When building steps for a deck, is there a standard distance formula for how far to span your wood when building steps? We have a deck built 10 feet off the ground with 2x6 wooden steps that have a huge span. Something around 4 feet. When you step on these steps they visibly bend and I know that will lead to problems in the future.
Are their any regulations or building codes regarding such things?
I live in Washington State.
Thanks in advance for any help.
There is code that directs this, but I couldn’t tell you where to look. From my experience (college summers working for a deck contractor) using 2/6’s you should have three risers, the middle one in effect less than 24 inches from the outside ones. Using the 5/4 round stuff which is popular now, we’d use four risers, basically centered on 16’s.
There are definitely codes – you should (must) check with your local building inspector. For some reason, decks seems to be heavily regulated (possibly they’ve had a lot of poorly constructed ones collapse).
From my brief reading of some typical codes, it looks like you have a couple of sources of concern. The first is that the typical tread depth seems to be 10 inches, not six. The second is that the maximum span for a 2x6 used as * decking * is between 2 1/2 to 3 feet, depending on the grade of the wood.
Anyway, your best bet is to add a third set of supports in the middle of the steps in order to take up the load.
I’m at home right now so I don’t have all my code books at hand but my general rule of thumb for deck stairs is an ideal slope of 7" rise to 10-1/2"tread. With a 10’ rise, you would get 16 steps @7.5’ run. Assuming a 10-1/2" tread, thats about an 11’ deep stairway! For a stairway like that, I’d do 16" o.c. I generally overbuild but I get very few complaints 
There is nothing worse than going up a flight of stairs and not feeling absolutely rock solid - especially in icy conditions. Speaking of icy, think about putting grip strips in the treads for the winter and rain, I’m sure it gets a bit nasty up in WA. I rout a 7/8" recess and insert metal strips with the pebbly grey nonskid stuff on them. It’s easy to set up and looks really well done when it’s in.
You mentioned using 2x6’s as your treads, as the other poster mentioned, 5-1/2" minus your 1"overhang and 3/4" where the risers rest on the back of the treads gives you an extremely steep rise. I prefer an even wider tread as then it is more comfortable for general use/sitting on with friends and a beer/kids etc. Of course this is dependent whether you have the landing space for the increased stair area. If you don’t have that kind of length, I’d seriously consider talking to someone about turing halfway down. A lot of the building centers have computerized planning systems that will layout your deck, give you a complete bill of materials and the guys generally know what they are doing ( HINT: go to a contractors supply house, not HomeDepot et. al.)
Yes, I generally overbuild but I get very few complaints
DISCLAIMER!!!
I build in IL, my experience is with the local inspectors in the 8-10 communities I work in regularly and should in NO WAY BE CONSTRUED as or relied on for engineering or structural planning.
Spend the 50-100 bucks to get your plan signed off on by a structural engineer if you don’t go to a center. In fact your municipal Bldg Dept. may require it. Another reason to go to a contractors place is that these plans they give will usually get sped right through the bldg dept. It’s amazing what a professional looking printout will do to a harried inspector:)
I have reconstructed two decks which fell down due to homeowner incompetence; one of which resulted in a fairly bad injury (compound fracture IIRC)
I’m sure I’m forgetting something but enjoy the project and remember; measure twice, cut once!
D’oh!
…16" o.c AND an intermediary set of posts…
Check your state and local codes before starting any project. Follow all safety precautions. Every effort has been made to ensure accuracy and safety. Neither MikeG, any contributor nor the supplier can be held responsible for damages or injuries resulting from the use of the information in this document.
(Sorry, I was sued once and I just C&P’ed this from my boilerplate)
[sub]Yes, it can be that serious[/sub]