I am planning on nailing down solid Bamboo on the second floor of my home. I have a "catwalk" hallway in my second floor that looks down on the first floor on both sides of the catwalk (see photo in url at the end of post). This means that I do not have walls on this catwalk. If I had walls I could hide the 1/2" spacer gap required for this type of floor by installing baseboards on the wall but this catwalk does not have walls so I cant hide the spacer gap with baseboard. I would rather not have 1/2" spacer gaps left open on either side of of my catwalk hallway once installation is complete. I would also rather not completely redo the catwalk railing if possible. How should I proceed with installing the floor on this catwalk given the required 1/2" spacer gap? https://dl.dropboxusercontent.com/u/25725705/20161105_123309.jpg

How thick is the railing base? How thick is the bamboo flooring? If railing base is thicker you could undercut it for the expansion space. Or shoe molding/quarter round along the edge of the railing base to hide the expansion gap.

The railing base is 3/4 in thick and the bamboo flooring is 1/2 in thick (stranded bamboo with hand scraped finish). I have considered routing underneath the railing base. The tough part would be laying the for the last row of flooring on the cat walk and trying to make the wood fit under the routed gap. Any suggestions here?

Not sure how good shoe molding/quarter round would look good since the railing base is beveled but I guess I can caulk in between the railing base and shoe molding/quarter round if I go down that route.

Thanks for your inputs.

You can slide the last row boards from the end of the catwalk and push them toward the other end catwalk. To avoid a long push you could install some of them before the second to last row is installed and then pull them back toward the second to last row.....if you do this initially leave spaces between the ends of the last row boards so you can get a grip on them.
The shoe molding/quarter round could be beveled to match the base molding bevel to create a tight joint.
Not easy but doable.

Those are some great ideas, extremely helpful! Thank you!

My personal opinion, too many overthink situations like this. Yep, it's bamboo, but is it that unpredictable NOT to net fit the area? Never it my days of installing floors did I ever think otherwise. I would have been thrown off a job if I ever considered trim in that area. I've even seen 40 and 50 year old floors tight to brick and stone without any ill effects.

So what's going on these days? Is it the fear of all this imported craploa that's causing problems? My inquiring mind is inquiring.

I saw on another forum that the direction you will be laying the flooring on the catwalk will NOT be like a bowling alley. If this is so, then undercutting the railing base for the expansion gap and getting the ends of your bamboo flooring should be fairly easy.....I had been assuming that you would be laying the bamboo on the catwalk in a bowling alley layout.

I'll be laying them parallel to the white railing base.

That's what I originally assumed. If you are standing at either end of the catwalk the boards will run the way they do as if you were standing at the foul line of a bowling alley? When I saw 'parallel to the hallway' (other forum) I wasn't sure.

This seems to be a hot topic. The best solution is to buy a jamb saw and cut a "rabbet" or a gap under the sill plates (or just one of them) on either side of your catwalk. You're then basically hiding the expansion gap and allowing your floor to seamlessly disappear underneath it.

Honestly, it also depends on your bamboo. If you're nailing it down anyway, and this is NOT a very wide space, I don't think you have to be overly worried about excessive cupping and expansion. I used floating strand carbonized bamboo in my office, and that stuff can sit in water for days without bloating or warping. I cut my expansion joints in half, and have experienced no ill effects. It just doesn't behave as much like wood. Good luck!

Question I have: Do you have to worry about this kind of thing with stair edging? Wouldn't this effectively act the same way as a giant, continuous stair edge on both sides? I was under the impression that the expansion gap is required at edges that butt up to vertical surfaces, like walls.

Butted up against anything that isn't supposed to or won't move. Stair edging...do you mean the nose or the ends of a stair tread?

Jimmie, I am talking about the stair nose molding at the top of a flight of stairs. Some of these have a groove to accept the tongue of a piece of hardwood floor, so it is obvious that they are intended to be installed tight up against the flooring with no expansion gap. Aren't these usually nailed and glued down at the top of a flight of stairs? I do realize that another stair nose molding is made that overlaps the flooring to allow a gap.

I am not a professional, but I have been told by two different flooring installers that the expansion gap is not necessary in this application. Doesn't completely make sense to me, because it would seem that if there is a fixed object the floor would have to go somewhere if it expands.

The stair nosing is essentially a piece of flooring that has a rounded nose. If it wants to expand it will take the path of least resistance which is in the direction of its nosing so it won't be trying to move something that shouldn't be moved e.g. a wall, or pipe, etc.

So just so I am clear, you are saying that it should be OK to butt the flooring right up against the moldings that the OP was talking about, right? If not, please correct me.