1. Introduction
Metal deck and PEB structures require lightweight, UV-stable, reflective, and mechanically fastened waterproofing solutions. Unlike RCC decks, these roofs expand/contract significantly with temperature, and conventional liquid-applied membranes (PU, PVC, cementitious) often fail prematurely due to poor adhesion, UV degradation, or cracking.
2. Key Exposures
- Intense UV & heat cycling → membrane must be UV-stable.
- Wind uplift → requires mechanically fastened or adhered sheets.
- Thermal expansion & vibration of metal decks.
- Water ponding risk if slope is not maintained.
3. Recommended Technologies
Technology | Recommendations | Rationale | Read More |
TPO (Thermoplastic Polyolefin) Membranes | Recommended | High stress on decks, UV Exposure & High Puncture Resistance required |
4. Typical Roof Build-Ups
TPO Single-Ply on Metal Deck
- Metal Deck → Cover Boards [Surface Level] → Vapour Barrier → Thermal Insulation Boards → TPO Sheet (mechanically fastened & seam welded).
5. Performance Benchmarks (TPO)
Property | TPO Membrane | Notes |
UV Resistance | Excellent | Long-term weatherable, reflective |
Tensile Strength | ≥15 MPa | ASTM D412 |
Elongation | ≥250% | ASTM D412 |
Seam Integrity | Weldable seams | Peel & shear tested |
Life Expectancy | 15–20 years | Proven track record |
Thermal Efficiency | High (reflective white surface) | Energy savings for industries |
Decision Guide
- Metal/PEB roof needing exposed, UV-stable system → TPO single-ply with mechanical fastening and weld QA.
- Complex penetrations or aged roof needing overlay without hot works → TPO mechanically fastened; use accessories at details.
- Do not use cementitious or standard PU coatings as primary systems on metal decks due to UV and movement risks.
Video Masterclass
Conix Masterclass: Roof Deck / Metal Deck Waterproofing — Coming Soon
Disclaimer
Conix is an industry initiative & a neutral resource, compiled from industry references and best practices. It is not brand-specific. Always cross-check with project requirements and local codes before finalizing specifications.