How Do I Calculate How Much Decking I Need?

Embarking on a decking project can be an exciting time. It allows you to transform your outdoor space and enjoy your garden all year round.

It’s important that you determine how many decking boards you will need for the project. But how can you accurately do this?

This article will tell you everything you need to know about the Ecoscape decking board calculator.

Why Is A Composite Decking Calculator Helpful?

Using a decking calculator will allow you to work out how many deck boards are required for your project.

Good decking calculators also let you know the support materials required. This can include pedestals and plastic posts, as well as the substructure materials you will need.

How Do I Calculate How Much Decking I Need?

Using a decking calculator is relatively simple. However, you will need measurements and an idea of the style you want for your decking.

By entering the deck or patio shape and laying direction, you will be given a composite decking board calculation to suit your needs.

The Ecoscape decking calculator provides a range of the most common decking shapes to choose from.

This will then be broken down into the individual measurement requirements for each side of the decking area.

You will also be required to enter the build-up level or FFL (Finished Floor Level.)

You will then be able to select whether you plan to use decking board support pedestals or a substructure. From there, you will be able to make further selections for the exact materials you want to use.

Your laying calculation will then be entered. This informs the decking board calculator of your support distances and laying direction.

The final section will take you through the accessories required to finish composite decking projects. This includes:

You will then be provided with an estimate for the cost of the materials you will need for a high-quality composite deck.

Please note that the details you get from the decking calculator are only an estimate based on the figures you provide. If you are unsure, contact us for further decking design advice.

Should Deck Boards Be Butted Together?

When laying composite decking boards, it’s essential that a gap be allowed for thermal expansion.

Composite decking won’t warp due to moisture or heat as traditional wood decking can. However, it can still expand and contract at different temperatures.

Composite decking boards that are tightly fitted together can push against one another in the heat. This can cause the boards to warp.

Always follow the installation guide to ensure you leave the right size of gaps between each decking board. You should allow 3 mm to 6 mm of space between each composite decking board. The table at the end of the installation guide suggests the correct gap to leave, which is always dependent on the temperature and length of the deck board.

Gaps also allow for drainage and airflow. This is essential to your decking area to stop pooling and moisture lingering. This can lead to the decking becoming slippery and the growth of mildew or mould.

Can I Use Decking Board OffCuts?

Decking board offcuts can be used for a number of purposes. This includes creating planters for your decking area that blend in seamlessly. The offcuts can also be used within your deck design to minimise waste, saving money. When estimating the number of boards needed for your project, try to use any offcuts in your design. When possible, try to alter the length and width of your deck to accommodate the offcuts in your calculations.

They can also be used to test cleaning methods and products. When cleaning composite decking boards, you should avoid using abrasive cleaning materials. Harsh chemicals should also be avoided.

Using offcuts to test cleaning products determines whether they would damage your decking area. You can also test power washers to ensure they won’t leave marks on your decking.

How Many Clips Are Needed Per M2?

To install Ecoscape composite decking boards, you will need start and finish clips, locking clips, and hidden T-clips.

Starter clips and finish clips are only used on the first and last decking boards. Hidden T-clips are used on each joist to secure the end of each decking board. We estimate 250 clips will cover approximately 15m2 of our 150 mm wide composite decking board.

Locking clips are installed to stop the board from sliding and to control thermal expansion and contraction. One will typically be used per composite decking board and be used at the centre of the board, you will need to allow for this in your estimate.

For more information, take a look at our composite decking installation guide.

How Should Joists Be Spaced?

Ecoscape advises spacing joists at 400mm intervals. They must be fixed in at least 3 places using A4 stainless steel countersunk masonry or wood screws.

It’s essential that the subframe is adequate for the decking. Failure to adhere to Ecoscape’s guidance can result in the warranty being invalidated.

Please note that if you’re choosing our 125x50mm plastic joists, you will need to make sure a plastic post is calculated every 1500mm.

How Do You Work Out M2 On A Deck?

Working out m2 on a deck is straightforward if you are dealing with a square or rectangle. Simply multiply the width by the length to work out the total surface area.

For more complicated shapes, our decking calculator will help. It’s often a good idea to draw a diagram of the area and add the measurements into the calculator as you go. The calculator will estimate exactly how many decking boards are required.

When calculating your decking requirements, you should also consider the gaps between the boards. However, allowing around 10% excess is advised in case of damaged boards.

Working out how many boards you need for your new deck is entirely dependent on the board type.

In the case of Ecoscape composite decking boards, the Forma and Clarity collections are available in 3000 and 4800mm lengths with a width of 150mm.

The Grande collection is only available in 3600mm by 225mm boards. You can find out the material quantities required and costs by using our calculator.

Once you have calculated the total m2 of your deck, the quantity of boards will be quantified in your estimate.

How Much Does Composite Decking Cost?

The cost of composite decking varies depending on the quality and style. Ecoscape offers three composite decking collections.

The Clarity composite decking board collection is the cheapest option. It’s made from recycled HDPE and reclaimed wood fibres and costs just £41.55 per square metre.

The Forma collection offers the same high-quality composite decking with additional protection. The boards are wrapped in durable HDPE and offer greater scratch resistance and protection from fading. The Forma range costs £66.12 per square metre.

The most expensive composite decking board collection at Ecoscape is the Grande range. The boards are the same quality and specifications as the Forma range but are 50% wider. They cost £69.58 per square metre.

Can I Calculate My Substructure And Supports In A Decking Calculator?

Decks require high-quality substructures and support to last. Preparing the ground before installing your substructure is essential.

Our calculator gives customers peace of mind. This is because you can calculate the required material quantity to create a safe and secure decking area.

As well as letting you know how many decking boards are required, your substructure and support needs are also met.

You will have the option of selecting a plastic or aluminium joist, which will need to be supported with either a pedestal or plastic posts. The size of the joist will determine how often a support is needed – the span is calculated. The calculator will estimate how many joists and posts are needed.

Which Way Can I Lay Decking

Knowing which way to lay your boards is important, and the options at Ecoscape are reversible, meaning you can choose the style you want.

The laying direction will also determine the material needed and may affect costs. Most people lay decking horizontally or vertically. These are the easiest options and can work well on flat ground with a minimal incline to help with water run-off.

Laying your decking at a diagonal angle is also possible, and this is all accounted for in our calculator. Laying your deck diagonally will create more waste, so adding 10-15% to the estimate is advisable.

Choosing the correct length of deck board is important if you want a deck to have no joints. This is another option in the calculator. Please note that you can choose various decking lengths and widths to create the right look for your project.

Will the decking calculator quantify fascia boards?

Our composite decking calculator will calculate the fascia boards or decking boards required for any project. By adding in the finish floor height (FFL), our calculations will produce a material list of what is needed, it will also calculate the number of colour coded screws.

What Is The Best Way To Plan My Decking Project?

When planning out your deck you can start off with a bit of paper and some measurements. This will give you a better idea of the space you have to work with. You should also take into account how the sun moves around your garden as the day progresses.

As you get a better idea of what you want, online deck planners and visualizers can be used to see what the project would actually look like. This can help you choose colour schemes and the correct size or shape for the space available.

Will the decking calculator supply a drawing?

At the end of the calculator, you can download an estimate. Along with the quote, you will receive a diagram showing both the substructure and decking layout. The quote will detail the number and lengths of boards, along with t-clips, locking clips, screws, etc, needed for the project.


Are decking calculators free to use?

The Ecoscape decking calculator is completely free for anyone to use.

How accurate are decking calculators?

Decking calculators are only as accurate as the information they are provided with. Always double-check your measurements and consult a professional if you have any doubts.

Do I have to use a decking calculator?

You don’t have to use decking calculators before you start your project. However, you should ensure you have the correct amount of materials to safely build your deck.

Final Thoughts

Decking projects can be complicated before you even get to complete the installation. That’s why it’s important that you get your measurements and material requirements right before you get started.

The Ecoscape decking calculator is a valuable planning tool that helps you make calculations to minimise waste and reduce costs.

As well as meeting your decking board needs, our calculator can also help with fascia boards, joists, and much more.

If you have any other questions about your decking, please get in touch, and we will answer any queries you have.

Please note that the Ecoscape decking calculator is to be used as a guide only, we advise that you check the quantities on your estimate before placing an order to make sure all calculations are correct.

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.