How To Build A Raised Deck On Pedestals

There are many things to consider when building a new decking area. Location, materials, size, and style are all important factors.

Decking installation should always follow the supplier guidelines, and you should use the components and accessories provided. Failure to correctly install your decking can invalidate product warranties and compromise their performance and longevity.

One excellent way to ensure your decking is protected from prolonged exposure to moisture is by raising it. This can be done with a subframe or by using adjustable pedestals.


Decking Pedestals

Adjustable pedestals are used to raise and support the joists, which then support the decking boards.

Adjustable pedestals can be used on a variety of surfaces, and aluminium, wood, and plastic joists can be used with them.


Decking Pedestal Benefits

While decking projects don’t necessarily require pedestals, there are a number of benefits that make them a worthwhile investment.


Adjustable pedestals can be used on a variety of surfaces, making them an excellent option for decking projects.

Whether you have an existing patio, lawn, or concrete area or want to build your decking over the soil, it is possible to do this using adjustable pedestals.

Ecoscape adjustable pedestals can be used with aluminium, wood, plastic, or composite joists, depending on the subframe material you choose.

Investing in aluminium or composite subframe will improve the longevity of the decking and minimise any maintenance required.

Raise the Subframe and Decking from the Ground

Building a raised deck improves drainage and ventilation, meaning the materials you use won’t be exposed to moisture for long periods of time.

Drainage and ventilation are an essential part of deck installation and raised decking with a slight gradient and thermal expansion gaps will allow air to pass below and through the decking area, helping to dry it out and regulate its temperature.

Makes Installation Easier on Multilevel Surfaces

If you want to install a composite decking area, but your garden has one or more steps leading down to your garden, adjustable decking pedestals can help to create a level decking area.

A slightly sloped roof or garden can also be difficult to work with unless you make use of pedestals to level the area out.

There is a wide range of pedestal sizes to choose from, which are perfect for residential and commercial projects.

Easy Installation

While professional installation is recommended to guarantee a quality installation, it is possible to install your own composite decking with the right experience.

Ecoscape offers expert advice and a pedestal calculator to help you work out the pedestals needed for your job, and from there, you will be able to use them before joining joists and creating a secure subframe for your deck boards to be installed on.

Maintenance Access

If workers need access to outside areas covered by a deck, this can lead to the expensive removal of deck boards or sections.

Allowing space beneath the decking boards for people to easily access pipes, cables, or other access routes is essential. It will make it significantly easier for work to be carried out and shouldn’t affect your decking.


Building a Raised Deck on Adjustable Pedestals

Building a raised deck on adjustable pedestals is a relatively straightforward task. Simply follow this guide for advice on the steps needed to safely and securely install your raised deck.

Always follow the decking supplier installation guide to ensure you don’t invalidate your warranty and get the best performance from your deck.

Step 1 – Planning

The first step will be planning where you want your decking to be installed and carefully measuring it out.

You should consider access points, how the sun interacts with your garden, and privacy issues with neighbours during the planning process.

Decking that is raised above 30 cm will typically require planning permission in the UK, but checking with your local planning authority will minimise the risk of issues.

Step 2 – Preparation

Preparing the area for your pedestals is important. If you are lucky, the area won’t need a significant amount of work.

Depending on the surface, you may need to lay a geotextile membrane to prevent weed growth.

You should ensure the area is level by using a spirit level and remove any obstacles in place. A slight incline away from your property of around 2% should be enough to drain rainwater.

If you are installing concrete or slabs, always check the condition of it before you start working.

Step 3 – Space the Pedestals

You should then plot and space your pedestals accordingly based on your measurements and decking type. Composite deck boards are relatively heavy so require greater support.

Step 4 – Install the Pedestals

After planning out where the pedestals should be positioned, you should lay them out. You will be able to anchor them in place depending on the surface. Alternatively, you will have a floating installation.

Floating pedestal installations are when the pedestal is not secured to the ground, and the weight of the materials it supports holds it in place.

Step 5 – Laying your Joist Frame

After choosing your joist material, you will be able to lay them on the pedestals at a right angle to the way your decking boards will run.

When screwing the joists into the pedestals, take care not to damage the pedestal mechanisms.

Step 6 – Lay your Composite Decking Boards

Laying Ecoscape composite decking boards is relatively straightforward, and you can access the full composite decking installation guide for further advice.

Using hidden fasteners rather than decking brackets will give a cleaner finish and allow for thermal expansion without the worry of warping. You should use all the accessories and parts supplied by the manufacturer.


Ecoscape Adjustable Decking Pedestals

Investing in high-quality products will ensure your decking is long-lasting and requires minimal upkeep. Ecoscape’s excellent range of composite products and adjustable decking pedestals provide long warranties and an eco-friendly way of improving your garden.

Made from 100% recycled polypropylene, there are two ranges of Ecoscape pedestals.

The Queen adjustable pedestal is available in a range of sizes, and additional components can be added to create self-levelling support.

The King pedestal has either a fixed or adjustable base and a high compression rating.

The products come with a 15-year limited warranty as well as a 50-year design life.

For more product specifications, installation guides, and prices, visit the Ecoscape decking pedestal page.



How much do adjustable pedestals cost?

Adjustable pedestal prices will vary depending on the manufacturer and product size. Ecoscape King decking pedestals vary in price from £3.80 for the 30 mm to 30 mm pedestal to £16.72 for the 979 mm to 1,089 mm pedestal.

Ecoscape Queen adjustable pedestals vary in price from £2.45 for the 29 mm to 44 mm pedestal up to £16.93 for the 1,114 mm to 1,224 mm pedestal.

What gradient should the slope on a composite deck be?

Composite decks are naturally resilient to the UK weather, but they should still have a slight gradient of 1% to help water runoff.

When laying your deck, you must ensure that the deck board grooves run with the gradient so the water can easily run down and away from the property and does not pool on the deck.

What size of gap should be left under a composite deck?

As well as drainage, ventilation is essential for decking, and a gap of between 12 and 18 inches should be left below the deck.

Planning for ventilation allows air to move freely below the boards and between the thermal extension gaps. This helps to dry out the boards and the area beneath and regulate the temperature.

Do you need adjustable pedestals for a decking project?

Adjustable pedestals are optional for decking projects. When you consider the benefits that they offer and how easy they are to install, they are a worthwhile investment.

Adjustable pedestals can help to raise a deck if there is a difference between the ground floor of a property and the outside space. They also help to create a secure structure that can safely hold your deck boards for years.

Allowing timber joists to be exposed to moisture can compromise the structural integrity of the material. Raising your decking and joist materials from the ground helps to protect them.


Final Thoughts

Decking pedestals are an excellent alternative to decking posts and a great way to raise support beams, joists, and decking from the surface you are building over.

You should always follow the supplier’s instructions when it comes to installing decking pedestals, joists, and the deck itself. This is because the guide they create is made specifically for the product they have designed.

Failure to follow the guides or use the components and accessories provided can result in the warranty being void and the deck not performing as well as it could.

Gary is the founder and CEO of Ecoscape UK. Gary graduated from Liverpool JM University in 2007 with a 2:1 in Economics. A passion for innovation, design and sustainability, Gary has put to market numerous wpc products/systems, some of which have UK and European registered designs. Outside of work Gary enjoys spending time with his family, the great outdoors and watching Manchester United.