More On Deck Safety
I recently completed some work on a deck that serves as a good follow up to the previous post, Improving Deck Safety. The homeowners are in the process of selling and the deck was flagged by an inspector for the stability of the deck stairs. In looking at the stairs in order to provide an estimate, I discovered several other errors in the original construction that will need to be addressed, either by the current owners or the next ones.
The estimate provided – and work performed – covered simply the immediate concerns identified by the inspector, namely stair stability. I constructed under-stair bracing to help limit lateral movement of the stairs as well as provide additional support for the long stringers. The bracing consists of 4” x 4” pressure-treated posts anchored in concrete deck block with 2” x 6” pressure-treated boards comprising the lateral connection. While the bracing resolved much of what the inspector noted, below are additional deck errors that should be addressed prior to substantial use.
While the new under-stair bracing provides stability to the stairs themselves, the railings the original deck builder installed on the stairs and deck itself are less than adequate. The railing consists of only 2” x 2” spindles for support, with no anchor posts installed. According to general guidelines, 4” x 4” posts must be included every 6’ on deck railings, and every 5-1/2’ on stair runs. With the current construction, the railing provides very little in terms of resistance to lateral forces that may move against the railing. Around Bismarck and Mandan, there are probably more decks than not with this deficiency.
Bismarck deck railing requirements
An additional error made in original construction was the omission of anchoring between the stair stringers and the concrete landing of the patio. This often includes blocking between the stringers or a treated 2” x 4” notched into the base of the stringers, or at the least, angle brackets secured to both the stringers and the concrete pad.
Other deck errors I identified are no less concerning and likely more critical to overall safety. While current code requires beams to rest on top of support posts, with the post notched for securing the beam to the post, several of the support posts were attached to the rim joists simply with deck screws. A fairly quick, inexpensive fix would be to install carriage bolts through the joists and posts. This wouldn’t be to code “to the letter” so to speak, but would provide additional security.
One of the joists was resting on a support post, though the connection was made with deck screws only, and no post material remained for the joist to attach to laterally. I installed a top-of-post bracket to provide some further lateral support – not ideal, but a “make do” within the approved scope of the project.
Minor deck errors are common and to be expected. When the errors affect the overall safety of a deck, they need to be addressed in a timely manner. Following is a link to another post regarding deck safety from the Journal of Light Construction: Common Deck Defects.