Road Form Pins: A Complete Buying Guide for Construction & Site Work
Introduction
Road form pins are one of the most-used products on any construction site — and one of the least thought about. They anchor temporary fencing, secure road forms and shuttering, mark survey lines, and pin ground sheets and erosion matting. Get the size wrong and the pin won't hold; get it right and it disappears into the ground without a second thought.
This guide by Cocus covers everything you need to know about choosing the right steel road form pins — diameter, length, quantity, and when to add safety caps — so you can order with confidence and get on with the job.
1. 12mm Road Form Pins — Lightweight Survey & Marking
The 12mm pin is the slimmer, lighter option — ideal for survey marking, temporary line pins, and applications where the pin is being used as a visual marker rather than a structural anchor. Easier to drive by hand and easier to remove, making them popular with surveyors, groundworkers doing layout work, and contractors who need quick temporary markers across a site.
12mm x 450mm Steel Road Form Pins
High-grade steel pins, 12mm in diameter and 450mm long. Sold individually at £1.87 or in a 10-pack at £17.50. The go-to choice for survey pegging, temporary line marking, and any application where the pin needs to be driven and removed quickly. Manufactured from robust steel for durability on site.
2. 16mm Standard Pins — Temporary Fencing & Road Forms
The 16mm diameter pin is the industry standard for temporary fencing (including Heras-style panel fencing), road form shuttering, and general ground anchoring across construction sites. The larger diameter provides significantly more holding strength than 12mm pins, making them suitable where the anchor needs to resist lateral load — for example, along the base of a temporary fence line.
16mm x 450mm Steel Road Form Pins
The standard workhorse pin for most temporary fencing applications. At 450mm, suitable for firm, compacted ground where the fence line is relatively sheltered. Single pins from £3.54; 10-packs from £28.20. If you're unsure which length to order, the 450mm is the most common starting point.
16mm x 600mm Steel Road Form Pins
The 600mm pin gives an additional 150mm of ground penetration over the 450mm — useful in slightly looser or sandy ground, or where the fence line is more exposed. Single pins from £3.22; 10-packs from £29.40.
3. 16mm Heavy Duty Long Pins — Hard Ground & Deep Anchoring
Where ground conditions are challenging — clay-heavy soil, compacted hardcore, or sites exposed to wind load — longer pins provide the extra penetration depth needed to keep temporary structures secure. These are also the correct choice for road form work where the shuttering needs to resist the pressure of wet concrete.
16mm x 900mm Steel Road Form Pins
900mm pins are the standard choice for road form shuttering and for temporary fencing in exposed locations or softer ground. Single pins from £4.55; 10-packs from £42.70.
16mm x 1200mm Steel Road Form Pins
The longest pin in the range at 1200mm — used where maximum ground penetration is required, such as on sloping ground, near watercourses, or in ground that has been disturbed and backfilled. Single pins from £7.80; 10-packs from £77.40.
4. Road Pin & Rebar Protection Caps
Any protruding ground pin or rebar is a safety hazard. HSE guidance is clear: exposed steel stakes must be capped to prevent eye and facial injuries on site. Road pin protection caps are a legal compliance requirement, not an optional extra.
Rebar & Road Pin Protection Caps
High-visibility "mushroom" caps designed to fit securely over protruding road pins and rebar. Available in two sizes: 8mm–16mm (covering the full road form pin range) and 16mm–32mm for larger rebar. Sold in packs of 1, 5, 10, 25, and 50 — from £0.60 each. Order one per pin as a matter of course.
5. How to Choose the Right Road Form Pin
The two variables that matter are diameter and length. Here's how to make the right call on both:
1. Diameter: 12mm or 16mm?
Use 12mm pins for survey pegging, temporary line marking, and light-duty applications where the pin won't be subject to lateral load. Use 16mm pins for everything else — temporary fencing, road form shuttering, ground anchoring, and any application where the pin needs to resist movement. The 16mm pin has significantly greater holding strength and is the construction industry standard for structural anchoring.
2. Length: Which Size for Your Ground Conditions?
In firm, compacted ground, 450mm is usually sufficient. In softer ground (clay, sand, disturbed backfill) or where the pin will be subject to more load, go to 600mm or 900mm. For road form shuttering against wet concrete pressure, or for exposed temporary fencing on open sites, 900mm is the standard. Use 1200mm pins only where maximum penetration is needed — sloping ground, near watercourses, or in loose fill.
3. How Many Pins Do You Need?
For temporary panel fencing, pins are typically used at every foot of each panel — so a 3.5m Heras panel needs approximately 4 pins across its base. For a 100m fence run, that's roughly 120–140 pins. It's worth ordering 10–15% more than you calculate — pins bend, get lost, and stay in the ground at the end of a job.
4. Don't Forget Safety Caps
Order protection caps alongside every order of pins. HSE requires all exposed ground pins to be capped at all times on site. Caps are inexpensive and the compliance risk of not using them is not worth it.
6. Road Form Pins Frequently Asked Questions
Q1: What diameter road form pin do I need for temporary Heras fencing?
16mm pins are the standard for Heras and other panel-style temporary fencing. The 12mm pin doesn't provide enough lateral holding strength for fence panels subject to wind load or pedestrian contact. For most sites, 16mm x 450mm or 16mm x 600mm pins are the correct choice; use 900mm pins on more exposed sites or in softer ground.
Q2: What's the difference between a road form pin and a survey pin?
The terms are sometimes used interchangeably, but in practice survey pins (also called marker pins or line pins) tend to be 12mm or lighter gauge and are used for temporary marking — they're not intended to carry structural load. Road form pins (16mm) are heavier gauge and are designed to anchor shuttering and fencing against lateral and vertical forces.
Q3: How deep should a road form pin be driven?
As a general rule, at least two-thirds of the pin should be below ground level. For a 450mm pin, that means a minimum of 300mm penetration. If you're finding pins too shallow after driving, move to the next length up rather than leaving more of the pin exposed above ground.
Q4: Are road form pins a legal requirement on construction sites?
The pins themselves aren't mandated by law, but the requirement to secure temporary fencing and formwork is. Under the Construction (Design and Management) Regulations 2015, temporary structures must be adequately supported and secured. Road form pins are the standard method of achieving this compliance for ground-level applications.
Q5: Do I need to cap road form pins on site?
Yes. HSE guidance requires that protruding metal stakes are capped to prevent impalement injuries. This applies to road form pins left partially exposed above ground at any time on site. High-visibility protection caps are the standard solution and cost from £0.60 each.
Q6: Can I buy road form pins in bulk from Cocus?
Yes — we stock road form pins in single and 10-pack quantities, across all diameters and lengths, available for next-day delivery from our Manchester warehouse. Contact us at info@cocus.co.uk if you need a larger volume quote.
Conclusion
For most temporary fencing and road form applications, a 16mm pin is the right choice — with length determined by ground conditions and the load the pin needs to resist. When in doubt, go longer: a pin driven to depth will always outperform a pin that's too short, and the cost difference between lengths is minimal compared to the cost of a fence line that fails. Don't forget to cap every pin that protrudes above ground — it's a site safety requirement, not a suggestion.
Browse our full range of road form pins and ground anchoring accessories at Cocus, including construction site equipment shipped from our Manchester warehouse with next-day delivery available on selected products.