DeckingPro™ DS50 Decking Screw Technical Specification
Dimensions, Installation & Compatibility for the DeckingPro™ DS50 Decking Screw
DeckingPro™ DS50 is a 4.5 x 50mm double countersunk A2 stainless steel decking screw engineered for face-fixing composite and timber decking boards, fascia boards, riser boards and timber decking to softwood, hardwood and corrosive timber subframes. See the full range of screws on the DeckingPro™ DS50 decking screws page.
The double countersunk head reduces the risk of head shear and assists completion of countersinking, allowing the fixing to sit flush below the board surface. The helix shank removes debris during installation and improves clamping performance. The single slash point reduces drive torque and minimises the risk of timber splitting at low edge distances - particularly important when fixing boards close to their ends and edges.
DeckingPro™ DS50 screws are powder coated in-house at RALfixings to precise RAL colour specifications, with the electrostatic coating applied to the screw head only. This preserves the full mechanical performance and corrosion resistance of the A2-304 stainless steel base screw while delivering a durable, colourfast head finish that blends with the board surface. Available in 8 RAL colour-matched finishes matched to leading UK decking board colours.
DeckingPro™ DS50 screws are specified by landscape contractors, decking installers, and outdoor fit-out teams for face-fixing decking boards where hidden clip systems are not appropriate - including fascia boards, stair risers, step treads, perimeter framing and replacement board installation.
Technical specification
| Size (mm) | 4.5 x 50mm |
| Size (imperial) | 9 x 2 |
| Thread Diameter | 4.5mm |
| Head Diameter | 8.76mm |
| Head Type | Double Countersunk with Ribs |
| Recess Type | Pozi PZ2 |
| Thread Type | 40° Single Deep |
| Thread Coverage | Partially threaded - 50mm |
| Shank Type | Helix |
| Point Type | 25° Sharp with Single Slash |
| Gauge | 9 |
| Material | Austenitic Stainless Steel (A2-304) |
| Head Finish | Powder coated - RAL colour to order (head only) |
| Corrosion Rating | 4 - Urban & industrial areas with a moderate salt atmosphere |
| CE Standard | BS EN 14592:2008 (base screw) |
Key design features
- Double countersunk head with ribs - reduces the likelihood of head shear and assists completion of countersinking, allowing the fixing to sit flush below the board surface for a clean, near-invisible finish
- Helix shank - removes debris during installation and improves clamping force between the board and the subframe
- Single slash point - reduces drive torque and minimises the risk of timber splitting when fixing at low edge distances, such as board ends and perimeter fixings
- A2-304 stainless steel - provides strong corrosion resistance for standard UK outdoor environments including decking platforms, balconies and terraces
- Powder coated head (head only) - electrostatic process produces a durable, UV-resistant colour finish matched to the board surface; coating applied to the head only, preserving full mechanical integrity of the stainless steel thread and shank
Intended applications
DeckingPro™ DS50 screws are designed for face-fixing applications in decking installations where a colour-matched fixing is required and hidden clip systems are not suitable.
- Composite decking boards - face fix to timber or steel subframes
- Fascia boards and perimeter decking edges
- Riser boards and decking stair strings
- Stair treads and step fixings
- Softwood and hardwood timber decking boards
- Decking repairs and replacement board installation
- Balcony and terrace decking where clip systems cannot be used
- Commercial outdoor decking platforms and walkways
Substrate compatibility
DeckingPro™ DS50 is suitable for use with composite and timber decking boards fixed to a range of subframe materials. A2 stainless steel is required where fixing into corrosive timber species.
- Composite decking boards - all standard UK hollow and solid composite board profiles
- Softwood joists and subframes - treated and untreated softwood timber (C16, C24)
- Hardwood joists and subframes - including oak, iroko, and hardwood decking frameworks
- Corrosive timber species - green oak, cedar, sweet chestnut, and other tannin-rich timbers where stainless steel is required to prevent staining and chemical corrosion of the fixing
- Softwood and hardwood decking boards - suitable for face-fixing solid timber decking in matching or contrasting RAL colour finishes
- Steel decking subframes - pre-drilling recommended for light gauge steel framing
Installation guidance
- Use a variable-speed cordless or mains driver with a PZ2 bit
- Set clutch to avoid overdriving - the double countersunk head should sit flush with or just below the board surface
- Pre-drilling is not required in most standard decking board and softwood joist applications
- For hardwood joists or fixings within 15mm of board edges, a 3.5mm pilot hole is recommended to prevent splitting
- Recommended fixing centres: 300–400mm per board
- Minimum edge distance: 15mm from board edge
- Minimum end distance: 25mm from board end
- Ensure decking subframe is level, structurally adequate and correctly spaced before installation
- Do not use with incompatible coating systems or preservatives that may react with stainless steel
Corrosion & durability
DeckingPro™ DS50 is manufactured from A2-304 austenitic stainless steel, providing strong corrosion resistance suitable for standard UK outdoor decking environments. The powder coated head provides an additional protective layer at the exposed fixing face.
- A2-304 stainless steel core - corrosion resistant throughout the full shank and thread
- Corrosion rating 4 - suitable for urban and industrial environments with moderate salt atmosphere
- Powder coated head - UV-resistant, weather-resistant finish with improved long-term colour retention compared with painted or dip-coated alternatives
- Stainless steel grade ensures compatibility with corrosive timber species including green oak and cedar, where zinc or carbon steel fixings will corrode and stain
- Suitable for standard UK residential and commercial outdoor decking installations
Colour availability
DeckingPro™ DS50 screws are available in 8 RAL colour-matched finishes, each physically matched to the dominant tone of leading UK decking board colours. All 8 colours are stocked for same or next working day dispatch.
- RAL 1015 - Light Ivory
- RAL 1019 - Grey Beige
- RAL 7009 - Green Grey
- RAL 7016 - Anthracite Grey
- RAL 7035 - Light Grey
- RAL 7042 - Traffic Grey A
- RAL 8019 - Grey Brown
- RAL 8028 - Terra Brown
For colour matching guidance see the DeckingPro™ colour matching guide.
Packaging & supply
DeckingPro™ DS50 screws are supplied in the following retail pack sizes:
- 25
- 50
- 100
- 200
- 500
Trade account holders can access the following volume pack sizes at trade pricing:
- 200
- 500
- 1,000
- 2,000
Each pack is labelled by RAL colour code and product reference.
Suggested specification wording
Fixings for decking boards shall be DeckingPro™ DS50 Colour-Matched Decking Screws, 4.5 x 50mm, double countersunk with ribs, helix shank, single slash point, A2-304 austenitic stainless steel, powder coated head in RAL [colour code] to match decking board. Minimum fixing centres 300mm. Supplied by RALfixings Ltd, Pro Colour Group Ltd.
Technical support
DeckingPro™ is a colour-matched decking fixing system supplied by RALfixings Ltd. Trade, project and specification support is available including:
- Project quantity calculations
- Colour matching guidance against specific board brands and colourways
- Stock colour availability confirmation
- Trade account pricing
- Specification assistance for landscape and outdoor construction projects
For technical support or specification assistance please contact info@ralfixings.com.