Stair railing post spacing in Ontario
(Kemptville, Ontario, Canada)
I am just finishing up the railing on my deck.
I have a 42" high wood railing with 2x4 bottom rail 3.5" off deck with wood 2x2's attached to outside of 2x4. And a top rail 2x4 with a 2x4 top plate to cap it off.
I am trying to match the same style for my stair rail.
I have a post at top of stair and one at the bottom of the stairs. Both of them are anchored into the foundation.
The span is 5'. Most drawings I can find say 4' is maximum span but I have seen 100's of decks with a lot bigger span then 4' that have passed inspection.
I have poured through the building code and looked for it but there is nothing to specificly address this issue, both posts are solid like a rock.
Ontario has it's own appendix to the building code. It's called SB-7 Guidelines
and what it essentially does is set out a number of axiomatic drawings of many different kinds of wood deck railings that if you build just like the picture any inspector is obliged to approve.
Many different ways of building are always allowed so long as you can prove that their performance will meet or exceed the minimum load values in the code.
So just because you don't match one of the drawings its the end performance that matters.
Now you have stair railing posts at 5' apart. I do not recall ever seeing anything mandating the can not be 5' apart. However, for the main railing on the deck I have seen references to some of the axiomatic drawings between 4' and 6'.
Keep in mind that is only if you build it exactly as shown in those drawings.
That is why manufacturers go to great lengths to get some test data done using their railing products so they can say they do indeed meet the minimum standards.
In your case, if an inspector is coming because this is a new build or because you went to the city and got a permit, then you will have to either show a) you built them as per SB-7 drawing; b) you have had an engineer sign off on it; or c) your inspector is fine taking a close look and giving it his own on site "push" test.Practically Speaking
Since you set the bottom newel post into concrete there is no way that is going anywhere. The design point load in Ontario is 224 lbs (1.0 kN) and a safety factor is based on its mode of failure which is likely a slow failure. So safety factor is 1.68x (based on my own experience working with Intertek Engineering Labs).
And you know, this is just my editorial commentary, I do find this a bit of a perfect example of how our inspectors in many cases simply do not exercise any professional judgment.
This is either because they don't have any experience building in real life. This I have seen first hand. Or the city is so law suit focused they may as well remove any human being from the equation and have a robot stamp a form.
You are going to be fine...