ensure structural design follows basic Eurocode workflow: basis of design, actions, geotechnical input, and limit/state checks. Engage a structural engineer for slab or basement design.
• Check slab thickness and reinforcement based on loads and soil: typical residential ground slabs often range ~120–250 mm; heavier imposed loads, frost protection, or poor soils may require thicker slabs or structural rafts—confirm by calculation.
• Specify reinforcement: mesh or distributed reinforcement with correct cover (minimum concrete cover to reinforcement as per exposure class), bar sizes and spacing determined by EN 1992 calculations.
• Design edge beams, ground beams and strip footings to transfer loads to the subsoil; include adequate continuity, dowels and construction joints as required.
• Check load-bearing capacity and serviceability (deflection/cracking) for live, dead and environmental loads per EN 1991 and EN 1992.
• Include construction details for jointing, movement joints, control joints and slab-to-wall connections to prevent uncontrolled cracking.

Requirements:

• Set target floor U-value consistent with national energy regulations or desired energy class. For retrofit/low-energy homes, aim for low U-values (e.g., ≤0.20 W/m²K where guidance permits); verify national targets.
• Specify continuous perimeter insulation to reduce thermal bridging at slab edges: ensure minimum thickness and material (e.g., rigid XPS/PIR) with a thermal break at slab-wall junctions.
• Detail insulation under slab where required: include compressive strength rating for below-slab insulation and protection from moisture/installation damage.
• Include capillary and vapour control layers beneath the slab (DPM/vapour barrier) and ensure continuity between floor and wall barriers.
• Perform thermal bridging and hygrothermal checks at critical nodes (slab edge, junctions, service penetrations) using EN ISO 10211/EN 15026 methodology where required.
• Ensure floors that are part of the thermal envelope are integrated into heating system design and condensation risk is assessed.

Requirements:

• Design perimeter drainage to carry groundwater away from foundations: include gravel drains, geotextile filters and connection to a suitable outfall or sump.
• Protect footings and slabs from frost action by setting foundations below local frost depth or by providing edge/foundation insulation.
• Include capillary break (e.g., crushed stone layer) below slabs and a continuous damp-proof membrane (DPM) to prevent rising moisture.
• Specify ground gas protections where required (radon, methane): use membranes, sealed junctions and passive/active venting as per site risk.
• Plan for long-term maintenance access to drainage and sump systems and ensure inspection points are accessible.

Requirements:

• Select waterproofing strategy based on groundwater risk: for high groundwater use fully tanked solutions (inverted or external membrane systems) or bentonite systems; for moderate risk use external membranes with perimeter drainage.
• Specify product type, detailing and protection: choose flexible sheet membranes, bentonite or liquid-applied systems with documented suitability for below-ground use and provide protective boards or geotextiles to avoid damage during backfill.
• Detail continuity of waterproofing at wall-to-slab junctions, service penetrations, movement joints and around sump pits—use manufacturer-approved details and competent installers.
• Provide a robust vapour/permeance strategy: where tanking is used ensure internal condensation risk is checked and ventilation considered.
• Document testing and inspection: water tests, continuity tests, or inspection reports before backfilling. Keep as-built records and membrane certificates for future reference.

Requirements:

• Assess radon risk from site surveys and national radon maps. Where risk exists, include a continuous radon membrane and provision for passive depressurisation.
• Provide a continuous sealed membrane under the slab with sealed joints and route venting ducts to roof level or to a safe discharge point; allow space for retrofit fan installation if active systems become necessary.
• Ensure service penetrations are gas-tight or use proprietary sealed boots and detail all junctions to maintain integrity of the radon barrier.
• Test post-construction for radon concentrations as per national guidance and take corrective action if levels exceed national reference levels.

Requirements:

• For crawl spaces provide a clear strategy: ventilated crawl spaces require adequate vent area and airflow paths; sealed conditioned crawl spaces require continuous vapour control, insulation at perimeter and a mechanical ventilation strategy.
• Specify minimum clear heights and access openings for crawl spaces to allow maintenance (typical minimums vary by country—confirm local codes).
• Design basement egress (escape windows/doors) in habitable basements to meet means-of-escape and daylighting requirements in national regs.
• Detail damp-proofing, insulation and internal finishes for basements intended as habitable space and ensure damp and mould risks are mitigated by vapour control and ventilation.
• Include safety measures during excavation and construction: temporary shoring, competent contractor for confined-space work, monitoring for groundwater, and fall/protection measures.

Requirements:

• Confirm required planning permissions and building permits for foundation type with the local authority before works commence.
• Submit geotechnical report, structural calculations and waterproofing strategy as part of statutory approvals if required locally.
• Schedule and document compulsory inspections: foundation layout, reinforcement before pour, waterproofing/membrane continuity before backfill, and post-construction tests (waterproofing, radon, drainage).
• Keep as-built drawings, product datasheets, certificates and inspection reports for handover and future maintenance.
• Use certified installers for specialised systems (tanking, bentonite, radon membranes) and ensure warranties and latent defect periods are clearly documented.

Requirements:

• Example — Insulated slab-on-grade for a low-energy house: geotech report confirms suitable bearing strata, 200 mm compacted sub-base with capillary break, 120 mm concrete slab with DPM, 150 mm EPS perimeter insulation with thermal break at wall junction, continuous perimeter drainage, and structural mesh 150 x 150 mm with 25 mm cover. Confirm U-value target with thermal calc.
• Example — Crawl space (vented): place footing below frost depth, ventilated vents sized per national rules, ground membrane and 100–200 mm compacted granular layer, accessible hatch and inspection path, ensure vents are not blocked by landscaping.
• Example — Tanked basement in high groundwater: design external membrane to full height below ground with protection board, perimeter drainage to sump with high-capacity pump and alarm, sealed radon membrane, service penetration seal details, and water-tight internal junctions between wall and slab.
• On-site checking list: verify geotech report on site, check excavation depth and side slopes, confirm reinforcement type/spacing and concrete cover before pour, inspect membrane continuity and protection before backfill, take photographs and obtain sign-off certificates.

Requirements:

• Manage excavation risks: use competent contractors, temporary works design for shoring/retaining, monitor groundwater and adjacent structures for movement.
• Ensure confined space procedures for basements/crawl spaces: atmosphere testing, permits-to-work, emergency rescue plan and trained personnel.
• Protect workers and future occupants from moisture, mould and vapour risks by adhering to vapour barrier and ventilation specifications.
• Mitigate electrical and servicing risks where sump pumps, underfloor heating or mechanical systems are used: use suitable IP-rated equipment and provision for safe access and maintenance.
• Plan for climate change resilience: consider higher groundwater scenarios and increased intense precipitation in drainage/waterproofing design.