Step 1 Measure the Deck
Measure between the outside of the header joist and the house at the top of the ledger. Do this at the centre and ends of the deck to determine whether the distances are equal. Mark each rim joist at a distance from the outside of the header joist equal to the width of one decking board. Make these marks at equal distances from the house. Note: Decking installation also can begin at the house with the final board attached to the header joist.