A Complete Guide to Decking Foundations

decking foundations

Decking foundation options explained

Decking areas are some of the best additions you can make to your home. They’re perfect for barbecues and hot tubs, give you somewhere to sit and enjoy the garden, and provide a solid platform for outdoor furniture and features.

Your choice of foundations is the first and most crucial decision for any deck project. It affects how quickly you can build, how level it is, and its durability and longevity. 

Choosing decking foundations used to be simple – most just used concrete. But with modern options like ground screws now available, it’s worth understanding the full extent of the options available today. 

Read on to explore the different options available for decking foundations, with expert build tips and best practices for success. 

Understanding Available Foundation Options for Your Deck

For many years, concrete post foundations have been the default choice for deck construction. 

This tried-and-tested method still has its place today, though it’s worth understanding exactly what’s involved before you commit:

  • Extensive digging to reach below frost level
  • Mixing and pouring concrete accurately
  • Installing post supports once cured
  • Adding damp-proof membranes
  • Careful backfilling around completed posts

While concrete foundation methods provide solid support, they present several challenges that are too often overlooked. Primarily, negotiating slopes, plant roots, or trees can be difficult or impossible. If your garden is extremely wet or damp, or you’re building near water, that can complicate the process further. 

Additionally, concrete is far from the most eco-friendly or sustainable construction material, accounting for a sizable portion of carbon emissions worldwide. Ground screws offer a convenient, cost-effective solution to these drawbacks while offering many unique features that benefit decking installations. 

Modern Ground Screw Foundations

Ground screws have been around for decades, but they’re now becoming the go-to choice for decking foundations. 

They combine remarkable strength with rapid installation, challenging traditional concrete bases in both performance and practicality.

We’ll next explore ground screws in detail, diving into exactly why they’re an excellent choice for your decking foundation. 

Ground screws offer a compelling alternative to concrete, especially for decking areas.

How Ground Screws Work

Ground screws are an innovative foundation solution designed to provide strength and stability without the need for extensive excavation or concrete. 

They’re built from a precision-engineered steel shaft with specially designed helical plates attached.

These plates serve two key purposes: they help drive the screw into the ground, and they create powerful anchoring points that resist both downward pressure and lateral movement. 

Every ground screw from the Ground Screw Centre (GSC) is hot-dip galvanised to protect against rust and corrosion – that’s why we can confidently offer a 20-year guarantee.

Connecting Your Deck

Brackets form the link between ground screws and your decking structure. Our bracket range includes:

  • Standard bracket systems for simple joist connections
  • Double joist brackets for extra support
  • Square top brackets for larger loads
  • U-brackets for post mounting
  • SIPS panel support brackets for modern builds

Brackets allow for precise height adjustment even after installation, ensuring your deck stays perfectly level regardless of ground conditions. 

Once complete, the system can handle impressive loads, providing reliable support for modern decking installations. 

ground screw foundation
Your decking is connected to the top of the ground screws.

Where Ground Screws Work Best: Ideal Applications

Ground screws offer unmatched versatility and ease of installation, making them suitable for a wide range of decking projects, from simple garden platforms to complex multi-level designs.

Here’s a closer look at the many projects that suit ground screw foundations:

Standard Decking Projects

For standard garden decking projects, ground screws provide quick installation and perfect levelling. 

Adjustable brackets systems mean you can create precise supporting frameworks for any decking material, whether you’re using traditional timber, composite boards or modern PVC systems.

Supporting Heavy Features

Decking platforms designed to support heavy loads, such as hot tubs or outdoor kitchens, present challenges that ground screws handle well. 

The concentrated weight of a filled hot tub demands reliable support – ground screws provide immediate load-bearing capability without the wait times associated with concrete. 

Precise height adjustment helps ensure your hot tub sits perfectly level, which is essential for proper operation.

ground screw decking area
Decking areas sometimes need to be able to handle heavy fixtures, such as outdoor kitchens or BBQs.

Managing Difficult Ground Conditions

Sloping or uneven ground often renders concrete bases extremely hard to lay. The sames goes for laying decking near water, where concrete may not be viable at all. Ground screws offer a pragmatic solution. 

The ability to install screws at different heights while maintaining solid anchoring means you can create level decking without extensive groundwork. This saves both time and money while preserving your garden.

decking foundations
Ground screws are ideal for laying decking near or above water, as they can penetrate deep into the soil below the water line.

Working Around Garden Features

Working around trees is much simpler when you use ground screws. Unlike concrete foundations, which can damage root systems, ground screws thread between roots without causing harm – ideal for projects in mature gardens where preserving trees is important. 

This also may be required by law (e.g. in the case of a Tree Preservation Order).

ground screw foundations.
This wrap-around decking would have been very challenging to build on a concrete base.

Installing Your Ground Screws: A Guide to Getting Started

Ground screws are remarkably similar compared to traditional foundations, but proper installation is still vital. 

Here are some best practices for nailing your decking project, whether you plan on professional help or are keen to go DIY:

Professional Installation 

Professional installation guarantees the best possible outcome. GSC’s nationwide domestic and commercial installation teams bring over 15 years of experience to every project, ensuring your ground screws are sturdy and perfectly level and ready to handle your decking. 

Our team conducts a thorough site survey, checking ground conditions and identifying any underground services. They’ll assess soil type, measure levels, and plan the optimal position for each ground screw to support your deck design.

Installation day involves:

  • Marking out precise locations for each ground screw
  • Using specialised equipment to drive screws to exact depths
  • Checking and adjusting levels throughout installation
  • Final quality inspection of all fixing points

Most installations are completed within a single day, so you can start building your deck more or less immediately.

GSC installation
Ground Screw Centre’s install team can handle projects of any scale and complexity.

Taking the DIY Approach

Many homeowners successfully install their own ground screws, saving money while maintaining complete control over their projects. 

Our DIY supply service provides everything needed for successful installation:

  • Comprehensive installation guides
  • Technical support throughout your project
  • All necessary brackets, fixings, and tools
  • Trial kits to test the system
  • Rapid delivery on all components

Before starting DIY installation, you’ll need:

  • Ground screw installation tools (available for purchase or rental)
  • Standard measuring equipment
  • Spirit level and string lines
  • Basic hand tools for brackets
  • Site plan showing screw positions

We recommend starting with our trial kit, which lets you test the installation process and ensure ground screws suit your site conditions before committing to the full project.

The Benefits of Ground Screw Foundations

Ground screws offer a range of benefits that make them an excellent choice for decking projects, whether for a small garden or a larger commercial installation. They’re practical, reliable, and designed to outlast a traditional concrete or timber solution. 

One of the greatest advantages is their long-term stability. Unlike concrete, which can crack or shift over time, ground screws are built to stay secure, even as the ground settles or conditions change.

They’re also incredibly adaptable, which is especially useful if your needs evolve. For example, ground screws can be:

  • Adjusted: Easily raised or lowered if ground levels change.
  • Removed: Taken out completely if you decide to move the structure.
  • Reused: Relocated to a new site for a different project.
  • Modified: Adapted to support new structures as your space evolves.

On top of that, ground screws are much kinder to the environment compared to traditional concrete. They don’t require heavy excavation or soil removal, there’s no concrete involved, and they minimise disruption to the ground. 

Thus, they’re perfect for protecting tree roots, gardens, or other natural features. Plus, they leave no permanent impact behind when removed. 

decking
A complete decking laid on top of ground screw foundations. View the case study.

Ready to Start Your Decking Project?

GSC is the UK’s leading ground screw specialist. We’ve helped thousands of homeowners create perfect foundations for their decking projects. 

We maintain one of the country’s largest stocks of ground screws and accessories, offering next-day delivery nationwide. We also provide expert support throughout your project, providing everything you need for a successful installation.

Take the first step towards your new deck with Ground Screw Centre:

  • Try our Ground Screw Calculator to work out exactly what you need
  • Explore our DIY supply options with next-day delivery
  • Book a professional installation assessment
  • Contact our team for expert advice on your project

Want to learn more? View our range of ground screws and brackets, check out our case studies showing ground screws in action, or contact us for help and support.