Calculator
Formula Used
- Net deck area =
length × width − void_area - Module size =
(paver_length + gap) × (paver_width + gap) - Base pavers =
net_area ÷ module_area - Total pavers =
ceil(base × complexity × (1 + waste%)) - Pallets =
ceil(total_pavers ÷ pavers_per_pallet)
- Total weight =
total_pavers × weight_per_paver - Weight per area =
total_weight ÷ net_area - Pavers cost =
total_pavers × price_per_paver - Labor cost =
net_area × labor_rate - Total cost =
(pavers + labor + delivery) + tax
How to Use This Calculator
- Pick a unit system and enter deck length and width.
- Subtract openings like planters or skylights as void area.
- Enter paver size and the joint gap you expect to keep.
- Choose a complexity level and a waste percentage.
- Add pallet, weight, and pricing details for delivery planning.
- Press Submit, then download CSV or PDF if needed.
Net Area and Module Planning
Start by measuring deck length and width, then subtract openings for planters, drains, and skylights. The calculator converts those inputs into a net working area and divides it by a “module” area. The module is the paver size plus the joint gap in both directions, which mirrors real installation spacing and prevents under-ordering. Common gaps run 3–6 mm or 1/8–1/4 inch.
Waste and Layout Complexity Benchmarks
Waste is not a guess; it reflects cuts, breakage, and future replacements. Straight runs with minimal obstacles often succeed with 5–8% waste, while planter edges or step-backs commonly need 8–12%. Diagonal or multi-zone patterns can exceed 12%. The built-in complexity factor (1.00, 1.03, 1.06) adds a controlled buffer for tricky perimeters and repeated corner cuts.
Weight and Roof Loading Awareness
Pavers add dead load that stays on the structure year-round. A typical 24×24 unit can range from about 30–45 lb (14–20 kg), and smaller 16×16 pieces often fall near 18–28 lb (8–13 kg). Use manufacturer weights whenever possible. The calculator estimates weight per area, then compares it to an optional limit so you can flag risky designs early. Remember to add pedestal, mat, and furniture weight.
Pallet, Handling, and Staging Logistics
Knowing pallet count helps plan delivery windows, rooftop access, and safety. Many pallets carry 30–60 large pavers, but packaging varies by thickness and material. If a crane, hoist, or service elevator is required, staging space becomes a critical constraint. Use the pallet estimate to coordinate lift schedules and avoid leaving heavy loads concentrated in one zone. Spread stock across beams when allowed.
Cost Modeling for Better Decisions
Cost estimates combine paver pricing, labor per area, delivery, and optional tax. Because rooftop work is access-sensitive, labor can swing widely with stairs, lifts, and cut density. Run at least two scenarios: a conservative waste rate and a high-complexity layout. The CSV and PDF exports support sharing with suppliers, installers, and design stakeholders. Track quotes by paver type to compare value.
FAQs
How does the joint gap change the paver quantity?
The calculator uses a module of paver size plus gap in both directions. Larger gaps increase module area and can reduce the paver count slightly. Keep gaps realistic to match spacers, drainage, and layout tolerances.
Should I include pedestals, mats, or drainage layers in weight?
Yes. The weight estimate focuses on pavers, so add any pedestal system, protection mat, insulation cover, and furniture. If you do not know those weights yet, use a conservative limit and verify with project documentation.
What waste percentage is reasonable for rooftop projects?
Many straight layouts work with 5–8% waste. Rooftops with planters, corners, and step-backs often need 8–12%. Diagonal patterns or frequent cuts may exceed 12%. Keep a few spare pavers for future repairs.
Can I calculate using mixed paver sizes or patterns?
This tool assumes a single paver size for the module calculation. For mixed sizes, run separate scenarios by zone, then combine totals. Add extra waste to cover transitions, borders, and pattern alignment across different modules.
How do I use the load limit field safely?
Enter a target dead-load limit from approved drawings or an engineer’s guidance. Compare the calculated load per area to that limit, then consider other permanent loads and live loads. When in doubt, treat the result as a planning flag, not approval.
Why do “full pavers” and “cut pieces” look approximate?
They are estimates derived from the base count and allowances. Actual cut requirements depend on edge conditions, pattern direction, and obstacle placement. Use the total paver count for ordering, then confirm the layout with a drawing or dry-fit plan.
Example Data Table
| Scenario | Deck size | Paver size | Gap | Waste | Estimated pavers | Estimated pallets |
|---|---|---|---|---|---|---|
| Small terrace | 12 × 10 ft | 24 × 24 in | 0.25 in | 6% | ≈ 27 | ≈ 1 |
| Wraparound planters | 22 × 14 ft | 24 × 24 in | 0.25 in | 10% | ≈ 67 | ≈ 2 |
| Compact metric deck | 6 × 4 m | 600 × 600 mm | 6 mm | 7% | ≈ 74 | ≈ 2 |
| Diagonal layout | 18 × 14 ft | 16 × 16 in | 0.25 in | 12% | ≈ 143 | ≈ 4 |