Tech Talk: Effective Approaches to Resanding an Old Floor

“Specific to old wax or shellac, what is the most effective approach you have to resanding an old floor?”

John Alford – Alford’s Custom Hardwood Floors

There are several factors to consider when resanding a shellac and wax floor and not going back with the same finish process. First, the abrasive you go through easily will double, if not triple, on the first cut as the shellac with heat up and re-emulsify, filling up your paper. You may need to drop down to as low of paper as 16 grit to effectively remove the wax and shellac. After that, you can sand as normal.

Be careful of which finish you are going with back on the floors as the wax and shellac can be deep into the grain and down in between boards. We usually seal coat with dewaxed shellac before applying any urethane finish so that any remaining wax is blocked.

Adrian Molitor – Molitor Traditional Flooring

When I go on an estimate for any home on the historic registry or that’s more than a century old, in general, I typically do a spot check for any obvious structural issues like a floor joist that’s lifting or any potential areas that are on stilts from the foundation up. This is mainly because I may not be able to restore the floors at all if the top of the groove is getting too thin. It’s important to be able to offer a solution if that’s the case.

When I do work on a floor that may be covered in a mystery solvent/wax I never start with the edger, I use our belt sander at the lightest tension. I also access my normal grit sequence and go a grit less aggressive (if 36, start with 50). We try to edge as high as possible considering how aggressive the edger is. The main thing is to explain to clients that history is never perfect, but always worth restoring. We prefer this work over anything else!

Daniel Moore – Antique Floors

I see a lot of houses from the 18th century and there wasn’t traditional floor sanding or finishing equipment until after Reconstruction. The Department of Historic Resources wants to see certain elements of the house preserved. They want to see the replacement go back the same with the floor joists and flooring assemblies as well as the finish type and the way that it looks. They want to make sure you maintain that same installation application even though a lot of times it was not the most effective way to go about it.

For waxed floors done prior to the late 19th century, you don’t put polyurethane on it and you don’t put waterbased finish on it. Generally, you want to stick with wax, wiping it on and buffing it off using a small orbital buffer removing the excess. A lot of times, they might not let you sand and finish so all you’re able to do is spot repairs to freshen the floor up a little bit.

If you’re doing a buff and recoat in a historic setting, you’re treating it more like when you’re waxing a car. Steel wool or Sandpaper grit at 320 and 380, 400, 600 begins to do a unique thing if you have your DCS hooked up with your orbital sander as you’re running around the edges. It has a way of lightening it up and giving your intercoat abrasion process a chance to actually work in concert with using your favorite thinner.

Overall, each house is going to have a unique history and you’re playing by the guidelines from the Department of Historic Resources.

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