Composite Decking Boards
Sylvan composite decking boards come in three colours and two strengths: a lightweight hollow-core board for gardens and a solid-core board for commercial and high-footfall areas. Both are 150 x 25 x 4000mm, tested to BS EN 15534 and fixed with hidden clips for a screw-free surface.
What are Sylvan composite decking boards made of?
Sylvan boards are a wood-polymer composite, often shortened to WPC. Recycled plastic and wood fibre are blended with additives and extruded into a sealed board that keeps water out and holds its shape.
30%
Recycled HDPE
Grade A recycled high-density polyethylene
60%
Wood fibre
Reclaimed wood fibre for a natural look and feel
10%
Additives
Anti-UV agent, antioxidant, stabiliser, colourant and lubricant
Composite decking colours: Anthracite, Silver and Coffee
Each colour is available in both board profiles, so you can pick the look you want and then the strength the job needs.
Anthracite
A deep charcoal grey for a crisp, modern look
Silver
A light, cool grey that lifts a shady garden
Coffee
A warm mid brown, closest to traditional timber
Composite is made in batches, so a slight variation in shade can occur between production runs and one order may contain boards from more than one batch.
Hollow core or solid core composite decking?
For most gardens, the hollow-core board does the job at a lower cost. Choose solid core where the deck will take heavy use, point loads or longer joist spans.
3D Embossed Hollow Core
1520N
Maximum load (EN 15534-1)
The lighter, cost-effective choice for back gardens, raised platforms and poolside areas.
- 150 x 25 x 4000mm
- 2.83kg per metre
- Water absorption 2.8%
- Takes end caps for a neat finish
Solid Core
2550N
Maximum load, 68% higher than hollow core
A denser board for commercial, retail and public realm schemes, built for longer joist spans and better point-load resistance.
- 150 x 25 x 4000mm
- 4.92kg per metre
- Water absorption 1.2%
- Stiffer, with a modulus of elasticity of 5880 MPa
What every Sylvan board has
Both profiles share the same surface and fixing details, so a hollow-core garden deck and a solid-core commercial deck look and fit the same way.
- 3D wood-grain embossing for a natural timber texture and better grip
- A co-extruded protective shield for extra resistance to fading, staining and scratches
- A grooved fixing channel on both edges for hidden clips
- A sealed profile that resists water getting in and cyclic moisture damage
- No sanding, staining or oiling, ever
- Tested to BS EN 15534 and rated Bfl-s1 for reaction to fire
Composite decking technical data
Here are the full test results for both boards, so you can compare like for like. Technical data sheets are available on request.
| Characteristic | Test method | Hollow core | Solid core |
|---|---|---|---|
| Board size | 150 x 25 x 4000mm | 150 x 25 x 4000mm | |
| Weight | 2.83kg/m | 4.92kg/m | |
| Maximum load | EN 15534-1:2014+A1:2017 | 1520N | 2550N |
| Modulus of elasticity | ASTM D7032-17 | 3880 MPa | 5880 MPa |
| Modulus of rupture | ASTM D7032-17 | 33 MPa | 42.3 MPa |
| Density | ASTM D792-13, Method A | 1.35 g/cm³ | 1.35 g/cm³ |
| Resistance to indentation | ASTM D4812-19 | 0.55 | 0.35 |
| Water absorption | ASTM D7031-11 (2019) | 2.8% | 1.2% |
| Linear thermal expansion | ASTM D7031-11 (2019) | 55 x 10⁻⁶ K⁻¹ | 36.1 x 10⁻⁶ K⁻¹ |
| Moisture resistance (cyclic) | EN 15534-4:2014 | Pass | Pass |
| Falling mass impact resistance | EN 15534-4:2014 | Pass | Pass |
| Reaction to fire | EN 13501-1 | Bfl-s1 | Bfl-s1 |
| Slip resistance (wet and dry) | ASTM D7032-17, Section 5.6 | 0.26 to 0.65 | 0.48 to 0.65 |
Slip resistance was tested wet and dry, longitudinally and horizontally, under ASTM D7032-17, Section 5.6.
Living with composite decking
All Sylvan decking is manufactured and quality tested to BS EN standards. Like any composite, it is a natural blend, so expect a slight variation in shade between production batches. Prolonged sun can cause gradual fading, and changes in heat and moisture can cause minor movement.
None of this is a defect. It does not affect structural performance or lifespan when the deck is installed and maintained in line with the fitting guidelines.
Composite decking board questions
What is the difference between hollow and solid core decking?
Hollow-core boards are lighter and more cost-effective, and suit most residential gardens. Solid-core boards are denser and take a 68% higher maximum load (2550N against 1520N), which makes them the choice for commercial, retail and high-footfall areas.
What size are Sylvan decking boards?
Both Sylvan profiles are 150mm wide, 25mm thick and 4000mm long. Hollow-core boards weigh 2.83kg per metre and solid-core boards weigh 4.92kg per metre.
Is Sylvan composite decking slippery when wet?
Sylvan boards have been slip tested wet and dry under ASTM D7032-17, Section 5.6. Results range from 0.26 to 0.65 for the hollow-core board and 0.48 to 0.65 for the solid-core board, and every board has a 3D wood-grain embossed surface for grip.
Will composite decking fade?
Every Sylvan board has a co-extruded shield layer to resist fading, but long spells of strong sun can cause gradual fading over time. This is normal for composite decking and does not affect its strength or lifespan.
Does composite decking expand?
Yes, composite decking moves slightly with changes in heat and moisture. The linear thermal expansion is 55 x 10⁻⁶ K⁻¹ for the hollow-core board and 36.1 x 10⁻⁶ K⁻¹ for the solid-core board, which is why spacers are used between boards.
Can I get technical data sheets?
Yes. Full technical data sheets for both boards are available on request. Call 01626 333823 or email info@sylvanproducts.co.uk.
More answers on our composite decking FAQs page.
Know which board you want?
Talk to us about composite decking
Phone: 01626 333823 or 01626 332059
Email: info@sylvanproducts.co.uk
Collect from: Unit 21 Olympus Business Park, Kingsteignton Road, Newton Abbot, Devon TQ12 2SN
Sylvan Composite Decking is a brand of Sylvan Property Enterprise Limited.
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