Input Parameters
Calculated Loads
All load results are given per square meter of roof area unless indicated.
| Quantity | Symbol | Value | Unit |
|---|---|---|---|
| Paver dead load | Gp | - | kN/m² |
| Bedding/screed dead load | Gb | - | kN/m² |
| Waterproofing dead load | Gw | - | kN/m² |
| Insulation dead load | Gi | - | kN/m² |
| Additional permanent load | Ga | - | kN/m² |
| Total dead load | Gtotal | - | kN/m² |
| Service load (dead + live) | S | - | kN/m² |
| Design factored load | U | - | kN/m² |
| Total design action on roof area | U × A | - | kN |
Always verify adopted loads and factors against the governing structural design code for your region.
Example Roof Paver Configurations
This example table shows typical combinations of paver, bedding, and insulation thickness and the corresponding approximate dead loads for quick comparison.
| Paver thickness (mm) | Bedding thickness (mm) | Insulation thickness (mm) | Total dead load (kN/m²) |
|---|---|---|---|
| 50 | 30 | 0 | 1.97 |
| 60 | 40 | 50 | 2.65 |
| 80 | 50 | 100 | 3.55 |
Formula used for load calculations
The calculator treats each roof build-up layer as a uniformly distributed surface and converts its self-weight to dead load per square meter of roof area.
The basic relationship between density, thickness, and dead load is:
Dead load (kN/m²) = Density (kg/m³) × Thickness (m) × g (m/s²) ÷ 1000where g is the acceleration due to gravity, taken as 9.81 m/s². Total dead load is the sum of all individual dead loads plus any additional permanent load.
The unfactored service load combines dead and live loads:
Service load S = G_total + Qwhere G_total is the total dead load and Q is the live load in kN/m². The ultimate design load is obtained by applying a load safety factor:
Design load U = S × γfHere, γf represents the load safety factor, which should be selected according to the relevant structural design standard or building code. The total design action on the selected roof area is:
Total factored action = U × Awhere A is the roof area in m², and the result is expressed in kilonewtons.
How to use this calculator
- Enter the concrete roof paver thickness and material density using product data or conservative standard values when manufacturer figures are not available.
- Specify the bedding or screed thickness and density for the layer directly beneath the pavers, such as sand-cement screed or mortar leveling course.
- In the advanced options, add realistic waterproofing and insulation thicknesses, associated densities, and any superimposed permanent loads such as planters, ballast, or rooftop services.
- Input the roof area of interest so that the tool can estimate the overall factored load acting on that area in kilonewtons.
- Choose an appropriate live load and load safety factor according to your governing design standard, occupancy category, and limit state being checked.
- Click “Calculate design load” to generate dead, service, and factored design loads per square meter, plus the total factored action on the selected roof area.
- Use the CSV or PDF download buttons to export the input data and calculated loads for inclusion in design notes, calculation sheets, or review with the wider project team.
This tool is intended as an aid for preliminary sizing and coordination. Final structural design should always be carried out and checked by a qualified engineer.
Roof paver build-up and structural strategy
Concrete roof pavers form only one part of the structural system. This calculator lets you combine paver, bedding, waterproofing, and insulation layers so you can understand how the complete build-up affects roof dead load and design actions.
Using layer loads to check slab capacity
The calculated dead and live loads can be compared against slab capacity, beam design, or deck manufacturer tables. Exported CSV or PDF summaries can be dropped directly into project calculations, sketches, or markups for engineer review and approval.
Coordinating slope design with paver loads
Many flat roofs rely on falls to outlets or gutters. Combine this tool with the Driveway Drainage Slope Calculator to coordinate gradients, ponding checks, and paver build-up weights in a single design workflow.
Allowing for edge beams, upstands, and guardrails
Perimeter details often introduce concentrated loads and extra materials such as edge beams and balustrade posts. Use the additional permanent load field to approximate these effects and document any assumptions clearly in your exported calculation sheets.
Serviceability considerations for paver roofs
While this calculator focuses on loads, deflection and vibration control are also important. Higher dead loads can reduce vibration but may increase long-term deflection. Engineers should balance these effects when finalizing slab thickness or composite deck specifications.
Comparing alternative paver and bedding specifications
Quickly study the impact of different paver thicknesses, densities, or screed depths by re-running the calculation with alternative values. Capture multiple CSV exports to compare lightweight systems versus conventional solutions during value engineering exercises.
Integrating paver loads with pipe support frames
Mechanical and electrical services are often supported on frames sitting above the pavers. Use this tool alongside the Pipe Welding Time Calculator to estimate load effects while coordinating fabrication, erection, and installation durations.
Fastening details and metric threaded components
Edge restraints, pedestals, or service supports may rely on bolted connections. Combine this roof paver load output with the Metric Thread Dimensions Calculator to select appropriate bolt sizes and verify clearances within the roof build-up depth.
Typical workflow when using this roof paver tool
A common sequence is to define the roof build-up, apply relevant live loads, compute design actions, export results, and then check slab or deck capacities in separate structural software or hand calculations, documenting assumptions at each step.
Frequently Asked Questions
What units does this roof paver calculator use?
Inputs and results are based on metric units. Thickness uses millimetres, densities use kilograms per cubic metre, and loads are given in kilonewtons per square metre or total kilonewtons for the selected roof area.
How accurate are the results for structural design?
This tool follows standard engineering relationships for dead and live load combinations. It does not check member strength, punching shear, vibration, or deflection. A qualified structural engineer must review results against the governing code before decisions.
Can I use this calculator for ground paving slabs?
Yes, the underlying physics is similar, but this tool is tuned for flat roof assemblies. For vehicular slabs or exterior hardscape, adjust live loads, material properties, and safety factors and confirm everything using a full structural design package.
How do I choose appropriate live load values?
Begin with the occupancy or access type, then consult your local building code or national standard. Choose the prescribed live load category that matches the roof use and never reduce below the minimum specified value.
How does this differ from a drainage slope calculator?
The Driveway Drainage Slope Calculator focuses on falls and water removal, not structural loads. Use that for drainage layout and this tool for layer weight and design load checks.
Can this help when planning welded support frames?
The Pipe Welding Time Calculator helps plan fabrication and installation durations, not roof loads. Use both together when sequencing prefabricated edge beams, supports, or guardrail posts on paver roofs.