We are having engineered flooring installed on our stairs. We have some disagreement with the installer and would like comments from others who have had this done. He says they need to leave an expansion gap and then use quarter round on the back and sides of the treads. The steps are enclosed on both sides with oak. The video on this site says not to use quarter round (or any trim), but we have had others tell use to use trim. If they use trim, how do you do the ends that show facing out on the tread (kind of tacky?)? We are really confused. Any help would be appreciated.

Im not sure about using strips or planks on steps. But when a customer is interested in getting there stairs done in hardwood. We install pre fabriced treds and raisers, we can have them pre finished or unfinished. When we install these there is no trim that is required and it looks amazing. Hope this helps =-)

Have you considered a different installer?
I did my own stairs with engineered. I used no quarter round, and there are no gaps. But, it takes time to get it to fit. The back of the stair is a no-brainer - it gets covered by the riser. And the front of the stair (the bullnose) goes over and covers the top of the riser. The sides will take multiple cuts to get the perfect fit - and to an installer that could mean wasted time and money. My opinion is the stairs look much better without the quarter round.

Stairs are cut tight. A tiny, tiny gap is better and caulk it. If you get the sides real tight, and the staircase has some bounce in the framing, the tight cuts will squeak. Been there, done that.

Run in the other direction of that guy! He has no business even getting involved. Trim on steps looks downright amateurish or "hacky"

Is that a word?