Building a Raised Deck: What You Need to Know About Safety, Structure and Regulations
- Joel Livesey
- 23 hours ago
- 9 min read
A clear guide for UK homeowners planning an elevated decking project
Raised decking can completely transform a garden — opening up views, creating level access from the house, and making sloped or uneven ground usable. But once a deck is raised above ground level, safety, structure, and UK building regulations become just as important as how it looks.
At Duralive Decking, we design and build raised composite decking across Merseyside and Cheshire, and one of the most common questions we’re asked is:
“Do I need building regulations for a raised deck?”
The answer depends on height, location, and design — and getting it wrong can lead to costly changes later. This guide explains everything homeowners need to know before building a raised deck.
What Counts as a Raised Deck in the UK?
In simple terms, a deck is considered “raised” when:
The walking surface is more than 300 mm (30 cm) above ground level, or
A fall from the deck could cause injury
Once you exceed this height, guarding, balustrades, and structural considerations come into play under UK Building Regulations.
Do You Need Building Regulations Approval for a Raised Deck?
In England and Wales, raised decking is covered under Approved Document K (Protection from Falling, Collision and Impact).
Building Regulations approval is typically required when:
The deck surface is over 300 mm above ground
The deck is adjacent to a drop, slope, or retaining wall
Guarding or balustrades are needed
The deck forms part of an access route from the house
Planning permission is not always required, but Building Regulations compliance is still essential, even if planning permission isn’t.
Important: Local authorities may interpret requirements differently. At Duralive Decking, we always design raised decks to meet or exceed regulation standards — even where approval isn’t strictly enforced.
Balustrade and Guarding Requirements (Approved Document K)
When is a balustrade required?
A balustrade or guarding system is required where:
There is a drop of more than 600 mm
There is a risk of falling from the edge of the deck
Key regulation requirements
Minimum height: 1100 mm for domestic external decking.
Load resistance: Must withstand horizontal loads (typically 0.36 kN/m for residential use).
No climbable gaps: Openings should prevent children climbing or falling through.
Secure fixing: Guarding must be structurally fixed, not surface-mounted as an afterthought.
Gap sizing: Openings within balustrades must not allow a 100 mm sphere to pass through.
This is where professional design and installation really matter.
Balustrade Systems for Raised Composite Decking
A balustrade’s primary role is to prevent falls and protect people using the deck — especially children, pets, and guests who may not be familiar with the space. While appearance is important, the system must first meet UK Building Regulations, withstand required loads, control gaps, and remain secure over time. Once those safety and structural requirements are satisfied, the design can then be tailored to suit the style of the property — whether that’s sleek glass panels, modern aluminium rails, or a composite system that complements the decking itself.
Glass Balustrades
Glass balustrades are a popular choice for modern homes, especially where views are important. They provide a high level of safety without visually enclosing the space, making them ideal for raised decks overlooking gardens, open landscapes, or contemporary extensions with large glazing.
One of the biggest advantages of glass balustrading is how it preserves light and openness. Unlike traditional spindles or solid panels, glass allows uninterrupted sightlines, helping smaller gardens feel more spacious and elevated decks feel less imposing. This makes them particularly well suited to properties in Merseyside and Cheshire where raised decks are often used to step down into sloping gardens.
From a technical perspective, glass balustrades must be properly engineered and fully compliant with UK Building Regulations.
At Duralive Decking, we only specify tried-and-tested glass balustrade systems from reputable suppliers. Each system is designed as an integral part of the deck structure from the outset, with the subframe reinforced where posts or base channels are required and load paths carefully managed.
Pros:
Clean, contemporary appearance
Maintains light and visibility
Ideal for elevated garden outlooks
Considerations:
Must be properly engineered and tested
Glass may require maintenance to keep it clean.
Composite Balustrades
Often matched to the decking colour for a cohesive look, composite and aluminium balustrades help tie the entire scheme together visually. Using the same or a complementary tone creates a sense of continuity across the deck, steps, and edges, giving the finished space a more considered, architectural feel. When done well, the balustrade doesn’t stand out as a separate add-on — it becomes a natural extension of the decking design, reinforcing clean lines and a premium, professionally finished appearance.
Pros:
Durable and low maintenance
Can be colour-matched to NewTechWood or Trex decks
Offers privacy where required
Important note: Some manufacturer balustrade systems are not fully Building Regulations compliant for raised decks. Where this is the case, we make this clear and advise on compliant alternatives or written client acknowledgment where appropriate.
Timber or Steel Balustrades
Less common on composite decks but still suitable in certain designs, timber and steel balustrades can work particularly well where a more traditional, industrial, or architectural look is desired. These systems are often chosen to complement existing features such as brickwork, rendered walls, or steel-framed extensions, helping the deck sit comfortably within the wider design of the property.
When specifying timber or steel balustrades, careful attention must be given to structural fixing, corrosion protection, and long-term durability. Steel systems must be properly treated or powder-coated for external use, while timber balustrades require appropriate detailing and ongoing maintenance. As with any raised deck, these balustrades must still meet UK Building Regulations for height, load resistance, and gap sizing to ensure safety and compliance.
These systems must be:
Structurally engineered
Correctly spaced
Securely fixed to the primary structure
Structural Requirements for Raised Decks
A raised deck isn’t just a surface — it’s a load-bearing structure. Every raised deck must safely support not only the weight of the decking boards themselves, but also the combined loads of furniture, planters, balustrades, and the people using it day to day. On top of that, the structure must remain stable in all weather conditions, resisting movement, deflection, and long-term settlement. This is why raised decking needs to be designed from the ground up, with correctly sized posts, accurately calculated joist spans, secure fixings, and properly formed foundations.
Subframe design
When constructing a raised deck using a traditional timber framework, use class 4 timber posts should always be specified where posts are in contact with the ground. These posts are pressure treated for direct ground contact and provide the durability required for long-term structural support. As a general guide, when using a 6×2 timber framework, posts are typically set at maximum 1600 mm centres to maintain strength and stability.
It’s important to note that post spacing can vary significantly depending on the deck height, loading, timber grade, and alternative materials or section sizes being used. There is no one-size-fits-all solution. Where designs fall outside standard parameters, or where aluminium or composite structural systems are specified, spacing and fixings must be assessed accordingly. If in doubt, we always recommend seeking professional advice — either by contacting us at Duralive Decking or consulting a structural engineer to ensure the deck is designed safely and correctly.
Foundations
Solid foundations are essential to the long-term performance of any raised deck. Each support post must be set onto a properly formed concrete footing that is sized to suit the height of the deck, the loads being carried, and the ground conditions on site. Shallow or undersized foundations can lead to settlement over time, causing the deck to drop, twist, or fall out of level.
As a general rule of thumb, around one third of the total post length should be set below ground level. For example, if a post supports a deck that sits 1 metre above ground, the post should typically be installed with a minimum of 500 mm embedded into the ground. This helps provide sufficient resistance against movement, uplift, and lateral forces.
In practice, footing depth and diameter will still vary depending on soil type, drainage, exposure, and overall deck height. Softer ground, sloping sites, or decks supporting balustrades and built-in features may require deeper or wider foundations than this basic guide suggests. Where ground conditions are uncertain or loads are higher than normal, professional assessment is essential.
Fixings and connections
The strength of a raised deck relies not just on the materials used, but on how those materials are connected together. All structural fixings must be suitable for external use and capable of withstanding long-term exposure to moisture, temperature changes, and movement. This typically means using structural-grade, corrosion-resistant fixings throughout the build.
It’s also important to consider bi-metallic corrosion, particularly where different materials meet. This occurs when two dissimilar metals come into contact in the presence of moisture, causing accelerated corrosion over time. For example, fixing certain stainless-steel or galvanised components directly to aluminium subframes without the correct fixings or isolation can lead to premature failure. Using the correct fixings — and, where required, isolating materials — is essential to protect the structure and ensure long-term durability.
Correct fixing selection and installation prevents loosening, movement, and premature degradation, ensuring the deck remains safe, rigid, and secure for years to come — even in the challenging North West climate.
Stairs, Steps and Access
Where a raised deck includes steps, careful design is essential to ensure the deck is safe, comfortable to use, and compliant with UK Building Regulations. Steps are one of the most heavily used parts of any deck, and small mistakes in layout or detailing can quickly become both a safety issue and a visual distraction.
Under Approved Document K, steps and access routes must be designed to minimise the risk of trips and falls. In practice, this means paying close attention to proportions, consistency, and surface performance.
Key considerations include:
Consistent tread and riser heights
All steps should be uniform. Even small variations in riser height can catch people out and significantly increase the risk of trips or missteps. As a general guide, we typically aim for a riser height between 150 mm and 180 mm, which provides a comfortable, natural stride for most users. Keeping risers within this range helps steps feel predictable and easy to use, particularly when moving between the house and garden or when steps are used frequently throughout the day.
Handrails where required
Depending on the overall rise and configuration of the steps, handrails may be required to provide additional support and protection. Where specified, handrails must be securely fixed and positioned at the correct height to be effective.
Clearly defined nosings
Step edges should be visually clear, particularly in low light. This can be achieved through board layout, colour contrast, or subtle lighting, helping users easily identify each step as they move between levels.
Slip resistance
External steps are exposed to rain, frost, and algae growth, so slip resistance is critical. The surface should provide reliable grip in all weather conditions, especially in high-traffic areas.
This is where composite decking performs exceptionally well. Unlike timber, high-quality composite boards offer consistent slip resistance, don’t splinter, and don’t require additional coatings to remain safe underfoot. This makes them particularly well suited to steps in the North West climate, where wet conditions are common for much of the year.
Why Professional Design Matters
Raised decking is one of those projects where experience really shows. While a raised deck may look straightforward on the surface, the reality is that it brings together structure, safety, regulations, and design — and all of those elements need to work together properly.
Poorly designed raised decks often look fine at first, but issues tend to surface over time. Common problems include movement in the structure, non-compliant balustrades, or layouts that simply don’t feel right to use day to day. In many cases, these issues only come to light when a deck is inspected, sold with a property, or subjected to heavier use.
Poor design can lead to decks that:
Fail Building Control inspections or raise concerns during property surveys
Become unsafe over time, with flexing, loose fixings, or inadequate guarding
Require costly retrofits to balustrades, posts, or foundations that could have been avoided with proper planning
Suffer premature wear due to incorrect material selection or inefficient layouts
This is why professional design isn’t an optional extra — it’s a fundamental part of building a raised deck correctly. When structure, safety, and regulations are considered together from the outset, the result is a deck that not only looks great, but remains safe, compliant, and enjoyable to use for years to come.
Thinking About a Raised Deck? Let’s Get It Right from the Start
A raised deck can be a fantastic addition to your home — creating usable space, improving access, and transforming how you enjoy your garden. But as we’ve covered, once a deck is raised, design, structure, and safety become just as important as appearance.
At Duralive Decking, our free design service ensures every raised decking project is properly thought through before work begins. We take the time to understand your site conditions, deck height, access requirements, and how the space will be used, so nothing is left to chance.
Our design-led approach ensures:
Compliance with UK Building Regulations, including Approved Document K
Correct balustrade selection, based on safety, load requirements, and gap control
Efficient material use, reducing waste while maintaining strength and visual balance
A clean, professional finish, where structure, detailing, and design work together seamlessly
We don’t just build decks — we design and construct safe, compliant outdoor structures that perform as well as they look. The result is a raised deck you can enjoy with confidence, knowing it’s been built properly from the ground up.
👉 If you’re considering a raised deck in Merseyside or Cheshire, we’d be happy to talk it through. Contact Duralive Decking to arrange a site visit and free design consultation.
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