Decking Calculator
Use this handy calculator to show the quantity of deck boards required.
Frequently Asked Questions
How do I calculate how much decking I need?
To calculate how much decking you need, first measure the length and width of the area where you plan on installing your new decking. Then, multiply these dimensions to determine the total area in square metres. For example, if the area is 5 metres long and 3 metres wide, the total area would be 15 square metres. To account for cuts and waste, add about 10% to this total area to ensure you have enough material.
How many metres of decking do I need?
The amount of decking required in metres depends on the dimensions of your deck boards and the total area to be covered. First, measure the area that is to be decked in square metres (length x width). Next, determine the coverage area of each decking board and divide the total area by this coverage. To determine the coverage for each board, take the board’s width in mm / 1000 and multiply this by the board’s length in mm / 1000. For example, if each board covers 0.5 square metres and you need 15 square metres, you will need 30 boards.
How do you calculate how much decking you need?
Calculate how much decking you need by measuring the length and width of the area that you want to cover with decking, then multiply these dimensions to get the total area in square metres. Determine the area covered by one deck board and divide the total area by this coverage. Remember to add around 10% extra to account for cuts and wastage.
How do I work out how much decking I need?
To work out how much decking you need, measure the area to be covered (length x width) to find the total area in square metres. Determine the coverage of each decking board [(width in mm / 1000) x (length in mm / 1000)] and divide the total area by this coverage. It’s also a good idea to add about 10% extra to accommodate for cuts and wastage.
What is the minimum gap under decking?
The minimum airflow gap under decking is at least 50mm for ventilation. This gap allows for proper airflow and drainage, reducing the risk of moisture buildup and rot.
Do you need a membrane under decking?
A membrane under decking is not always required, but we recommend covering the ground with a permeable membrane and retaining the sheet with a 50mm layer of gravel. This is helpful in preventing weed growth and protecting against moisture damage. It is particularly useful in areas prone to high moisture or where maintaining a clean space underneath is desired. Decking should be laid on UC4 incised joists when in ground contact.
Can you lay decking without gaps?
No, laying decking without gaps is not advisable. Gaps between decking boards are important for water drainage and air circulation, which help prevent moisture damage and rot. A gap of 5-8mm between adjacent boards, 5mm where the board abuts a post and 2mm at board ends is recommended.
Do you need gravel under decking?
Gravel under decking is not mandatory but can be beneficial. It improves drainage and prevents weed growth, helping to keep the area underneath the deck dry and reducing the risk of rot. We recommend covering the ground with a permeable membrane and retaining the sheet with a 50mm layer of gravel. Decking should be laid on UC4 incised joists when in ground contact.
