Deck-stair newel post… anchoring?
Just about to frame up two sets of stairs from a deck. Both descend to grade. The stairs are fairly typical: 2×12 stringers, ipe treads and risers. The deck posts are 4×4 PT wrapped in 1x cedar. I’m thinking about how I’m going to anchor the newel posts at the bottom of each stair solidly. I do not want to cast the posts right into concrete like fence posts, because they’ll rot out sooner than I can stand to replace them. Here are three ideas I had:
1) Pour a small grade beam at the bottom of each stair, and embed a Simpson CBQ column base for each 4×4. Anchor the posts in the CBQs, anchor the outside stringers to the posts, and wrap the posts. The posts and grade beam would form a sort of ‘U’ shape and the hardware would give the posts a lot of stiffness. I know that Simpson says ‘not for non-top-supported applications’
2) Solid block with 4×6 between the stringers at the bottom, and then run all-thread horizontally all the way thru the posts with a nut and washer on each end. This would let me compress the whole assembly quite a bit and lock the posts in.
3) Use someone else’s method. How do you typically do this?
Replies
I sort of got this idea from TOH, but there it was inside with wood floors and so on, but I still think it would work: Make the newel posts hollow (1 x 4's) with a square wooden "plug" near the top. Pour the grade beam you talked about and imbed a bolt that will you will later splice the all-thread to using one of those deep nuts. Put the post in, poking the end of the all thread up through a hole in the plug in the newel post and use a washer and nut to tighten. Then glue on the decorative top of the post.
I know what you mean about imbedding posts in concrete. I have nothing nice to say about that method. The allthread rod idea sound kind of neat, but is all-thread available in HD galvanized?
Attached is a pic of a detail I like to use on the bottom riser/step/newel post. Works well, especially if the bottom of the post is stabilized by an anchor bolt poured into concrete after the steps are built or similar - I'm guessing the simpson bracket would do the same thing, although I'm not familiar with that exact one. In the pic concrete slab was existing...
dave.. if they are PT.. we always bury the post and tamp gravel around it.. then we bolt the post to the stringer..
the treads stabilize the stringer.. and the 30" of bury stabilize the post..
they never rot out ( well not yet , anyway.. )..
then you can wrap all the above ground with your cedar
Here's what I decided to do... two pics. I temped up the outside stringers so that I'd know where to put the hardware. All those clamps and other mess are there to hold the hardware in place until the mud sets up a little.
Still not sure if I'm comfortable installing ACQ posts into those galv post bases and then wrapping them out of sight. Might buy some cedar 4x4 for that.
The lower section of the slab, the landing, will be brick reused from the chimneys we tore down. I'm gonna show my wife how to mix mortar and set brick, let her have at it!