Home » Blog » A Complete Guide to Decking FoundationsA Complete Guide to Decking Foundations by Sam Jeans20 January 2025Share: Decking foundation options explainedDecking 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 DeckFor 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 levelMixing and pouring concrete accuratelyInstalling post supports once curedAdding damp-proof membranesCareful backfilling around completed postsWhile 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 FoundationsGround 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 WorkGround 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 DeckBrackets form the link between ground screws and your decking structure. Our bracket range includes:Standard bracket systems for simple joist connectionsDouble joist brackets for extra supportSquare top brackets for larger loadsU-brackets for post mountingSIPS panel support brackets for modern buildsBrackets 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. Your decking is connected to the top of the ground screws.Where Ground Screws Work Best: Ideal ApplicationsGround 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 ProjectsFor 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 FeaturesDecking 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.Decking areas sometimes need to be able to handle heavy fixtures, such as outdoor kitchens or BBQs.Managing Difficult Ground ConditionsSloping 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.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 FeaturesWorking 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).This wrap-around decking would have been very challenging to build on a concrete base.Installing Your Ground Screws: A Guide to Getting StartedGround 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 screwUsing specialised equipment to drive screws to exact depthsChecking and adjusting levels throughout installationFinal quality inspection of all fixing pointsMost installations are completed within a single day, so you can start building your deck more or less immediately.Ground Screw Centre’s install team can handle projects of any scale and complexity.Taking the DIY ApproachMany 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 guidesTechnical support throughout your projectAll necessary brackets, fixings, and toolsTrial kits to test the systemRapid delivery on all componentsBefore starting DIY installation, you’ll need:Ground screw installation tools (available for purchase or rental)Standard measuring equipmentSpirit level and string linesBasic hand tools for bracketsSite plan showing screw positionsWe 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 FoundationsGround 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. 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 needExplore our DIY supply options with next-day deliveryBook a professional installation assessmentContact our team for expert advice on your projectWant 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.