Squaring Up A Deck Frame

The single most important framing member is the ledger board.

Squaring up a deck frame.

If the measurements match your frame is square. Using a square and a 4 level will also help verify that your deck form is level. One way this old house general contractor tom silva ensures that mason s strings and deck framing are square when he is building a deck is by employing the 3 4 5 rule based on the pythagorean theorem. Compare the opposite lengths of the perimeter of squares and rectangle forms these lengths should be the same.

If they don t push the two corners that are further away the long measurement back together a little and remeasure. A common mistake with diy ers is to forget to square the frame up or box. The foundation of a deck that rests on posts should be properly laid out which involves making sure the posts are square. Some guys gals prefer to use the 3 4 5 method or the cross over method i use both.

Obviously the more square the frame the better. This is a crucial step that must be taken when building a house or when framing a simple deck. Once installed it acts as a guide for a deck frame that s level and square. Slight tolerances can be adjusted before the joists are installed to prevent exaggeration.

First he tacks a double joist hanger to one end of the ledger and slips a side rim joist into place. Anyone wants to learn the way to square a deck should know the 3 4 5 method as many builders often use it to make sure they are building a square deck. 3 4 5 rule to ensure square layouts. Then he marks the top of the ledger 3 feet from the corner and the top of the side rim.

Measure again before and after your first deck board is installed and every few boards as well to ensure it stays square while building. It s a good idea to mark joist locations on the ledger and on the front facing rim joist before installation when you can lay the framing members side by side on a pair of sawhorses. As with all structures a long lasting durable and solid deck depends on a proper foundation.