DISCOVER

# How to calculate the cost of a deck

Updated July 19, 2017

The addition of a deck to any property is an effective means of improving your living space and increasing the value of your home. Decks serve as welcome outdoor areas for entertaining or relaxing. They may also surround your pool, opening up the area for greater enjoyment. Building a deck is an expensive undertaking. Before beginning the project you can easily calculate the cost of materials, and labour if you don't plan to build the deck yourself.

Measure the length and width of the deck you plan to build. Multiply these two numbers to get the area of the deck surface. To save money, try to make the length or width equal to a multiple of common decking lumber sizes -- 8, 10, 12 or 14 feet. Determine how many pieces of decking lumber you'll need, and make a notation of this figure.

Measure the height of your deck if it is to be raised, and if necessary, the number of stairs required. If the deck will be raised, determine how many 4-by-4-inch posts are required. Posts should be placed no more than 8 feet apart, and in each corner. Make a notation of this figure. If the deck will not be raised, there is no need for posts.

Add concrete footings to the base of each post. Write down this figure.

Add one 2-by-6-inch beam to span the distance between each set of posts. For example, if there are three posts per side of the deck you'll need three beams. The length of the beam is determined by your deck surface size. Note the number of beams required.

Place 2-by-6-inch joists across the beams every 18 inches. Determine how many joists are required, and note this figure.

Add two stringers if there will be stairs. Based on the width of the stairs, determine how much decking lumber is needed for the tread of each step. If a railing will be used, add the materials for the top rails, typically a two-by-four; the posts, usually four-by-fours; and a vertical baluster between the posts, also usually made of two-by-fours. Note these materials.

Add hardware according to the number of joists and beams you have, such as, two joist hangers per joist and proper screws or nails, and 3-inch lag screws to attach beams and posts. Use two decking screws for every joist the decking lumber sits upon. When calculating hardware, add 10 per cent more materials than your total. You can always return unused items.

Call your local hardware store, or better yet, go to the store yourself. Note costs of items according to your list. Be aware of the different types and costs of decking lumber. Use a calculator to figure your total cost. Additionally, you can use many of the online calculating programs available to figure your deck costs.

Call local contractors for estimates on labour if you don't intend to build the deck yourself. Get estimates from three contractors in order to obtain the most accurate going rate.

#### Tip

You can purchase deck plans to make the job easier and more predictable.