How to Use Shared Load Deck Support Posts
It if often practical to use a common post and footing to support two or more beams in a deck design. This usually happens in multilevel decks where a lower deck intersects with an upper deck along a line of posts and footings. Stair landings that wrap around the frame of a deck often take advantage of sharing a corner post.
Although this can be a great technique for reducing your quantity of footings for your project you must be careful to consider the types of compound forces you will be exerting on the post. A beam attached to the side of a post will be pulling out and down away from the post. You must maintain a minimum 1-1/2" beam bearing ontop of a post. In order to satisfy this requirement you will need to create a notch in the lower section of the post. Installing a cleat along the post below the beam can provide added stability and increased support.
Consider how large amounts of load applied from the side coupled with the downward force of the higher beam can overload the capacity for the post and don’t forget to adjust your footing size to accommodate the additional loading. Be sure to use the proper type and quantity of fasteners to prevent them from shearing off under the load. Using long ½” carriage bolts will work well in this application. Check with your building inspector.
Comments & QuestionsAdd New Comment
I'm building a 2 level deck with a roof over the upper deck (14'x12'). The lower deck (12'x12') is 2 steps down from the upper deck. I have 3 - 6x6 posts that will be shared load between the upper and lower decks flush beams with joist hangers, and was planning on notching something like you show here, except that the 2 outer 6x6 posts will also be acting as the roof support. My thought is to notch only 1.5" for half of the beams for both upper and lower, with a notch at the outside corners of the posts to allow for the rim joist to also rest on the post. My concern is that I'm removing too much meat from those posts. Wish I could post a picture here..
David C - 5/24/2016 8:05:21 PM - replyShow 1 Replies
When building a deck with a pergola similar to your Plan 1LX2324, should the 6x6 posts of the pergola also support the floor structure and extend down and attach to the footings similar to the shared load deck support method you show here? Or instead do you recommend keeping these supports separate and simply attaching the 6x6 support posts of the pergola to the top of the deck floor only (with deck supports)? Thank you.
Howard B - 12/12/2016 1:47:44 PM - replyShow 1 Replies