PVC-U Soffit Boards
Technical Data Sheet
Document Reference: TDS-RF-SO-001
Issue Date: February 2026
Range: PVC-UE Cellular Roofline
Product Description
Kalsi PVC-U soffit boards provide the finishing touch to roofline installations, covering the underside of roof overhangs. Available in solid and ventilated options to suit different ventilation requirements. Manufactured from cellular PVC-UE with co-extruded finish for durability and consistent appearance.
Profile Options
Flat Soffit Boards
| Type | Thickness | Widths Available |
|---|---|---|
| 9mm Solid | 9mm | 100mm, 150mm, 200mm, 225mm, 250mm, 300mm |
| 9mm Vented | 9mm | 100mm, 150mm, 200mm, 225mm, 250mm, 300mm |
Hollow Soffit (Tongue & Groove)
| Type | Thickness | Widths Available |
|---|---|---|
| Hollow Solid | 10mm | 300mm |
| Hollow Vented | 10mm | 300mm |
Physical Dimensions
9mm Flat Soffit
| Width | Thickness | Length | Weight (approx) |
|---|---|---|---|
| 100mm | 9mm | 5m | 2.8 kg |
| 150mm | 9mm | 5m | 4.2 kg |
| 200mm | 9mm | 5m | 5.6 kg |
| 225mm | 9mm | 5m | 6.3 kg |
| 250mm | 9mm | 5m | 7.0 kg |
| 300mm | 9mm | 5m | 8.4 kg |
Hollow Soffit
| Width | Thickness | Length | Weight (approx) |
|---|---|---|---|
| 300mm | 10mm | 5m | 5.0 kg |
Ventilation Performance
Ventilated Soffits
| Product | Ventilation Area |
|---|---|
| 9mm Vented 100mm | [TBC] mm²/m |
| 9mm Vented 150mm | [TBC] mm²/m |
| 9mm Vented 200mm | [TBC] mm²/m |
| 9mm Vented 300mm | [TBC] mm²/m |
| Hollow Vented 300mm | [TBC] mm²/m |
Building Regulations Requirement
For pitched roofs: 25,000mm² continuous ventilation per metre run (or equivalent).
Achieving Adequate Ventilation
| Method | Typical Configuration |
|---|---|
| Full vented soffit | Use vented soffit across full width |
| Partial vented | Solid centre, vented edges |
| Over-fascia vent | Supplement with eaves vent |
Material Specification
| Property | Specification |
|---|---|
| Material | PVC-UE (cellular/foamed) |
| Core structure | Closed-cell foam |
| Outer skin | Co-extruded solid PVC-U |
| UV stabilisation | Yes |
| Fire rating | Class 1 (BS 476) |
Colour Options
| Colour | Stock Availability |
|---|---|
| White | Standard - all sizes |
| Black | Selected sizes |
| Anthracite Grey | Selected sizes |
| Rosewood | Made to order |
| Golden Oak | Made to order |
Installation Requirements
Fixing Method
- Fix to timber bearers or direct to rafters/joists
- Use stainless steel or UPVC-headed screws
- Pre-drill for fixings in cold weather
Fixing Centres
- Maximum 300mm centres across board width
- Bearers at 400-600mm centres
Expansion
- Allow 3mm gap at board ends for thermal expansion
- Use J-section or angles to accommodate movement
Jointing
- Butt joints acceptable for solid soffits
- Use joint covers for cleaner appearance
- Stagger joints for hollow soffit panels
Accessories
Trims
| Description | Application |
|---|---|
| J-Section | Board edges against walls |
| F-Section | Combining with cladding |
| H-Section | Joining boards |
| Starter Trim | First board fixing |
Ventilation Accessories
| Description | Application |
|---|---|
| Over-Fascia Vent | Additional ventilation at eaves |
| Circular Soffit Vent | Spot ventilation |
| Continuous Vent Strip | Eaves ventilation |
Standards Compliance
- ✓ BS EN 12608 - PVC-U profiles
- ✓ BS 476 Part 7 - Fire classification Class 1
- ✓ Building Regulations Part F (ventilation)
- ✓ Lead-free formulation
- ✓ UK manufactured
Guarantee
Product Guarantee: White: 20 years | Coloured: 10 years | Foiled: 10 years
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