How to Sand Wooden Floor Corners Properly — Without Losing Your Nerve (or Your Edges)

Corners.

They’re the one part of a wooden floor where even the best contractors sometimes wince. You can sand a floor smooth ready for an oil or a lacquer— but if the corners are patchy, scratched, or poorly prepped, the whole job looks unfinished. Here’s a straight-up guide to doing corners properly — and the kit that’ll save you hours of faffing.

Step 1: Remove Existing Finish

Before you even touch abrasives, start with a proper corner scraper. Corners often carry built-up finish, grime, or old lacquer that clogs papers fast. Scrape first, sand second. You’ll find similar to the edges that the corners are not walked over. So there will ne no wear on the original finish that was down. They are also breeding grounds for dust, debris, and dirt. Save your abrasives from getting clogged with pooled-up polishes, cleaning products, and tough finishes. Your first point of call should be the trusty scraper... Every wood floor sander should have one attached to their hip!

Best corner scrapers we recommend:

Bahco Carbide Pocket Scraper (BAH625) –  small, compact, and precise. This small option for a scraper gives you the flexibility and movement for tight spaces. Not only comes but behind the pipe work, radiator pipes. And stair risers and spindles. Tough 3-sided blades allow you to turn the blade allowing for 3 cutting edges. Saving you having to change the blade so regularly.

Ultimate Carbide Triangle Scraper – wide grip, Long handle that allows you to apply more pressure when pulling to remove the top coat using leverage. The Replaceable triangle Scraper blades are made to reversible, giving a new cutting edge 3 times without having to replace blades so often

Ultimate Straight  Scraper with Flat Handle – The traditional Straight Scraper. Designed with a 50mm interchangeable tungsten carbide blade. The blade slightly overhangs either side of the blade holder, allowing for the corners of the blades to get right into the corner of the floor.

Tip: Always scrape with the grain and clean your blade often. You'll feel it cut better — and save your arms in the long run. If you need to scrape at a 45-degree angle to the grain, but have your final scrape follow the grain.

🪵 Step 2: Choose the Right Corner Sander (or Attachment)

There are two main ways to sand corners properly once the surface is scraped. These two machines have been industry tested and come with the right backup and attachments needed for floor restoration:

✅ Option 1: Festool Deltex + Deltex Starcke Sheets

If you’ve got a Festool Deltex, it’s one of the best tools for detailed corner work. It gets in tight, and you’ve got full dust extraction. There are 2 different types on the market. The older version has a more stable head on. Simply replace the Velcro. The newer versions give you options to interchange the head for an ro90 90mm disc. The benefit of this machine is hooked up to the Festool extractor, can provide optimum dust extraction. The Starcke Deltex aluminium sanding sheets we provide some with the correct hole alignment to help with scratches and provide more dust removal.  Fine them ranging from 40grit to 80 grit here – Starcke Deltex sanding sheets Match it with Starcke Deltex-Fit Sanding Sheets — they’ve got the exact hole pattern for airflow and extraction. Less clogging. Better cut. Proper fit at 88mm x 95mm

✅ Option 2: Fein Multi Tool + Starcke Triangles

Running a Fein Multimaster with the corner sanding head? Use Starcke 83mm Aluminium Oxide Corner Triangles (Fein fitting) — they hold up under pressure, come in the grits you need, and actually reach the edge. The benefit of using this machine for sanding the corners is the tool is as it says multi. The half moon and straight cutters that csan attach to these tools can really come in handy when your doing repair or pine board replacements. Also if you are a contractor that like sto offer pine slithers to your clients cutting the top off with a multimaster saves many passes with the belt. Quick effective and multi purpose. Only thing with this system is it doesn’t have the hole configuration for dust extraction.

Step 3: Work Through the Grits

Corners don’t get a free pass on quality. Treat them like the rest of the floor:

Not every corner needs you to start with a scraper. But it is best practice. Sometimes you only need to sand with your choice of corner tool, you’ll see from our stocks that we only supply the corner sheets in 40 , 60 , 80. That is because with the corners, we follow the following process. Start low, 40 to remove the top, remove the 40 scratches with a 60, and finish with an 80, vacuuming between these grits and in some cases brushing away.

Sounds a bit contradictory saying the corners are so important to dish out properly, and then in the same article say finish the corner on an 80 even if you're going to 120. I've tried this myself there's no shadowing in such small areas of the corners where the Rotex can't reach. Try it yourself with our Starcke range

I walked into many pubs and looked at the corners and thought the peaks show that a sander hasn’t been anywhere near that corner. Even in domestic homes I’ve seen it. It’s a must. I get it sometimes you’re on a commercial job and you have 200 square meters to sand and seal in closing hours. But you can’t put a price on the quality of your work and what you are willing to put your name to. use abrasives that are made for your machine and your corners — not just whatever’s left in the van.