Things You'll Need:
- A straight 2x4, a tape measure, pencil, and 10" nails, and a 2 foot, or torpedo level.
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Step 1
First, determine where the center of the door is by measuring the width, and dividing that in half. Next, level down with a two foot, or torpedo level, to the ground and set a nail. based on the size of your deck, measure over to the right from the center nail, half the length and set another nail. from there, use your straight 2x4 (at least ten feet long)and place it next to the second nail, making sure that it is flat against the foundation.
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Step 2
Now you are ready to use the 3-4-5 rule to make sure that your deck will be square. Measure over to the left from the second nail three feet and mark the foundation. then measure up the 2x4 four feet and mark the board at four feet. then measure between the four foot and three marks until you get five feet between them. now you are square with your house, and ready to mark your post holes.
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Step 3
Depending on the size of your deck (for example, a 10x12) measure out from the house eight feet and mark the board. This is how far out from the house the posts will be. (on a 10x12 deck) Measure over to the left from the eight foot mark, two feet and set another nail, this is your first of two posts. Next, measure over another eight feet and set another nail. then measure out from the house to make sure that your nails is eight feet out as well as eight feet over. Now you have marked your post holes for your deck. They will be two feet from the end and sides, giving your deck the proper support.
