A family that recently moved to Bismarck was looking to upgrade their deck to improve safety and help prevent future damage due to the elements. The primary safety concern was that the existing beam (or girder) was simply connected to 4” x 4” support posts with carriage bolts; not sitting on top of a notch-out in the posts. The posts were also sitting on standard anchors, which did not allow for water to drain away from the base of the post and rotting was apparent in one of them.

Another significant concern was that the ledger board was secured to the house with standard deck screws only – no lag screws were used in securing the board to the house.

And finally, the original deck construction did not include flashing above the ledger board to prevent water from seeping into the space between the board and the house.

I began the project by installing a temporary 4” x 4” support post under the beam next to an existing post, after which the old post was removed. Anchors with elevated plates were then secured to existing footings with compression bolt anchors. The installation of 6” x 6” treated posts allowed for notching the post enough for adding pressure-treated 2” x 10” boards to the back of the beam and two of the three beam members to rest on top of the post notch-out. Securing the beam to the part of the post not removed for the notch-out are 6” lag screws. The process was repeated for the remaining posts.

The three rows included in the beam were drawn together with carriage bolts and 3-1/2” deck screws to secure the beam as one unit. Lag screws were sunk into the ledger board approximately every 16 inches and deck boards were temporarily removed for installation of flashing on top of the ledger board along the wall of the house.