How does one tell if a floor has been sanded to the point where it is not feasible to refinish again? For instance you get a call to go look at a job. What exactly do you do to tell or can you do it just by looking, pull a trim piece, measure?

Also what is the average amount of wood taken off on a sand an refinish job.

Thanks!

Ernesto,
Remove a floor vent and look there. As far as how much it depends on who's sanding the floor. Around 1/32.

Pig-pen is right! Easiest is to look where there is a register. Look at thickness of wood above the tongue. You can also ask the age of the house and/or how long the floors have been in. For a 3/4" T&G floor, one can easily get 4 to 5 sandings, including the first one UNLESS the floor was badly water damaged and cupped then sanded, then only a few sandings. The floors to watch out for are; 5/16" solid face-nail (handsetting all those nails is a killer), engineered/veneered (sanding through the top layer in spots looks real bad), very old floors where they used regular nails to nail the floor down by hand (you start running into the tops of the nails before reaching the tongue) or heavily waxed floors (talk about your edging nightmare; 36 grit loads up before you get two ft out of it), badly cupped floors (indicates moisture problems), and newer aluminum oxide finishes (they are a bugger to scrape the corners and use double the sandpaper, easily). 1/32" is average for a pro refinish although some start grinding with 30 grit no matter what condition the floor is in! WRONG! The idea is to remove the least amount of wood to effectively refinish the floors. Experience will teach you.

And if there aren't any vents? How often does one pull the base or trim off when refinishing? Probably couldn't tell if that was done?

How much do you think is left on this floor? From the Saw Grass mall in Sunrise FL two years ago.

Removing baseshoe would be considered normal for refinishing; sometimes even 2" reversable stain grade but never 8" painted colonial! Looks like this floor was patched and since it is in a commercial location and appears to be maple, I'd guess it's either in a store or on a stage of some sort. I would look for a place where the flooring terminated (exterior threshold, transition to another floor) and see if I could remove some trim to measure or observe the depth of the wood. Anything less than 9/16 from subfloor to top would be very questionable regarding resanding, especially when confronted with a floor in this bad of shape. I'd probably recommend replacement.

Ken, I sometimes take a thin putty knife and find a crack between the boards and push the knife down until it hits the tongue. This will tell you how much wood is there. I would do it in a high traffic area if you can.
Buddy

GREAT TIP!

Very interesting, thanks guys!

I thought at least a 1/16 to 3/32 to remove dents and such.