Expert: Stephen Major (Owner--Major Design Group) - 8/13/2007

Question
I'm working on a project where I pointed out 3 footings supporting two story 40'x20' decks are heading downhill. My concerns are relating to the support for the structure before removing/replacing each footing. The decks are 2x10 pt w/ 6x6 posts at each level and 6x6 posts to the eave that spans 15' from the house. No Strong Ties, no cross/lateral bracing, 2x6 decking supporting post above at each level. Not only was the structure poorly built, its alot of weight on the base posts and footings!
The first level is 20' above grade and the grade is about 30 degree. I've piled r/r ties in a 5'x5' platform behind the initial post I want to remove. My question is; Do I need more support to hold this securely, should I support the entire structure? I have braced the other posts to minimize lateral movement but I am a little on edge due to the nature of this failure in a home less than 10 yrs old. I don't want the repair initiating or accelerating the failure so any insight would be greatly appreciated

Answer
Mark,

Thanks for sending the photos.  I would install a temporary post on BOTH sides of each footing, and replace them one by one right down the line.  

The 6x6 posts are probably adequate in compression, but they are in need of permanent lateral bracing in both directions.   Once replaced, you should consider adding substantial diagonal bracing across the front plane as well as beneath the deck, to prevent the middle portions of the posts from flexing under load, and to stiffen the support structure in general.  Perhaps doubled 2x8s or similar.

The footings should be sunk well into the soil, and have wide bases, to prevent overturn.  Secure the posts to the footing columns with adequately sized Simpson or similar anchors.  Also, be sure the tops of the wood posts are well secured to the deck.

Best of luck with this challenging project.

--Steve Major




Mark,

Unfortunately I really need to see photos of this structure (near and far) to evaluate and advise. If possible please send them via e-mail to:
info@majordesigngroup.com

Thanks,

Steve Major