The floor is the big decision and the trim is the afterthought, right up until the installer asks what you want done with the baseboard. Then it turns out there are three answers, they cost different amounts, and they look different for as long as you own the house. This is what each one involves so you can decide before the day rather than on it.
Why the edge is a question at all
Two reasons. First, a new floor is almost never the same thickness as the old one, so the gap between the floor and the bottom of the existing baseboard changes. Carpet and pad coming out and LVP going in leaves a visible gap under the base. Tile going in where vinyl was pushes the floor up into it.
Second, floating floors, which is most LVP and all laminate, need an expansion gap at every wall so the floor can move with the seasons without buckling. That gap is real, it is required by the manufacturer, and it has to be covered by something. We explained why in where one floor should stop and the next should start, and the same physics applies at the wall.
Option one: leave the base, add quarter round
The existing baseboard stays on the wall. The new floor is installed up to it, leaving the expansion gap, and a strip of quarter round or base shoe is nailed to the baseboard to cover the gap.
It is the cheapest option and the fastest, and it is what most installers will do by default if nobody says otherwise. It also looks like what it is. Quarter round is a small, rounded molding that visually thickens the bottom of the base and reads as builder-grade in a room that is otherwise well finished. On a tall, plain baseboard in a modern room it is particularly noticeable. On a traditional profile it disappears better.
When it makes sense: budget floors, rental units, rooms where the base is already thick and traditional, or where the base is tiled or otherwise not removable.
Option two: remove the base and reinstall it
The baseboard is carefully pried off, labeled by wall, the floor goes in with its expansion gap, and the same base goes back on, now sitting on the new floor and covering the gap on its own.
This gives the cleanest result with the trim you already have. The base sits at the right height, there is no added molding, and the room looks as if the floor was always there. The cost is labor: removing base without breaking it, filling the old nail holes, re-caulking the top edge and touching up the paint. Some base does not survive removal. Older painted wood base that has been caulked and painted a dozen times often splits, and MDF base that has ever been wet crumbles at the nails.
When it makes sense: good-quality existing base, especially a profile you want to keep, and a floor going in with a height change that quarter round would not hide well.
Option three: replace the base
The old base comes off and goes in the dumpster with the old floor. New baseboard, often taller and cleaner than the builder profile, is installed after the floor and painted. This is a finish carpentry job as much as a flooring job, and it is the option that changes how the room reads most.
It costs more than the other two, in material and in the carpentry and painting time. What it buys is a room where the floor and the trim were chosen together, which is the thing people notice without being able to say what it is. It is also the only sensible option when the existing base is damaged, short, or a profile nobody would choose.
When it makes sense: whole-floor projects, rooms being repainted anyway, houses where the builder base is the thin three-inch kind, and any project where the goal is a finished room rather than a new floor.
Door casing and the height problem
Baseboard is not the only trim a floor meets. Door casing runs down to the floor on both sides of every doorway, and a thicker new floor has to go somewhere when it gets there.
The right answer is to undercut the casing: a saw run flat along the top of a scrap of the new flooring, so the floor slides under the trim and the casing appears to sit on it. It takes a minute per door and it is how every professional installation handles it. The wrong answer is to cut the flooring around the casing profile, which leaves a visible outline that gets worse with every seasonal gap.
Doors themselves sometimes need trimming at the bottom when the floor comes up, and thresholds and transitions at every doorway are decided at the same time. Our transitions guide covers where those lines go.
Matching trim in older homes
La Crosse, Winona and the older village cores of West Salem and Sparta have a lot of pre-war housing, and the trim in those houses is often a tall, milled profile that no home center sells. When a floor goes in and a length of that base is damaged, or a room that never had it needs it, the choice is between a modern profile that does not match and a custom-milled or built-up profile that does.
We match profiles where it matters, using the original as the pattern. It is more work than pulling stock off a shelf and it is the only way the room ends up looking like it belongs to the house.
MDF or wood
New painted base comes in MDF or finger-jointed pine, and either paints well. MDF is straighter, cheaper and takes paint beautifully, and it is fine everywhere except rooms that get wet. In a bathroom, a mudroom or a basement with any moisture history, wood or a moisture-resistant product is the right call, because MDF that gets wet at the bottom edge swells and never recovers. Stain-grade base is solid wood, chosen to match the floor or the doors.
Painting, and the order
Whichever option you choose, the trim is installed after the floor and it needs paint or touch-up afterward. That puts a small painting step at the end of every flooring job, and it is the reason the sequence matters. Paint before or after new floors lays out the order for the whole room, and our interior painting service handles the trim visit as part of the same job.
Deciding before the day
The baseboard decision is made at the estimate, not on install morning, because it changes the price and it changes whether a carpenter and a painter are on the schedule. When we measure for LVP, laminate or hardwood, we look at the existing base and tell you which of the three options we would choose for that room and why. The steps around it are in what to expect from a flooring installation, and the free in-home estimate is where it gets decided.