I'm not sure if you're on the right track but do some research on shellac before using it or hire a pro who knows how to do it right.

Here is a link that might be useful: shellac floor finish

My old wide pine floors have shellac on the margins (they had area rugs on them a loooong time ago). I am stripping it, sanding, staining, and applying polyurethane.

We had one room that we went 6 months between removing the carpet and refinish--the shellac was really difficult to live with. That may have been because it was 100 years old, but I suspect it was more the nature of shellac. Our woodwork is still shellac, and that is fine.

I've had great luck using Zinsser "sealcoat" shellac as a floor finish. Most importantly, it is a de-waxed shellac. Shellac that has not had the wax refined out of it is not suitable for floors, as it is much softer and very prone to water spotting as Brick mentioned. Dewaxed shellac dries very hard, coat after coat. Sealcoat is very pale and clear. If you wished to have a darker finish, I recommend a coat or two of dewaxed Garnet shellac to start, then finish up with the sealcoat (to save a ton of money as well, garnet flakes are about $22/lb.). Garnet gives a fantastic color to antique lumber.
I'd go with four coats of shellac for bedrooms, and probably six in higher-traffic areas.
Sealcoat is a 2 lb. cut, meaning there are two pounds of shellac flakes dissolved in a gallon of alcohol. Regular canned shellac like "clear" or "amber" is put up in cans as a 3 pound cut, and is hard to apply smoothly because it's so much thicker. The 3 lb shellac is slower to dry. And of course it has the wax problem.
I use a 4" wide staining brush for shellacking.
Casey

Casey, What do you think about using the Zinsser "sealcoat" for finishing window trim? We regularly open the double hungs that I'm thinking of...

Hi,
the Sealcoat is a very high quality shellac, as such it's perfectly suitable for woodwork, although I have two issues: 1) It's very pale and I happen to like a little color, so I always do two coats of the garnet shellac first (on my old-house woodwork) then use the clear sealcoat to build the gloss.
2) It's thin, so you have to use a good technique on vertical surfaces, like trim and doors to avoid runs, drips, and "curtains".
If you're applying it in a warm/hot day, you need to work incredibly fast to keep the necessary "wet edge" or you will be rubbing out the last coat.
Which brings me to my last point: If you rub out the last coat with 0000 steel wool and furniture wax, you will have a beautifully smooth finish that's very luxurious in feel and appearance.
Casey

'Super Blonde Shellac' is also dewaxed, but I would never suggest any shellac product for a floor that might get ANY water.

There are also darker shellacs available dewaxed.

I used the good old fashioned oil-based varnish on the woodwork in my living room, but I have no experience with it on floors. I chose varnish over shellac because I wanted zero shine and all shellac has at least some shine. I included a link to the Pratt & Lambert dull varnish I used in case you're interested. I started with one coat of de-waxed shellac to seal the wood, followed by 3 coats of the varnish.

I can't attest to how varnish holds up to foot traffic, but I found it easy to work with. I gave 24 hours of dry time between coats and sanded lightly between my coats. The end result is just what I was looking for. At some point I may wax it, but haven't yet.

Hope this helps.

Here is a link that might be useful: pratt & lambert dull varnish

Thanks, casey. I've already got amber shellac on the windows, but I need a better final coat. I'm going this route.

Does anyone know, if an amateur has made the mistake of using Zinsser Bulls Eye Shellac on her sanded-down hemlock floor, is there a way for her to salvage the project or does she have to strip the floor back down to bare?

Hi,

You have to explain the nature of your dissatisfaction. Is it the color, the shine, some problem in the application?

Casey

I am concerned about the floor blushing due to water exposure in a house of spills and lots of mopping.

My 1926 oak floors were shellac finished...when I took up the carpet, they looked wonderful. No sign of any water damage. I had some repairs made where there had been floor registers and ply wood used to fill in when the carpet was laid, so they had to be refinished.

Most finishes can be applied over dewaxed shellac, albeit the shellac may be a little soft and that may limit the longevity of the finish on top of the shellac.