I’m installing engineered wood flooring (floating) on the second story and I’ve come to the part where I have to install the floor around the stair opening. Screwing the iron balusters  through the flooring into the sub floor seems like a bad idea, for obvious reasons. I’m considering a few different options:

1. Drilling enlarged holes where the balusters to the floor, theoretically allowing the floor to still move. Unsure how well this would work; it’s possible the friction of the floor sandwiched between the sub floor and the balusters will effectively keep the floor from moving.

2. Screw the balusters to the floating floor only, not penetrating into the sub floor. This will allow the floor to move, but it will will also allow the balusters and railings to move. Is that bad? The flooring is 1/2″ baltic birch plywood core.

3. Stop the floating floor short of where the balusters run; install a strip of flooring under the balusters, fixed to the floor, install t-molding to cover the gap. This is the most certain to function properly, but the most work and the least aesthetically appealing.

3b. Same as above, but instead of using flooring under the balusters use custom milled solid wood, which would have an integral lip that covers the gap to the floating floor, and also an apron to cover the top edge of the drywall in the stairwell. This would look better than option 3, but is yet more work and expense. I guess I could also install a simpler piece of wood, and then undercut it with an oscillating saw to allow the floor to slide under it. I’m not sure that’s less work.

Opinions?