Small quarter-round or small square molding. Of course, it needs to be mitered at every turn, and there are lots of turns. The only other fill would be white caulking applied very very carefully and cleanly.

The contractor has suggested caulking. My concern is that it will get grubby looking, or come out over time, the way I've seen other caulked joints come apart.

So I'm leaning towards small quarter-round molding, unless I get a lot of recommendations for caulking.

I imagine installing molding would be more expensive. But I've often regretted taking the cheaper solution for some other things in our house. So I'm willing to consider spending more now, if it's going to wear better over the next 10-20 years.

I would definitely install quarter round to give it a clean look. On a side note, I'm curious why the contractor didn’t remove the old flooring? Wouldn't two layers of wood floor put a lot of strain on the house? Also, why cut the bottom of the baseboards to slip the new floor under it? Wood expands & contracts throughout the year, so you don't want it to buckle. Just a thought.

I'd choose trim instead of caulk.

And try to have it butt into the door casing as shown here.

the real issue here is why it's jagged. To me, it's poor quality. you shouldn't have to hide poor quality. the jagged ones should be replaced. Using quarter round is meant for aftermarket flooring where you don't want to replace the baseboards. these are new baseboards. you shouldn't have to use quarter round unless the floor is so uneven, you have tons of gaps.

the least he could have done was take a fine sand to smooth the edges. lazy workmanship.

The flooring should have butted up to the baseboard. The wood will expand and contract during the summer and winter months. Shoe or quarter round molding painted the same color of the baseboard will hide the gap.

i don't think the gaps are the issue. he's talking about the jagged edges. why couldn't the worker have sanded those edges? he obviously cut them to fit the rise of the flooring, but didn't do a bang up job at it.

Thanks all for these comments. The baseboards are from the complete renovation we did 10 years ago. The old floor was the original doug fir subfloor; we opted to not re-do it when we redid everything else, which is a decision that I later regretted. Live and learn.

I was pretty surprised at the jagged edges for this recent job, but what's done is done. I did ask about sanding those lower edges, they are telling me it's not an option. This may or may not be true, but seems to me that sanding would be pretty time intensive and would still leave us with a gap of varying size.

So seems best to just move on to covering up the gap with trim...guess I will now need to figure out whether we should have quarter-round or something else.

The jaggedness is pure laziness on the worker. He should have used a jamb saw and adjusted the height on the blade for a straighter cut.

Go with shoe molding. 3/4" x 1/2"... the 3/4" side will run along the baseboard. Much cleaner than normal 3/4" x 3/4" quarter round.

Is this a 2 piece molding? Have them simply pry off that piece and scribe and plane it to fit properly. Why go through the trouble of putting show molding when the real issue can be addressed by fixing that molding.

Wood floors expand and contract in width and length. To be technical yes i guess there would be height but it does not need to be accounted for. My baseboard moldings are scribed, planed and sanded if needed to fit the height differences of the floor. Here we have the case of someone who installs molding and is NOT a carpenter.

Fix the problem don't cover it and create even more expense and work. It a 20 minute fix at most.

wannabath, the baseboards are jagged like this throughout the whole flat, because the new floor was installed in the whole flat. It seems to me that prying off all the baseboards and fixing them would be a much bigger deal than laying shoe molding along all the baseboards.

Wannabath, aesthetically it would look better to pull the baseboard, replane and replace. Cost efficiently, adding a shoe molding is easier on the wallet.
There's always that chance to damage the wallboard behind the baseboard when removing. That is another item I wouldn't want to pay for.

If your flooring was pre stained, the manufacturer may have shoe moldings available to match. Wood doesn't show as much wear and tear. Have a look at pictures on Houzz to see if you like it. You can also buy oak trim and stain and seal it yourself with the same floor stain/sealer.

wannabath,,,perfectly said. I concur.

for me, i'd rather have small potential issues with caulk here and there than shoe molding everywhere.

tape the floor before you get out the caulk gun to save a smeary mess.

Totally with Beth H and wannabath!

The baseboards should have come up when new flooring was installed.

At this point the baseboards should be replaced because it distracts from the new floor and like mentioned, quarter round looks cheap and is an obvious cover up.

Agree -- when I got new floors, they removed all the baseboards first and then reattached so everything was a smooth fit. Cutting them instead is lazy and honestly hard to imagine, let alone cutting them like this. I'd want them all fixed (at the remove the lower portion and rebuild the wood as needed, then reattach, level), as even shoe molding will extend beyind the doors. But perhaps you had a budget contract that didn't involve handling the baseboards, in which case it's caulk or shim-and-fill...

Thanks all. Well, what's done is done. The person who did the work really want to caulk. I think we will start with trying that and if it doesn't work out, we'll look into adding molding...or possibly redoing the baseboards, but that sounds more time consuming and disruptive, which means we'd have to put it off for a while.

It's strange to my why everyone wants to do a half butt job on finish work. The right way to do this is to scribe it. In your case you may need to start out with a taller piece and then scribe it so that the finished product doesn't look shorter once it's cut.

Can you share the finished work?

I would not allow someone to put caulk on my brand new wood floor. What color cault is this supposed expert proposing? I find this appalling. If someone did that to baseboards that I had previously paid for and installed, I would NEVER allow them back in my house. I would start saving for new basebaoards. In my view, they appear ruined.