What’s the Right Gap Between Deck Boards?

There is a lot you need to consider when installing decking. Which direction to lay the deck boards? Are you having grooved or smooth decking? What timber species is right for your purpose? Most of these are particular to your project, so we recommend speaking to your local timber merchant or landscape contractor. Fortunately, if you’re wondering whether to leave a gap between your deck boards, there is a very straightforward right answer.

Should You Leave a Gap Between Decking Boards?

Without a doubt, you should leave a gap between your decking boards. This is vital to the success of your decking and improving its durability. If you don’t leave a gap, you are opening up your project to a whole wealth of future issues. 

What’s the Purpose of Leaving a Gap?

Wood is made up of many fibres, and these fibres are able to absorb and retain moisture. The more moisture in the wood, the more it will expand. When the moisture decreases again, the timber will again contract. This means that your boards are constantly ‘breathing’ and moving. A gap allows them to expand and contract without an issue, making sure your decking can survive winter and summer, and the ever-changing levels of humidity in the air. 

If you don’t leave a gap, your boards can become damaged as they swell and grind against each other, or as they shrink they may leave gaps that are too large and make your deck unsafe to walk on. 

What Gap Should You Leave Between Decking Boards?

The size of the gap you leave should be between one quarter to one eighth of an inch (6.35mm to 3.175mm). If you’re installing the decking yourself, you can use something for reference to ensure the gap is consistent across your surface. 

So, one quarter of an inch or one eighth of an inch – which should you choose? The answer comes down to a number of factors. For example, if you’re using a composite, you can usually put a narrower gap between boards as it will shrink less than wood. If you’re installing your decks in summer on a warm day, they are usually less swollen than during winter, so you can leave a bigger gap here. We don’t recommend going any more than 10mm. 

As soon as your wood gets outside, the humidity and temperature are going to cause it to swell or shrink, depending on the moisture in your deck boards. If you can, it’s a great idea to leave the boards in place for a week or so before you install them, giving them time to acclimatise. Just make sure it’s not sitting directly on the ground so that it doesn’t soak up water!

Get Help Working Out the Perfect Spacing For Your Decking

If you’re not entirely sure what size gaps you need, our team at EcoChoice are here to help. When it comes to sustainable timber and decking, we’re the experts. Reach out to our team today and let us know your question. We look forward to hearing from you!

Image: ronstik / Shutterstock.com



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