When selecting a polycarbonate roofing sheet for commercial, industrial, or institutional projects, one of the most common technical decisions is:
Should you use 12mm multicell polycarbonate or 16mm multicellpolycarbonate?
For architects, structural consultants, roofing contractors, and fabricators, the choice impacts:
U-value (thermal insulation)
Load-bearing capacity
Purlin spacing
Light transmission
Project cost per sq.ft
Compliance with government specifications
This guide compares 12mm vs 16mm multicell polycarbonate sheets based on structural performance, thermal properties, and real-world applications.
What is Multicell Polycarbonate?
Multicell polycarbonate sheets are hollow structured panels with multiple internal walls that:
Improve thermal insulation (low U-value)
Increase impact resistance
Reduce sheet weight compared to solid panels
Allow diffused natural daylight
They are widely used for:
Skylights
Railway platforms
Airport canopies
Commercial façades
Warehouse daylight panels
Technical Comparison: 12mm vs 16mm Multicell Polycarbonate
| Parameter | 12mm Multicell | 16mm Multicell |
|---|---|---|
| Thickness | 12 mm | 16 mm |
| U-Value | ~1.8–2.1 W/m²K | ~1.4–1.6 W/m²K |
| Thermal Insulation | Good | Excellent |
| Purlin Spacing | Moderate | Wider span possible |
| Load Bearing | Medium | High |
| Impact Resistance | High | Very High |
| Cost per Sqft | Lower | Higher |
| Best Use | Commercial roofing | Industrial / large span roofing |
1. Thermal Performance & U-Value Comparison
Thermal performance is one of the most important factors in roofing design.
The U-value indicates how much heat passes through the sheet.
Lower U-value = Better insulation.
Detailed Thermal Performance Table
| Thermal Parameter | 12mm Multicell | 16mm Multicell | Technical Impact |
|---|---|---|---|
| U-Value | 1.8 – 2.1 W/m²K | 1.4 – 1.6 W/m²K | Lower is better |
| Heat Gain Reduction | Moderate | High | Reduces indoor heat |
| HVAC Load Reduction | Medium | Significant | Saves energy |
| Suitable for Hot Indian Climate | Yes | Highly Recommended | |
| ECBC Compliance | Conditional | Easier to Achieve | |
| Thermal Comfort in Warehouses | Moderate | Improved |
Why 16mm Performs Better Thermally
Thicker internal air chambers
Increased insulation barrier
Reduced heat transfer
Better energy efficiency
For factories running 10–12 hours daily, this difference can significantly impact electricity bills.
If your project targets:
ECBC compliance
LEED certification
Energy-efficient building envelope
Reduced HVAC cost
16mm multicell polycarbonate is the safer technical choice.
2. Structural Strength & Span Capability
Structural consultants often evaluate:
Maximum purlin spacing
Wind load resistance
Deflection limits
Long-term durability
Structural Comparison Table
| Structural Parameter | 12mm | 16mm |
|---|---|---|
| Rigidity | Moderate | Higher |
| Span Capability | Standard | Wider |
| Wind Load Resistance | Good | Better |
| Suitable for Large Sheds | Limited | Recommended |
| Industrial Roofing | Yes | Highly Suitable |
Practical Example
For large warehouses:
12mm may require closer purlin spacing
16mm allows wider spacing
This reduces structural steel consumption
In some projects, 16mm may offset its higher material cost through structural optimization.
3. Daylighting Performance
One major advantage of multicell polycarbonate is natural daylight integration.
Both 12mm and 16mm sheets provide:
35%–60% light transmission
Diffused glare-free illumination
Reduced artificial lighting during daytime
Key Difference
12mm allows slightly more light transmission
16mm balances daylight with insulation
For industrial roofing where glare control and heat reduction are both important, 16mm offers better balance.
4. Cost Comparison – Short-Term vs Long-Term Value
Contractors often focus on sheet price per sq.ft.
Cost vs Performance Table
| Cost Factor | 12mm | 16mm |
|---|---|---|
| Initial Cost | Lower | Higher |
| Installation | Slightly Lower | Slightly Higher |
| Energy Savings | Moderate | Higher |
| Lifecycle ROI | Good | Excellent |
If the project is:
Budget-sensitive
Small commercial building
Temporary structure
12mm works well.
If the project is:
Industrial shed
Factory
Warehouse
Infrastructure project
16mm delivers better lifecycle performance.
5. Application-Based Selection Guide
| Project Type | Recommended Thickness |
|---|---|
| Commercial Complex Roofing | 12mm |
| Retail Shed | 12mm |
| School Skylight | 12mm |
| Warehouse Roofing | 16mm |
| Factory Shed | 16mm |
| Railway Platform | 16mm |
| Airport Canopy | 16mm |
| ECBC / Green Building | 16mm |
6. Climate-Based Recommendation
India has varied climate zones:
Hot-dry
Composite
Coastal
Cold
In hot industrial zones like:
Rajasthan
Gujarat
Maharashtra industrial belts
16mm multicell significantly reduces internal temperature gain.
In moderate climate regions:
12mm can perform adequately.
Which One Should Architects Specify?
Architects should consider:
Building envelope performance Thermal comfort Structural span Energy codes Budget constraints
If performance and long-term efficiency are priority → 16mm
If cost control and moderate performance are sufficient → 12mm
Final Verdict: 12mm vs 16mm – The Smart Selection
There is no universal answer.
The decision depends on:
Project type
Span requirement
Thermal target
Budget
Compliance needs
But in modern industrial roofing and infrastructure projects, 16mm multicell polycarbonate is increasingly becoming the preferred specification.
For commercial and mid-size roofing projects, 12mm remains a cost-effective solution.
Need Help Selecting the Right Thickness for Your Project?
Choosing between 12mm and 16mm multicell polycarbonate depends on span design, climate zone, insulation requirements, and budget.
Our technical team can help you:
Compare U-value and thermal performance
Optimize purlin spacing
Evaluate wind load requirements
Select sheet thickness based on ECBC / project specifications
Estimate cost per sq.ft for your roofing system
Speak to Our Technical Expert Today
or
Request a Project-Specific Recommendation
