# How Much Composite Decking Do You Need?

If you’re wondering “How much **composite decking** do you need?”, then you’ve come to the right place. These steps will give you a workable estimate, and they work best for outdoor decks with rectangular or square layouts.

Table of Contents

## How to Calculate How Much Deck You Need: a Step-by-Step Guide

- Step 1: Calculate the area of the deck in square feet.
- Step 2: Select the length of composite decking boards to be used.
- Step 3: Find the area of the boards.
- Step 4: Divide the area of the composite decking boards by the area of the deck.
- Step 5: Find the square footage of sturdiness between the decking boards.
- Step 6: Consider accidents, losses, and cutbacks.

## Step 1: Determine the Size of the Deck

To answer the question, “How do I figure out how many deck boards I need?” To answer this question, you must first calculate the square footage of the deck by multiplying the length of the deck by the width (length x width).

If the deck is 16 feet long and 12 feet wide, multiply 16 by 12. This gives you 192 square feet, which is the area of the deck.

If your outdoor deck has multiple decks of different sizes, you simply add up the areas of all the decks to get the largest deck.

Don’t forget the **deck stairs**. If your deck has stairs, you need to calculate its area as well. To calculate the total area, first multiply the length and width of each step. Then add the area of each step to the area with the deck and finally get the total area of your outdoor deck.

## Step 2: Select the Length of Boards to be Used

**EVODEK**‘s composite decking boards come in lengths of 12 feet, 16 feet, or 20 feet wide.

If you have a large deck, you may want to buy the largest composite decking boards. but this is not always the best choice. For example, two 12-foot boards will fit a 24-foot deck better than 20-foot boards.

Consider how each length of composite decking boards will fit into the deck framing and whether each board will need to be cut. Keep in mind that the fewer decking boards you have to cut, the better.

Factors that influence which board length is best for a deck project include:

**The size and shape of the deck**. Consider the size and shape of the deck, then choose the length of planks that will fit the deck framing.**The way the planks are laid**. Depending on the way you lay the composite decking boards, they may or may not be suitable for your deck framing. You can lay composite decking boards straight, diagonally, or in a more complicated way.**Picture frames**. Do you have picture frames on your outdoor deck? If so, consider the edges of the picture frame when choosing the length of your composite decking boards.

## Step 3: Calculate the Size of the Decking Board Area

After selecting the length of composite decking boards to use, find the square footage of the boards. This will help you answer the question “How do I figure out how many composite decking boards I need?” To do this, you can multiply the length of the composite decking by the width.

Make sure to change the length of all the boards to feet before calculating.

Example: Let’s say you chose regular-width composite decking boards that are 16 ft. long. First, divide the width (5.5 in.) by 12 in. to get 0.45 ft. The area of the boards is 7.33 square feet, or 0.45 feet times 16 feet.

## Step 4: Divide the Square Footage of the Deck by the Square Footage of the Planks

In step 1, we calculated the total square footage of the outdoor deck that needs to be built. Then in step 3, we calculated the square footage of a sheet of composite decking boards. Use the total area of the outdoor deck divided by the area of a single decking board to get the exact number of composite decking boards needed.

Example: In the previous steps, we gave an example of a deck with a total area of 192 flat feet. The area of one composite decking board is 7.33 square feet. Dividing 192 square feet by 7.33 square feet gives us 26.19, which means we need 27 composite decking boards.

Note that when the calculation is not a whole number, you need to add numbers to get a whole number, and that number is the number of composite decking boards you need.

## Step 5: Calculate the square footage of decking board spacing

This is the total square footage obtained by adding up the spaces between all the decking boards that cover the area.

So, how should we calculate the square footage of decking board spacing?

EVODEK composite decking boards should have at least 1/8 inch spacing between each board, but the exact spacing will change depending on the type of deck boards and the fixtures you use.

To use board spacing in your material calculations, figure out the minimum positions you may need to consider. This will ensure that you have enough decking material.

To calculate the spacing, multiply 0.125 (1/8) inch by the number of boards on the deck (n) and subtract 2. This is because there will be no gap between the first and last boards on one side.

In other words, the formula for calculating deck board spacing is: Spacing (S) = 0.125 x (n-2)

Example: You found 27 boards (n) in step 4. This means you need to take 27 – 2 to get 25, then multiply 0.125 by 25 to get 3.125 inches.

How to calculate square feet for plank spacing: To calculate square feet for plank spacing, start by increasing the spacing (S) with the length of the deck. Change inches to feet before calculating.

Square feet between boards = (S) x deck length

Example: The spacing between each row in the previous formula is 3.125 inches, and the length of the example deck is 16 feet. First, divide 3.125 by 12 to convert inches to feet. This yields 0.26 feet. Then, multiply 0.26 feet by 16 feet to get 4.16 square feet, which is the amount of space between boards.

If the space between the planks is larger than the area of one or more planks, you may not need to buy an extra plank or two. In the example case in this article, 4.16 square feet is less than the 7.33 square feet of a piece of composite decking boards. So you still need to buy 27 composite decking boards going into step six.

## Step 6: Consider Accidents, Losses, and Cuts

When you ask yourself, “How can I figure out how many decking boards I need?” When it comes to being safe, it’s best to have a few extra boards on hand. Even the most skilled DIYers can run into problems. You might miss a cut, put a screw in the wrong place, and so on.

To be on the safe side, add at least 10 to 15 percent to the number of composite decking boards needed to account for mistakes, waste, and extra boards.

In Step 5, you confirmed that you need 27 composite decking boards to complete the project. To add 10%, multiply 27 by 1.1 to get 29.7. It is best to round up to 30 boards. To give yourself a little more room, multiply 27 by 1.15 to get 31.05 and round up to 32 boards.

If you’re laying composite decking diagonally or in a more complex pattern like a zigzag, you’ll have 10-15% more scrap.

Measure twice, and cut once. Make a list of the things that will affect you the most. This will help ensure that your imagination meets your and your family’s needs.

## Other Decorative Materials to Consider

If you’re wondering how to figure out how many composite decking boards you’ll need, that’s not the only question you should ask. Building an outdoor deck requires more than just decking boards. Make sure you purchase other things you may need, such as:

**l Hardware**. Fasteners and screws are the tools needed to build a deck. How many fasteners you need depends on the size of the composite decking and the type of fasteners you use.

**l Fascia boards**. Fascia boards run parallel to the ground to hide end cuts and give the deck a flat, smooth look. How much fascia you need depends on the length of the deck edge.

**l Joist Tape**. Applying joist tape to the top of the joists protects the foundation from water damage. How much joist tape you need depends on the number and length of the joists.

## Conclusion

Now you know how to calculate how much lumber you need. Now you can start budgeting for the purchase of composite decking boards. If you have more questions, please contact us. EVODEK has a professional service team to answer your questions.

In addition, we will provide you with free samples of composite decking. This way, you can have a better idea of the deck color and model you choose before you officially build composite decking.