Decking Ground Spike Installation: Step-by-Step Guide
When installing a decking system over soft or uneven terrain, ensuring a stable foundation is essential. Decking ground spikes provide a quick and effective way to stabilise adjustable pedestals without the need for concrete or deep excavation.
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Thu, 28 Jul 2026
This ground spike installation guide explains how to securely install decking pedestals on soft ground, delivering a strong, level and long-lasting base for decking systems.
What Is a Decking Ground Spike?
A decking ground spike is a metal anchor designed to be driven into soft soil to support an adjustable pedestal base. Once in position, it prevents movement and provides a stable, non-slip footing for your decking substructure.
Key benefits:
No concrete required, fast installation with minimal ground disruption.
Strong anchorage for pedestals on soft soil or grass.
Corrosion-resistant design for long-term outdoor performance.
Compatible with adjustable pedestal systems used for decking or paving installations.
Ground spikes are not intended for use as post supports, instead, they act as ground anchors for adjustable pedestals, distributing weight evenly while maintaining level alignment.
Calculating How Many Ground Spikes You Need
The number of ground spikes will be subject to the kind of joists you are using and whether the project is residential or commercial, among other factors.
Building Regulations dictate that
Raised domestic decks, above 600mm from the ground, should be constructed to hold a distributed load of 3.0kN/sqm which is ~300kg per square metre.
Low level decks, under 600mm raised, can be constructed to 1.5kN/sqm (~150kg/sqm), and
Commercial decks should be constructed to 4kN/sqm (~400kg/sqm).
Depending upon the type of ground you will probably require at least 2 spikes per square metre to support decking for a residential project. The limiting factor will normally be the spacing between the joists
Another consideration to the spacing is the size and strength of the joists that you are using.
Ground Spikes in Different Ground Conditions
The figures below show the weight bearing capacity of each MESA ground spike. For each of the three ground conditions, the weights listed are estimates.
Poor Ground Conditions - 150kg
Loose Fine Sand; Alluvium; Soft-Firm Clays; Varied Clays; Fill
Medium Ground Conditions - 200kg
Loose to Medium Dense Fine to Coarse Sand; Firm to Stiff Clays & Silts
Good Ground Conditions - 300kg
Medium Dense Coarse Sand & Sandy Gravel; Stiff to Very Stiff Silts & Clays
How to Install Decking Ground Spikes
Without the requirement for messy dirt removal and digging, the components of the system can be self-installed at an incredible speed with a trench rammer, or at very low cost with a sledge hammer - reducing labour times and the need for adequate site access associated with traditional concrete bases.
The first thing to do is always mark out the area that you are looking to install the decking over. The best way to do this is by positioning your pre-made substructure over the area where you will be installing your deck and then marking the ground spike positions.
Due to the size of the flat head of the ground spike you have some margin for error when originally being placed into the ground.
Remove the pre-made substructure and you are ready to install your ground spikes. From here there are two options for installing:
The Sledgehammer Method
You will need: a sledgehammer.
Wet the area where you are looking to hammer the spike into.
Place a large block of wood (or Manticore plastic lumber) on top of the spike and hit repeatedly with a sledgehammer.
The ground spike can be damaged if the head is struck by a sledgehammer - ensure the block of wood is large (and strong) enough.
Every few strikes look to see whether the spike is still going straight into the ground and adjust.
Note: If a rock is encountered under the spike it might need to be moved slightly.
The Trench Rammer Method
You will need: a trench rammer.
Trench rammers can be hired out at a reasonable daily rate and provide a much faster mechanism for installation.
If you choose to go this route please follow all safety guidelines, use PPE and ensure you are installing the ground spikes as straight as possible.
A Simple, Solid Foundation for Soft Ground
Installing decking ground spikes is a quick and efficient solution for building stable decks on soft or uneven terrain. When combined with adjustable pedestals and a robust joist system, they provide a durable, level foundation for both residential and commercial outdoor spaces.
EnviroBuild offers a range of ground spikes, adjustable pedestals, joists and substructure components, designed to simplify installation and maximise deck stability.
