The real difference is the bevel, and whether you can ever match this floor
Both arguments people lead with are true and temporary. Prefinished is walkable sooner; site finishing makes dust that extraction reduces and never eliminates. Those are days. What is permanent is that a prefinished floor has a bevelled seam at every board, and that only a site finished floor can be matched into an existing one, which in a region where 60.5 percent of the housing predates 1978 comes up constantly.
The short version
- Prefinished boards carry a micro bevel at every edge, because a factory finish cannot be sanded flat after installation.
- A site finished floor is sanded as one surface, so the plane is continuous and the seams disappear.
- Only site finishing can match new wood into an existing floor, because old and new get sanded and coated together.
- Dust and schedule are real differences measured in days; the bevel and matching are permanent.
- In this region matching comes up constantly: 60.5 percent of housing in our dataset at /data/ predates 1978.
Why prefinished floors have a seam at every board
Because boards are never perfectly level with each other and a factory finish cannot be sanded flat after installation, so each board carries a small bevel that makes the height change look intentional.
The bevel is a solution, not a defect. Without it, tiny height differences between adjacent boards would read as a fault. With it, they read as a design line.
The consequence is a floor made of individual boards rather than one continuous plane, and a small channel at every seam where dirt collects. Some people prefer the look and choose it deliberately. Others do not notice until the afternoon light comes across the floor at a low angle.
Look at a sample with light raking across it rather than flat on. The bevel only shows at a low angle, which is exactly how you will see it in your own room.
Ask to see the sample on the floor, with the light from a window across it. Held in the hand at eye level, a bevel is invisible.
The case that settles it for most houses here
If anything has to match an existing floor, site finishing is the only path, because matching means sanding old and new together and coating them as one surface.
Extending a floor into a new room, opening up a wall, or repairing a section all produce the same requirement: a joint that disappears. A factory finished board will read as a different floor beside an older one no matter how close the colour is, because the two were finished at different times under different conditions and are ageing on different curves.
Site finishing puts old and new under the same sander and the same coat. That is the whole mechanism, and there is no substitute for it.
In this housing stock the question comes up constantly. Our dataset at /data/ has 60.5 percent of the region built before 1978, which means most projects here are meeting an existing floor somewhere.
| Situation | Answer | Reason |
|---|---|---|
| Anything has to match existing wood | Site finished | Old and new sanded and coated as one |
| Whole floor new, nothing to match | Either | Now it is a preference about the bevel |
| House cannot be empty for long | Prefinished | Walkable when the last board goes down |
| You want one continuous plane | Site finished | No bevel, sanded flat as one surface |
Dust and schedule, honestly
Prefinished is walkable immediately and site finishing needs sanding, coating and cure time, and no sanding job is dust free regardless of what it is called.
A prefinished floor is done when the last board goes down. A site finished floor needs a schedule, and the schedule has two dates on it: the day you can walk on it, and the day it has finished curing. The second one is the one that protects the floor.
On dust, extraction catches most of it and not all of it. Anyone promising a dustless job is selling a word rather than describing a process, and we say the same thing on our sanding pages.
Both of these are inconveniences measured in days. The bevel and the ability to match are permanent properties of the floor you will live with for twenty years. Weighing a week against twenty years is how people end up regretting the choice.
Questions
Which lasts longer?
Factory finishes are cured under conditions a house cannot reproduce and are usually harder. A site finished floor can be recoated without replacing anything, which over decades matters more than the initial hardness.
Can a prefinished floor be refinished later?
Solid prefinished, usually yes, and the bevel disappears when it is sanded flat. Engineered prefinished depends entirely on the wear layer thickness.
We are adding a room onto an existing floor. Which one?
Site finished, with old and new sanded and coated together. A factory board will read as a different floor no matter how close the colour is.
Is site finishing very dusty?
There is dust. Vacuum extraction catches most of it and never all of it, and anyone promising zero is selling a word.
How long until we can use the room?
Prefinished, the same day the last board goes down. Site finished depends on the coating, and we give you both the walkable date and the cured date rather than an average.
Sources and references
- Deco Hardwood Floor, housing stock of the Philadelphia region (CC BY 4.0). https://decohardwoodfloor.com/data/
- National Wood Flooring Association, finishing guidelines. https://nwfa.org/
Keep reading
Pillar GuideRefinishing a floor in an old Philadelphia houseWhat decides whether your floor can be sanded, and why the answer here is different from the answer in a newer suburb.
Decision GuideSolid or engineered, and why the basement decidesThe choice is presented as taste. It is usually settled by what is under the room, before anyone gets to taste.
Code ExplainerThe lead rule decides how your sander is builtIn a region that is 60.5 percent pre-1978, this is not an edge case. It is the default condition of the work.
Send a photo and we will tell you what you are looking at
Floor Installation starts with someone reading the house. We quote every job ourselves, with no salesperson in between, and a photo of the floor gets you a straight answer faster than a form does.
