OBRAS ONSITE · free site calculators · the pocket book

Trade Measures

The numbers you work out on a scrap of ply - buckets per cube, bags per pour, sheets per wall, beads per cartridge. All budget figures: your product's data sheet and the drawings win.

🪣 Buckets & barrows per m³

Volume (m³)

10 L / 15 L / 20 L buckets · 65 L standard barrow, 100 L big barrow. Heaped loads carry more - these are struck-level.

🪨 Concrete by the bag

Volume (m³)

20 kg premix yields ≈ 0.0092 m³ (≈108 bags per m³). Over ~0.5 m³, order a mini-mix truck - your back will thank you.

⚗ Mix ratios by bucket

Mix Buckets of cement

Same bucket for everything, struck level. Yield ≈ 2/3 of combined dry volume once mixed and compacted.

🎨 Paint

Area (m²) Coats Coverage

Cans: 1 L / 4 L / 10 L. New plasterboard needs its sealer coat first.

🪤 Tiles + adhesive + grout

Area (m²) Tile size Waste

Adhesive ≈ 3.5 kg/m² (6 mm notch; double for 10 mm/large format). Grout by the standard joint formula at 3 mm joints.

📜 Plasterboard

Wall length (lineal m)Wall height (m)Openings (m²) Sheet length

Sheets are 1200 wide - plasterboard is ordered by the lineal metre. Pick a sheet length that covers the wall height in one, or you have added a horizontal butt joint to set and sand. Screws ≈ 30/sheet on walls · stud adhesive 1 tube per 2-3 sheets · base + top compound ≈ 0.5 kg/m². Includes 7% cut waste. Confirm sheet availability with your supplier.

🧱 Render

Area (m²) Thickness

1 : 4 mix · wet volume + 25% for waste/suction. Sand ≈ 1.6 t/m³, cement ≈ 8 bags (20 kg) per m³ of render.

🪖 Decking boards

Deck area (m²) Board

Lineal metres incl. 10% waste · 2 screws per board per joist, joists at 450 crs.

🔭 Skirting & architrave

Room perimeter (m) Doorways

Skirting = perimeter − 0.9 m per doorway + 10%. Architrave ≈ 5.2 LM per single door (both sides).

💧 Silicone & sealant

Joint length (m) Bead

300 ml cartridge. 6 mm bead ≈ 10.6 m, 10 mm ≈ 3.8 m, 12 mm ≈ 2.6 m per cartridge.

🌡 Insulation batts

Area (m²) Coverage per pack

Coverage varies by brand and stud spacing - check the pack label; 5% waste included.

🌱 Soil, mulch & turf

Area (m²) Depth

Turf counted as 1 m² slabs +5% waste (roll sizes vary by supplier - divide by your roll's m²). Soil ≈ 1.4 t/m³, mulch ≈ 1.2 t/m³.

🚶 Ramp gradient checker

Rise (mm) Run (mm)

Accessible walkway 1:20 · access ramp max 1:14 (AS 1428.1) · kerb ramp 1:8 short only. Verify against the standard and your certifier.

🪛 Stair rise & going

Total rise (mm) Going per tread (mm)

NCC (houses): riser 115-190 mm, going 240-355 mm, 2R+G between 550-700. Check your class of building and the certifier's word is final.

More: Concrete pour · Reo & mesh · Brick & block · All free tools →