Continuous Wall Foundation Calculator 2026
Strip footings (continuous footings) support load-bearing walls by distributing loads along a continuous concrete strip beneath the wall length. UK Building Regulations require strip foundations to meet minimum width, depth, and thickness specifications based on building load and ground conditions per Approved Document A.
Minimum Dimensions: Strip footings must be at least 600mm wide for standard residential construction, with concrete thickness of 150-200mm for single storey and 200-250mm for two storey buildings. Foundations must project minimum 150mm either side of the wall they support. Total depth must reach at least 450mm below finished ground level protecting against frost heave, with typical depths ranging 0.9-1.2 metres depending on soil conditions.
Width Requirements: Foundation width varies by ground conditions and total load per linear metre. Good bearing capacity soil (over 100kN/m²) supports 600mm width for single storey, while poor ground requires wider footings up to 900mm or engineered solutions. Two storey buildings typically need 600-750mm width, while three storey or commercial buildings require structural engineer calculations.
Calculate strip footing concrete volume using formula: Volume (m³) = Length (m) × Width (m) × Depth (m). Measure total perimeter length including all external walls plus internal load-bearing walls. For example, house with 40m total footing length, 600mm (0.6m) width, and 200mm (0.2m) concrete depth: 40 × 0.6 × 0.2 = 4.8m³. Add 10% wastage for excavation irregularities: 4.8 × 1.1 = 5.28m³ to order.
| Building Type | Min Width | Concrete Depth | Total Depth |
|---|---|---|---|
| Single Storey | 600mm | 150-200mm | 900-1000mm |
| Two Storey | 600-750mm | 200-250mm | 1000-1200mm |
| Three Storey | 750-900mm | 250-300mm | 1200mm+ |
| Trench Fill | 450-600mm | Full depth | 500mm minimum |
Ready-mix concrete C25/30 grade costs £75-100 per m³ delivered. Typical 4-bedroom house requiring 5m³ concrete costs £380-500 for materials. Excavation costs £8-15 per m³ using machine, £15-25 per m³ manual digging. Groundworker labour charges £150-250 per day with 2-3 days typical for standard house footings. Building control fees add £200-500. Total strip foundation costs range £80-150 per linear metre including all works.
UK Building Regulations specify 600mm minimum width for standard residential strip footings supporting single storey buildings on good ground conditions. Two storey buildings require 600-750mm width, while three storey needs 750-900mm. Footings must project minimum 150mm either side of supported wall. Poor ground conditions require wider footings determined by structural engineer calculations based on soil bearing capacity.
Strip footings must reach minimum 450mm below finished ground level per UK Building Regulations protecting against frost heave. Typical depths range 900-1000mm for single storey, 1000-1200mm for two storey buildings. Concrete thickness within trench should be 150-200mm minimum for single storey, 200-250mm for two storey. Total depth depends on soil conditions, water table, and foundation design.
Use formula: Volume (m³) = Length (m) × Width (m) × Concrete Depth (m). Measure total footing length including perimeter and load-bearing internal walls. Example: 40m length × 0.6m width × 0.2m depth = 4.8m³. Add 10% wastage giving 5.28m³ to order. Standard ready-mix trucks deliver 6m³, so one truck suffices for this example with minimal excess.
Use C25/30 grade concrete minimum for strip footings per BS 8500 standards. This provides adequate strength and durability for typical UK ground conditions. Foundation concrete requires medium workability slump (50-100mm) for proper compaction. Sulphate-resistant cement necessary in aggressive ground conditions with high sulphate content. Always verify ground conditions through trial pits or soil investigation before specifying concrete grade.
Standard strip footings on good ground typically don't require reinforcement if properly designed with adequate width and depth. However, reinforcement becomes necessary for: poor ground conditions, high loads, sloping sites, wide footings exceeding 1 metre, or where structural engineer specifies. Use A142 or A193 steel mesh or 12mm bars at 200mm centres where reinforcement required. Always follow structural engineer specifications for reinforced foundations.
Strip footings cost £80-150 per linear metre in UK including excavation, concrete, labour, and building control. Materials account for £40-60 per metre (concrete £30-40, hardcore £5-10, reinforcement if needed £5-10). Labour costs £30-60 per metre for excavation, placing concrete, and finishing. London and South East command 20-30% premiums, while North and Midlands offer 10-15% savings versus national averages.