Ben Dawson - director

Reviewed by: Ben Dawson | Director | 21 years experience in ground screw installation | Updated: August 2026

Ground Screws for Decking

Completed garden decking with outdoor furniture installed on ground screws

Building decking that stays level, stays dry, and lasts for decades starts with the right foundation. Gorilla Base installs ground screws for decking across the UK, providing a solid, permanent base without the disruption of concrete or the instability of timber posts sunk in the ground. DIY kits from £494 or professionally installed from £1,999 including screws, brackets, and structural timber frame. Over 500 decking projects completed since 2023.

Why Ground Screws Are the Best Foundation for Decking

Most decking problems — boards warping, structures becoming uneven, posts rotting — trace back to a poor foundation. Traditional timber posts buried in concrete absorb moisture over time and eventually fail. Ground screws eliminate this weakness entirely.

Driven directly into the soil using specialist equipment, our ground screws create a rigid, level mounting point for your decking frame. They do not rot, they do not shift, and they do not require weeks to set. Once installed, your decking frame goes on immediately.

Close-up of galvanised ground screw bracket connecting to timber decking frame

What Is Included in Our Decking Ground Screw Service

Every Gorilla Base installation for decking includes:

  • Ground screws, sized to suit your ground conditions and decking load
  • Galvanised steel joist brackets
  • Pressure-treated structural timber frame (minimum 44mm x 144mm, C16 or C24 grade)
  • Full professional installation by our trained team
  • Precise levelling across the entire footprint, including sloped or uneven ground

You do not need to source separate components or coordinate multiple contractors. We supply and install everything required to create a level, load-bearing base ready for your decking boards.

How We Install Ground Screws for Decking

Gorilla Base technician using hydraulic equipment to install ground screw
Step 1

Site Assessment

Before installation begins, we survey the ground conditions across your decking area. This tells us the correct screw length required and the spacing pattern needed to support the load.

Step 2

Ground Screw Installation

Using our specialist hydraulic or mechanical installation equipment, we drive each ground screw to the correct depth and height. We work to a levelling datum across the entire site, so screws on sloped or uneven ground are all brought to the same plane. No excavation is needed.

Step 3

Frame and Bracket Assembly

Once all screws are installed and level, we attach the galvanised brackets and build your structural timber frame on top. This frame is the base onto which you or your decking installer will fix the boards.

Step 4

Handover

Installation is typically complete within a single day. Your base is ready for use immediately — no curing time, no waiting.

Case Study: 5m × 4m Decking Installation, Bexleyheath, Kent

Barbara Dale from Bexleyheath, Kent contacted Gorilla Base after planning a 5m × 4m raised decking area for her garden, intended as a new outdoor seating and entertaining space for her and her husband. Barbara's original plan was for us to install the ground screw foundation only, with a separate contractor fitting the decking boards afterwards.

The site was relatively level, but poor access, three large tree roots and an existing tree stump made a traditional concrete base far less practical. Ground screws provided the ideal solution, allowing us to install a precision-engineered foundation with minimal disruption, no excavation and virtually no mess.

After the tree stump had been removed, our installation team installed 20 galvanised ground screws and completed the bespoke 5m × 4m structural timber subframe in just four hours, leaving a perfectly level, load-bearing base ready for the decking boards.

Once the frame was complete, Barbara and her husband began looking at fitting the decking boards themselves but quickly realised the job was more involved than they had expected. They contacted us again and asked if we could return to finish the installation. As Barbara and her husband were an elderly couple, we also went beyond the original brief by liaising directly with their decking board supplier on their behalf when a small number of components were found to be missing from the delivery. Although this isn't a service we routinely provide, we wanted to make the process as straightforward and stress-free as possible, ensuring the correct parts arrived before work continued.

Our installation team then returned and professionally fitted the decking boards. Had we been instructed from the outset to complete both the foundation and the deck itself, the project would normally have been finished in two days. Because Barbara initially intended to fit the boards herself before asking us to take over, the overall project was completed across three days.

Throughout the project, communication remained a key focus. Barbara later praised both our office team and our on-site installers for explaining every stage of the process clearly, keeping her informed throughout and ensuring the finished decking met her exact requirements.

"They installed the base for our garden decking. Talked us through the procedure and carried out the installation exactly to our needs. Guys were polite and very professional. Highly recommend this Company." — Barbara Dale, Bexleyheath, Kent (Google review)

Project Summary

  • Location: Bexleyheath, Kent
  • Project: Raised garden decking
  • Footprint: 5m × 4m
  • Use: Outdoor seating and entertaining space
  • Foundation: Gorilla Base ground screw foundation
  • Ground screws installed: 20
  • Ground conditions: Relatively level ground with poor access, tree roots and a tree stump removed before installation
  • Foundation installation time: 4 hours
  • Overall project duration: 3 days
  • Outcome: Complete ground screw foundation and professional decking installation, with ongoing customer support from start to finish

Ground Screws for Decking on Sloped or Uneven Ground

One of the most common challenges for decking in UK gardens is sloped ground. Concrete foundations on a slope require substantial excavation and shuttering, and costs escalate quickly. Ground screws solve this problem cleanly.

On a slope, screws on the lower side simply protrude further from the ground while screws on the higher side sit closer to the surface. The bracket height is adjusted accordingly, and the resulting frame is perfectly level regardless of the gradient beneath it.

We work regularly on gardens with significant slopes, terraced ground, and irregular surfaces. The same principles apply when you need shed bases on slopes — ground screws level the foundation regardless of the gradient. If your garden has presented a challenge for previous contractors, talk to our team about what ground screws can achieve.

Gorilla Base ground screws are also widely used as the foundation for garden rooms and garden offices — a larger application where the benefits of airspace and reversibility matter even more.

Ground Screws vs Concrete Posts for Decking

Ground Screws Concrete-Set Timber Posts
Installation time One day, immediate use Several days including cure time
Ground disruption Minimal Significant excavation required
Performance on slopes Straightforward Complex and expensive
Lifespan Lifetime warranty on screws Posts deteriorate over time
Environmental impact No cement, no waste High CO2, non-reusable
Removal Screws can be extracted and reused Posts and concrete left in ground

Which Ground Screw Length Is Right for Your Decking?

The correct screw length depends on your ground conditions, the load the decking will carry, and whether the ground is level or sloped.

For standard residential decking on flat, solid ground, shorter screws are generally appropriate. Where the decking will support heavier loads — a hot tub, outdoor furniture, or significant foot traffic — or where the ground is softer or more variable, longer screws provide additional load-bearing capacity.

Our team assesses your site before installation and selects the appropriate specification. All screws we install are galvanised steel, manufactured to meet load-bearing requirements. For further guidance on decking structural requirements, the Timber Decking and Cladding Association (TDCA) provides useful reference information for UK residential projects.

Get a Free Ground Screw Decking Quote

Tell us the size of your proposed decking area, your location, and any specific ground conditions we should know about. We will come back to you with a clear, fixed-price quote that covers screws, brackets, timber frame, and full installation. Our team works across the UK, completing most decking base installations within a single day.

Request your free quote today or call us on 07827 014408 to discuss your project.

Frequently Asked Questions

The quantity depends on the size of your decking and the spacing between joists. As a general guide, screws are positioned at a maximum of 1.5 metres apart when supporting a timber frame. Our team calculates the correct quantity during your site assessment and provides a clear specification before work begins.
Yes. Where additional load is present, we use longer screws or increase the number of screws in the relevant area to meet the required bearing capacity. Let us know at the quoting stage if your decking will support any unusually heavy items.
Our ground screws are suitable for the vast majority of UK soil conditions, including clay, sandy, and loamy soils. We can also install into compacted hardcore and tarmac, though some preparatory work may be required. We assess your specific ground conditions before installation.
In most cases, no. Residential decking that is not attached to the house and does not raise the surface above 300mm typically falls within permitted development. If your project falls outside these parameters, we recommend checking with your local planning authority. More information is available through the Planning Portal.
Most decking base installations are completed within a single day. Larger or more complex projects may take longer, and we will confirm the expected timeframe when we quote your job.
Yes. Unlike concrete, ground screws can be extracted and, in many cases, reused. This makes them a sensible long-term choice if your plans or garden layout may change in the future.
Gorilla Base provides a lifetime warranty on our ground screws. The screws themselves are galvanised steel and designed to outlast the structures built on them.
Finished raised decking area with chairs and table on Gorilla Base foundation

Tell us the size of your proposed decking area, your location, and any specific ground conditions we should know about. We will come back to you with a clear, fixed-price quote that covers screws, brackets, timber frame, and full installation.

Get a Free Quote