Should I stay or should I go? (A bit vague, but a nice Clash reference.)

If you don’t sand floors every day, it’s hard to tell by looking if your particular floor is even worth sanding.

But you are smart to ask that question BEFORE you start sanding.

Almost every hardwood floor has a history. Most people don’t get the luxury of choosing their floors; they inherit one with a past. By the time people get to Pete’s, they know they want to keep their floors, but make them look perfect again. But this can depend on what caused them to degrade in the first place.

Wear from dirt, dog toenails, and long periods of foot traffic sands out 98% of the time.

But damage from liquids, particularly urine, is often permanent. But it is difficult to know just by looking at a stain or mark whether your floor is worth the effort of refinishing.

If you are in a panic about whether your floor can be saved or not, here are some images that may help you understand what is going on. And give you some hope.

Look at these two photos.

This photo looks like nothing – those little lines should just sand right out, right?

Alas no; when people use utility knives directly on the wood floor, usually to cut up carpet, the marks are just too deep to sand out.

But look at this photo. That floor looks like it’s on death’s door. This customer had planned to take chemical strippers and scrapers to it, but we convinced him to try a sander first.

Look at that dreamy white oak, quietly hiding underneath all that adhesive.

Here are some commonly encountered wood floor problems:

Years and years of wear-and-tear—this is what sanders were designed to fix. 

Old finishes get damaged foot traffic and furniture dragging. Or the finish gets too thin, exposing the wood beneath, which can get dirty and water-damaged.

This is surface damage that will be vastly improved, if not completely erased by sanding.

Can it be saved? Yes.

Machine marks inherited from previous sandings.

This floor was sanded by someone who overestimated their drum-sanding ability – can you see all the stop marks? This floor will need some aggressive sanding, but you can get these marks out.

Can this floor be saved? Yes.

Pro tip: if you do a coarse pass on an old floor and discover marks like these, the most efficient way to remove them is crosscutting with the drum sander using 36-grit. Don’t keep sanding this with 16-grit or 24-grit – those are really designed for taking off thick layers of finish above the wood.

As you are about to see in the next photo.

Old thick shellac finish “alligatored” from heat and sunlight. 

It will be annoying, but sanding will remove this. The old shellac will melt under the friction caused by the sander, but that is why they make those wonderful coarse grits.

Using 16-grit on the drum sander and possibly even 12-grit on the edger is a great solution for this.

Can this floor be saved? Yes.

Extreme Pet Damage.

This will not sand out. This will not bleach out. Vinegar will not help. When pets urinate on carpet, the carpet keeps the liquid from evaporating, so it decomposes into ammonia. The deep, burning damage is so deep that you have to remove the wood and replace it.

In instances as bad as this, it is likely the odor of the urine has even soaked into the subfloor below.

Can this floor be saved? Nope.

Paint, mildew, and areas of different coating types.

No worries. Sanders will chew through this. But have the coarsest grits on hand for the early stages, you’re going to need them.

Can this floor be saved? Yes.

Time does crazy things to unprotected wood

This looks so easy to fix, you say. Just sand the strip down the middle a little harder, right? But this photo was taken after all that sanding was done – this is as good as it got. We think this hall was covered with a carpet runner before the wood was coated with any finish, probably somewhere around 1920.

The exposed wood edges that were protected with a varnish did not darken with time and oxidation. But the area under the rug that never had a film coating applied, continued to change, and the color change is so deep in the wood that it is effectively permanent.

Can this floor be saved? No.

Here are more common floor issues.