🔄 Auto Ring Optimization: The system automatically selects the best combination of 1000mm, 750mm, 500mm, and 250mm rings to minimize the total number of rings required.

📐 Manhole Depth Breakdown:

📏 Duct Bank Configuration:
• Sand bedding beneath ducts (typically 150mm)
• Spacing between ducts (typically 100mm)
• Sand surround above ducts (typically 150mm)
• Backfill from top of sand to ground level

📐 Duct Bank Breakdown:

📏 UK Standard Kerb Types:
• HB2 (Half Battered): 125mm × 255mm - Most common for roads
• HB1 (Half Battered): 150mm × 305mm - Heavy duty roads
• BN (Bullnose): 150mm × 305mm - Pedestrian/decorative areas
• Flat Top: 125mm × 150mm - Light duty/industrial

📐 Kerb Installation Breakdown:

🏗️ What are you building?

Select your formwork type and we'll set up the calculator with the right defaults

📐 UK Formwork Standards:
• Plywood: Marine ply (exterior grade) or phenolic shutterply for concrete formwork
• Walings: Horizontal timber supports (typically 100×50mm at 600mm centres)
• Soldiers: Vertical timber supports (typically 100×50mm at 450mm centres)
• Props: Acrow props support slabs (1.2m grid) or walls (1.5-2m spacing)
• Ties: Through-ties or snap ties to hold formwork together (600mm grid)
• Release Agent: Oil or proprietary release agent for easy stripping

Props Calculation:
• Slabs/Soffit: Props in grid pattern (Length ÷ Spacing) × (Width ÷ Spacing)
• Walls: Props at spacing intervals along length to support walings
• Columns: Minimum 4 props at corners, more for larger perimeters

📋 Materials Breakdown:

📏 UK Kerb Standards:
• Bedding: Concrete foundation beneath the kerb (typically 100mm deep × 300mm wide)
• Backing (Haunch): Concrete support behind the kerb to prevent tipping (typically 150mm × 150mm)
• Standard Length: 915mm (3ft) is most common, with shorter units for curves

📏 Kerb Dimensions:
• Standard Kerb Length: 915mm (0.915m)
• Dropped Crossing: 780mm (0.780m)
• Foundation: Typically 300mm wide × 150mm deep
• Backing: Typically 150mm wide × 150mm high behind kerb

🛣️ UK Tarmac Standards (BS 594987:2024):
• Sub-Base: DOT Type 1 (150-225mm) - well compacted foundation
• Binder Course: AC20 bin (45-105mm) - structural strength layer
• Surface Course: AC6/AC10 surf (20-40mm) - wearing layer
• Materials: SMA (high traffic), HRA (durability), AC (general use)

📐 Build-up Specification:

📏 Common Applications:
• Concrete slabs, footings, and foundations
• Wall rendering and plastering
• Paint coverage and decorating
• Material quantities for floors, walls, and roofs

📐 Calculation Details:

🪨 Material Categories:
• Type 1/MOT: Sub-base for roads, blocks, hard core (limestone, crushed concrete, granite)
• Sand: Sharp, building, washed recycled, reject sand for various applications
• Gravel: Decorative and functional - 6mm to 40mm sizes
• Topsoil: Horticultural, enriched, mulch, premium, turfing soil
• Ballast: Concreting, sub-base, driveways - 0-10mm to screened types
• Specialist: 6F2, Type 3, tarmac plainings, gabion fill, granite dust

📐 Material Information:

📊 Calculation Breakdown:

🟫 Paving Types:
• Concrete Slabs: Standard paving slabs in various sizes
• Porcelain Paving: Premium porcelain tiles for outdoor use
• Natural Stone: Indian Sandstone, Limestone, Granite, Slate
• Paving Sets: Setts, cobbles, block paving

📐 Paving Specification:

📊 Installation Notes:

💡 Pricing Library: These rates auto-apply to BOQ calculations. Update them to match your local suppliers or current market rates. All prices are in GBP (£).