Top Tips for Building Raised Decking: A Trade Guide 

5th Aug 2024 -

Raised decking can transform outdoor spaces, providing an attractive and functional extension to any home. This article equips you with techniques and knowledge to elevate your decking projects. By the end, you will be able to build high-quality raised decking. 

• What is a Raised Deck?
• How to Plan a Raised Decking Project
• Top Tips on Adhering to Building Regulations
• How to Build Raised Decking: 9 Advanced Techniques
• 7 Raised Decking Finishing Techniques
• Shop Raised Decking Supplies with Fast Delivery Options

What is a Raised Deck?

​​A raised deck is an elevated outdoor platform. Unlike ground-level decks, raised decks are supported by posts or pillars. There are various other differences between raised decking and other decking types.

• Height: The primary difference is their elevation. Ground-level decks typically sit at most 30 cm (12 inches) above grade. In some cases, raised decks are significantly higher.
• Structure: Raised decks require a more complex support structure. They need strong vertical posts, robust beams and often diagonal bracing to ensure stability and safety at height.
• Foundation: While ground-level decks are built on a simple gravel base or concrete piers, raised decks require deeper, more substantial foundations. This securely anchors the support posts.
• Railings: Building codes instruct safety railings for any deck more than 60cm (24 inches) off the ground. 
• Permits: Because of their complexity and potential safety risks, raised decks require planning permission if they are 30 cm above ground level.

How to Plan a Raised Decking Project

Preparing for a raised deck project requires careful planning and consideration of various factors. You must address several key areas before breaking ground to guarantee a smooth, efficient and compliant build.

Site assessment

Conduct a thorough site survey to assess soil conditions, drainage patterns and potential obstacles. Check for underground utilities and obtain necessary clearances. Also, consider factors like sun exposure, prevailing winds and desired views.

Develop detailed plans and drawings, including elevation views and structural details. Calculate load-bearing requirements based on intended use and local climate conditions to ensure the deck's safety and longevity.

Material selection

Choose appropriate decking for your project. Options include PVC decking, timber decking or composite decking boards. Select fasteners that are suitable for outdoor use, such as galvanised, stainless steel or specially coated options. 

Consider the appearance and functional aspects when choosing railing materials, which could be wood, metal or composite. Be sure to select appropriate flashing and waterproofing materials to protect the structure from moisture damage.

Tool selection

Essential power tools include a circular saw, drill/driver, impact driver, mitre saw and post hole digger or power auger. Hand tools like a carpenter's square, level, tape measure, chalk line, framing hammer and pry bar are also important.

Consider specialised tools such as a joist hanger nail gun, deck board spacers and post level to improve accuracy. 

Common challenges

Raised decks often face challenges such as uneven terrain, poor drainage and difficulties in securing the deck to the property. Solutions include adjustable post bases for levelling, proper slope for drainage and using a properly flashed ledger board for attachment. 

In cold climates, extend footings below the frost line to prevent frost heave. To combat wood rot and decay, use pressure-treated lumber, apply water sealant and ensure proper ventilation. Address wobbling or swaying by installing diagonal bracing and establishing proper post-to-beam connections.

Measurements and calculations

Accurate measurements and calculations are key for a successful raised deck project. Determine the deck size based on intended use and available space. Plan spacing with decking joists, typically 16 inches on the centre for residential decks. 

Size beams according to span and load, consulting manufacturer span tables as needed. Space posts 6-8 feet apart, depending on beam size and load. For stairs, aim for a rise of 7-7.75 inches and a run of 10-11 inches. 

Residential decks require a minimum width of 36 inches. 

Top Tips on Adhering to Building Regulations

Adhering to building regulations ensures legal compliance and guarantees the safety and longevity of the structure. This checklist outlines the regulatory considerations for raised deck projects. 

• Local planning permission: Check if planning permission is needed, especially for decks over 30cm high or in conservation areas. Contact your local planning authority to confirm specific requirements for your area.
• Compliance with Part A: Design the deck to support a minimum load-bearing capacity of 1.5 kilonewtons per square metre (kN/m²). General domestic use requires a 1.5kN concentrated load, or 3kN/m² plus 1.5kN for areas expecting large gatherings. 
• Adhere to Part K: Install rails for any deck over 600mm high. Ensure rails are at least 1100mm high for decks up to 10m above ground, and 1200mm for higher decks. Space balusters no more than 100mm apart for safety. 
• Consider Part M: Make sure the deck design allows for easy access, including appropriate ramp gradients if necessary. For public buildings, adhere to specific accessibility requirements.
• Address Part B: Ensure the deck does not compromise existing fire escape routes. If the deck is part of an escape route, use appropriate fire-resistant materials. Keep the underside of the deck clear to prevent fire spread.
• Comply with Part C: Properly prepare the site, ensuring adequate drainage and damp-proofing. Use appropriate treatments for ground contact timber to prevent decay.
• Respect property boundaries: Ensure the deck does not overlook neighbouring properties. The deck should not exceed permitted development rights in terms of height and coverage area. This is usually no more than 50% of the garden area.
• Structural calculations: For complex designs or larger decks, have a structural engineer provide calculations to prove compliance with load-bearing requirements.

How to Build Raised Decking: 9 Advanced Techniques

Adopting advanced techniques in raised deck building can set your work apart. These methods enhance the quality and durability of the deck and expand design possibilities. With these approaches, you can tackle more complex jobs.

1. Cantilever decking

Cantilever decking involves extending the deck beyond its support structure, creating an overhang. This technique requires careful calculation of load distribution and the use of stronger, engineered lumber for joists. 

Specialised hardware like heavy-duty joist hangers and tension ties are essential. The benefit of cantilever decking is the ability to maximise deck space without additional support posts, creating a sleek appearance. 

2. Hidden fastener systems

Hidden fastener systems eliminate visible decking screw heads on the deck surface, resulting in a cleaner, more polished look. This involves using decking clips that fit into grooves on the sides of decking panels. 

Tools required include a groove cutter for non-grooved boards and a pneumatic fastener gun for faster installation. The benefits include improved aesthetics, reduced water penetration and minimised board warping. 

This method also allows for easier board replacement if needed in the future.

3. Integrated lighting systems

Incorporating a sophisticated lighting system into the deck design enhances look and functionality. This technique involves planning and installing wiring during the framing stage, using low-voltage LED systems for energy efficiency. 

Specialised tools include voltage testers, wire strippers and potting compounds for waterproofing connections. Integrated lighting systems improve safety, extend usability into evening hours and create ambience through lighting design.

4. Multi-level decking

Building a multi-level deck requires advanced framing techniques and careful planning for transitions between levels. This approach often involves using stepped footings, multiple beam heights and intricate joist layouts. 

Laser levels and string line setups are crucial for ensuring precise alignment across different elevations. Multi-level decking benefits include the ability to adapt to sloped terrain and create functional areas. 

5. Water management systems

Introducing advanced water management systems beneath a raised deck can transform the area below into usable space. This technique involves installing a series of channels, gutters, and downspouts to direct water away from the underside of the deck. 

Membrane systems and slope-creating underlayments are key components. These systems protect the deck structure from moisture damage, extend the lifespan and create functional space underneath for storage.

6. Post-tensioning

Post-tensioning is a technique widely used for concrete construction that can be adapted for large or complex raised decks. It involves running high-strength steel cables through the framing members and tensioning them after the deck is assembled.

Tools for post-tensioning include cable tensioners and anchor systems. The benefits of post-tensioning include increased span capabilities, reduced deflection and improved overall structural integrity.

7. Pneumatic joist hanging

This technique uses pneumatic nailers specifically designed for installing joist hangers and other metal connectors. It significantly speeds up the framing process while ensuring consistent, strong connections. 

The tools required include a pneumatic nailer and compatible fasteners. Pneumatic joist hanging increases efficiency and offers a more uniform installation. 

8. Threaded rod connector system

For this method, you use long threaded rods to tie the deck structure together from the footings to the railings. It requires careful pre-planning and drilling to align all components. Long drill bits and rod tensioning equipment are needed for this technique.

You build a more rigid overall structure with improved resistance to lateral forces. Also, it offers the ability to create cleaner-looking connections without visible bolts or brackets.

9. Composite deck board end capping

This technique involves using composite end caps to cover the exposed ends of composite decking boards. It requires precise cutting and often uses colour-matched caulk or epoxy fillers. 

The tools needed include fine-toothed saws for clean cuts and specialised applicators for fillers. It creates a more polished look to the deck edges, protects against moisture intrusion and can create seamless transitions.

7 Raised Decking Finishing Techniques

Proper finishing boosts the longevity, appearance and performance of raised decking. The following methods represent the cutting edge in deck finishing, offering ways to deliver superior results to your clients.

1. 2-stage staining process

This involves applying a penetrating oil-based decking stain followed by a water-based top coat. Use a high-quality, penetrating oil-based stain that soaks deep into the wood fibres. After drying time (48-72 hours), apply a water-based, UV-resistant clear coat.

The 2-stage method offers superior protection against moisture and UV damage. The oil-based decking stain provides deep protection. Also, the water-based top coat provides an additional barrier against the elements. 

Overall, this combination may extend the deck finish by 2-3 years compared to traditional single-stage staining.

2. Hardwax oil treatment

Hardwax oil penetrates the wooden decking boards and forms a protective, yet breathable layer. Apply the product in thin layers, allowing each to penetrate before applying the next (8-12 hours). Buff the final coat for a smooth finish.

This deck oil treatment provides excellent water and stain resistance. It is particularly effective for hardwoods and offers a more natural look compared to traditional sealers. The finish is easily repairable and does not peel or flake.

3. Powder coating for metal components

For decks with metal railings or balusters, powder coating offers superior protection. This involves electrostatically charging dry powder and spraying it onto the metal surface, then curing it under heat.

Powder coating offers a durable, uniform finish that is more resistant to chipping, scratching and fading compared to traditional paint. It also delivers excellent protection against corrosion, extending the life of metal components. 

4. Thermal modification of decking boards

It involves heating wood to very high temperatures (typically around 204°C) in a low-oxygen environment (specialised kiln). This process changes the cellular structure of the wood, making it more stable and resistant to decay.

Thermally modified wood is highly resistant to warping, cupping and twisting. It also becomes naturally resistant to rot and insect infestation without the need for chemical treatments. Overall, it turns softer, less durable woods into excellent decking materials. 

5. Nano-ceramic clear coatings

These clear coatings use nano-ceramic technology to create an extremely thin, yet durable protective layer on the deck surface. Apply with a sprayer or fine brush for even coverage.

Nano-ceramic coatings offer exceptional UV and moisture protection while being nearly invisible. They do not yellow over time and maintain the natural look of the wood for longer periods. These coatings deliver excellent scratch and chemical resistance. 

6. Hydrophobic sealing

This involves applying a hydrophobic (water-repelling) sealant that forms a molecular bond with the wood fibres. The sealant is typically clear and is applied by spraying or brushing onto clean, dry wood.

Hydrophobic sealers provide superior water resistance, preventing moisture from penetrating the deck. It greatly reduces the risk of rot, mould and water damage. The molecular-level bond means the treatment lasts longer than traditional sealers.

7. Elastomeric deck coatings

These thick, rubber-like coatings can be applied over wood decking surfaces. They are typically rolled on in multiple coats to build up a thick, flexible layer.

Elastomeric coatings offer excellent waterproofing and can bridge small cracks in the decking surface. They are beneficial for older decks or over-living spaces where water penetration is a main concern. 

These coatings also provide a non-slip surface, enhancing safety.