Things You'll Need:
- Tape measure
- Wooden stakes
- Mallet to drive stakes
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Step 1
Measure out the size of the deck and place wooden stakes at the corners of the deck. This will let you visualize the exact size and placement of the finished deck. Make sure that the stakes are placed so that the deck is square at all corners.
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Step 2
Determine the distance from the corner closest to the house to the extent of that side away from the house. This measurement will form the beam for the outer edge of the deck. Also measure the length of the other sides of the deck.
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Step 3
Calculate the number of support posts that will be placed along each direction of the sides of the deck. Select an even number of posts to be placed along each side of the deck. Common deck support spacings are 12, 18 and 24 inches.
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Step 4
Space your joists either 12 or 18 inches apart. The smaller the spacing the stronger the deck floor will be. Once you have figured out the spacing of the joists you can calculate the deck span.
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Step 5
Go to the online span calculator at planhelp.com (See Resources). Enter the figures for the type of wood, spacing of joists, load limits and deflection limits. Select the Calculate Span Options button and read the span sizes that are recommended for your deck.
