How to Pour Concrete Deck Footings: A Step-by-Step Guide

A beautiful garden deck can transform your outdoor space, creating the perfect spot to relax, entertain, or enjoy the sunshine. But before you lay decking boards, get one important job right: the foundations.

Concrete deck footings provide a strong, stable base for your decking structure, helping to distribute its weight and prevent movement, sinking or uneven settling over time.

Whether you’re building a small garden deck or a larger raised structure, getting the footings right from the start can save you plenty of headaches later.

In this guide, we’ll walk you through pouring concrete deck footings, from planning and preparation to pouring and curing.

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What Are Concrete Deck Footings?

Concrete deck footings are foundations installed beneath a decking structure to support its weight and transfer the load safely into the ground.

Instead of letting decking posts rest directly on the soil, concrete footings provide a stable foundation that helps protect the structure from ground movement and settlement.

There are several types of concrete footings used for decking, including:

• Concrete pad footings: Wider concrete bases designed to spread the load across the ground.
• Concrete pier footings: Deeper concrete foundations, often circular, that support individual decking posts.
• Concrete footings with post anchors: Foundations fitted with metal brackets that hold timber posts above ground level, helping to reduce moisture exposure.

The best option depends on your deck’s size and design, the ground conditions, and the weight the structure needs to support.

What You’ll Need to Pour Concrete Deck Footings

Before you start, make sure you have everything you need.

Tools and materials:

• Trowel
• Spirit level
• Suitable concrete
• Metal post anchors or brackets
• Spade or post-hole digger
• Tape measure, wooden pegs and string line
• Formwork or concrete footing tubes, if required
• Gravel or suitable sub-base material, where specified
• Protective gloves, safety boots and eye protection

You’ll also need to plan how the concrete will reach the footing holes. If you’re ordering ready-mix concrete, check that there’s suitable access for delivery.

How to Pour Concrete Deck Footings: Step by Step

With your materials ready and your deck layout planned, it’s time to prepare the foundations.

Step 1: Plan and Mark Out Your Deck Footings

Start by deciding exactly where your deck will sit and marking the footing positions.

Use wooden pegs and string lines to establish the deck’s outline, checking that everything is square and correctly aligned.

The number and spacing of footings will depend on the size of your decking, the supporting framework and the loads it needs to carry.

For larger or raised decks, it’s especially important to follow a suitable structural design rather than guess the spacing.

Top tip: Double-check your measurements before digging. It’s much easier to move a wooden peg than a finished concrete footing!

Step 2: Dig the Footing Holes

After marking the positions, start digging using a spade or post-hole digger, and excavate each hole to the required depth and width.

The correct dimensions will depend on several factors, including:

• Ground conditions and drainage
• The type and bearing capacity of the soil
• The risk of frost-related ground movement
• The size and weight of the decking structure
• The depth needed to reach suitable, stable ground

There isn’t a specific footing depth for every decking project. Always follow the structural design and any applicable building requirements.

Before digging, check for underground pipes, cables and other services.

Step 3: Prepare the Base and Formwork

Once you’ve excavated the holes, remove any loose soil, debris, or standing water.

The bottom of each excavation should provide a firm, suitable bearing surface.

Depending on the footing design, you may need to install a compacted granular layer, concrete footing tubes or other formwork to maintain the correct shape and dimensions.

Make sure any formwork is properly positioned and secured before pouring.

If the design specifies steel reinforcement, install it with the correct positioning and concrete cover.

Step 4: Choose the Right Concrete

Choosing suitable concrete is essential for strong, durable deck footings.

The concrete must provide adequate strength for the intended structure and withstand the ground conditions it will face.

The appropriate specification depends on factors such as loading, soil conditions and exposure to moisture or potentially aggressive ground.

For smaller projects, mixing concrete by hand might seem straightforward, but preparing several footings can quickly become time-consuming.

Ready-mix concrete can make the job easier, especially when you need to pour multiple footings.

With ready-mix concrete delivered, you can spend less time mixing batches and more time getting the foundations right.

Step 5: Pour the Concrete Deck Footings

With the holes prepared and the concrete ready, you can begin pouring.

Carefully place the concrete into each footing excavation or formwork, ensuring it fills the required space.

As you pour, consolidate the concrete appropriately to reduce trapped air and ensure it surrounds any reinforcement.

Avoid allowing loose soil or debris to fall into the fresh concrete.

Continue placing the concrete until it reaches the specified level, then use a trowel to finish the top surface as required.

Check levels carefully, especially where several footings support a level decking framework.

Top tip: Avoid adding extra water to make the concrete easier to pour. Too much water can reduce its strength and durability.

Step 6: Install the Deck Post Supports

Many decking designs use metal post anchors or brackets to secure timber posts to the concrete foundations.

These help provide a secure connection between the footings and the decking structure, while keeping timber away from direct contact with the ground.

Some anchors are designed to be positioned in fresh concrete, while others are fixed after the concrete has hardened.

Always follow the manufacturer’s installation instructions and the structural design.

Check that the supports are correctly aligned and positioned before moving on to the next stage.

Step 7: Allow the Concrete to Cure

Once you’ve poured your concrete deck footings, give them time to develop sufficient strength.

Concrete doesn’t simply dry out. It hardens through a chemical process called hydration, which requires appropriate moisture and temperature.

Protect the fresh concrete from rapid drying, heavy rain, freezing temperatures and accidental disturbance.

Concrete strength develops over time, with 28 days commonly used as a reference point for specified strength. However, that doesn’t mean every footing needs to remain unloaded for exactly 28 days.

The appropriate waiting period depends on the concrete specification, weather conditions and the loads being applied.

Don’t start building on the footings until they’ve developed sufficient strength for the next stage of construction.

Need Expert Advice?

Speak to the team at Flowmix Tewkesbury, Gloucestershire or Aldridge, Walsall. We are happy to help with all your concrete requirements. Contact us by email or telephone.

Flowmix Tewkesbury: Tel: 01684 217888 Flowmix Walsall: Tel: 01922 741731

Common Mistakes to Avoid When Pouring Concrete Deck Footings

Even a well-designed deck can develop problems if the foundations aren’t installed correctly.

Here are some common mistakes worth avoiding.

1. Digging footings too shallow: Footings must reach suitable bearing ground and meet the required design depth. Insufficient depth can contribute to settlement or movement.
2. Getting the spacing wrong: Incorrect footing positions can leave parts of the decking framework inadequately supported.
3. Using unsuitable concrete: Not all concrete specifications suit every application. Choosing the right mix helps ensure the foundations achieve the required strength and durability.
4. Adding too much water: Adding unnecessary water can weaken the finished concrete and increase the risk of cracking.
5. Poor consolidation: Trapped air and voids can affect the quality of the finished footing, particularly around reinforcement.
6. Building on the footings too soon: Fresh concrete needs time to gain strength. Applying structural loads prematurely can compromise the foundations.

Taking care at each stage helps you build a stronger, more reliable base for your decking.

Do You Need Planning Permission for Garden Decking?

Before you start your project, check whether planning permission or Building Regulations approval may be required.

In the UK, certain decking projects may fall under permitted development rules, but restrictions apply, including limits on height and the area of garden covered.

Raised decks, decks attached to buildings and projects on properties with additional planning restrictions may need further consideration.

Rules also differ across the UK, so check with your local planning authority before beginning work.

For substantial raised decking, professional structural advice is advisable to ensure the foundations and supporting framework are suitable.

Conclusion

Strong decking starts with solid foundations, and choosing the right concrete is key to getting the job done properly.

Whether you’re installing concrete deck footings for a garden makeover or working on a larger landscaping project, having suitable concrete delivered when you need it can make the process much easier.

Flowmix supplies ready-mix concrete for a wide range of domestic and commercial applications, helping you get the concrete you need for your project without the hassle of mixing it yourself.

Not sure how much concrete to order or which specification you need?

Contact the Flowmix team to discuss your requirements and arrange concrete delivery for your next project.

How Flowmix Can Help with Your Project

Flowmix has two plants, Gloucester and Walsall. We provide the following services (with time slots):

✅ Ready-mix concrete, mix on-site (volumetric concrete)
✅ Traditional and liquid screed.
✅ Concrete line pump Hire to reduce manual labour and associated costs, increase efficiency, reduce wastage and clean up.
✅ Interlocking concrete blocks for temporary or permanent barriers.
✅ Mini-Mix loads up to 4 cubic metres.

Flowmix holds the BSA-approved Ready Mix Concrete Kitemark KM683844, a certification that “confirms a product or service’s claim has been independently and repeatedly tested by experts” (source BSI).

Flowmix Tewkesbury: Tel: 01684 217888 Flowmix Walsall: Tel: 01922 741731

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