How to Sand a Hardwood Deck: Full Refinishing Guide

Introduction

Sanding a hardwood deck is the best way to restore the natural color and smoothness of weathered Ipe, Cumaru, or other tropical hardwood boards. While these dense woods require more aggressive equipment than softwood decking, the results are dramatic — turning a gray, weathered surface back to its original warm, rich color.

This guide covers the complete process: preparation, tool selection, grit sequence, and finishing.

Key Takeaway: Sanding Ipe and tropical hardwoods requires a drum or belt sander — random orbital sanders alone won't cut through these dense surfaces efficiently. Always sand with the grain.

When to Sand vs. When to Clean and Re-Oil

Sanding is the right approach when:

• The deck has grayed significantly and re-oiling alone won't restore color
• There's uneven weathering or discoloration across the surface
• Previous finishes have built up unevenly
• There's significant surface checking that you want to reduce
• You're restoring a deck that has been neglected for several years

If the deck is only lightly grayed and in otherwise good condition, cleaning and re-oiling may be sufficient. See our maintenance guide for less intensive restoration options.

Tools and Materials

Essential Equipment

• Drum sander or belt sander (rental available) — required for stripping and initial cut
• Edge sander — for areas the drum sander can't reach
• Random orbital sander — for finish passes and detail work
• Shop vacuum or dust collection system
• Sanding belts/drums: 40-, 60-, and 80-grit (start coarser than you think you need)
• Ear and eye protection, dust mask

Materials

• TSP (trisodium phosphate) or deck cleaner for pre-sand prep
• Deck brightener (oxalic acid based) — optional but recommended after sanding
• Hardwood deck oil (applied as finishing step)

Step-by-Step Sanding Process

Step 1: Prepare the Deck

• Remove all furniture and planters
• Sweep thoroughly
• Check for protruding fasteners and countersink any that are above the surface (they will destroy sanding belts)
• Inspect for any boards that need replacement before sanding

Step 2: Start with 40-Grit (Rough Cut)

Begin with 40-grit on the drum or belt sander for decks that are heavily weathered. Sand with the grain — never across it.

Ipe-specific note: Ipe's extreme density means 40-grit will cut slower than you expect on softwood. Use sharp belts and expect to change them more frequently.

Move the sander continuously — stopping in one place will create a depression.

Step 3: Progress to 60-Grit

Switch to 60-grit to remove the scratches left by 40-grit and level the surface. Again, sand with the grain across the full deck.

Step 4: Finish with 80-Grit

The 80-grit pass creates the final smooth surface ready for finishing. This pass should be done with both the drum/belt sander and the random orbital for a consistent result.

Step 5: Edge Sand

Use an edge sander at matching grit sequence along the perimeter and between any areas the drum couldn't reach.

Step 6: Detail Sand

Use a random orbital sander by hand around posts, railing bases, and corners.

Step 7: Vacuum and Wipe Down

Vacuum all sawdust thoroughly. Wipe down with a tack cloth or dry cloth to remove fine particles.

Step 8: Apply Deck Brightener (Optional but Recommended)

After sanding, the wood's pH may be slightly elevated. A deck brightener (oxalic acid) neutralizes the surface and opens the grain for better oil penetration. Follow product instructions.

Step 9: Apply Hardwood Deck Oil

Apply deck oil within 24–48 hours of sanding while the wood grain is fully open. See our maintenance guide for oil application instructions.

Common Sanding Mistakes

• Cross-grain sanding: Leaves scratches visible after finishing. Always sand with the grain.
• Stopping the sander while it's running: Creates dips and depressions in the surface.
• Skipping grits: Going from 40 to 80 leaves deep scratches that 80-grit can't fully remove.
• Not countersinking fasteners: A protruding screw can tear a $25 sanding belt in seconds.

FAQ

How often should I sand my Ipe deck?

Sanding removes material from the board surface, so it shouldn't be done every year. A well-maintained Ipe deck may only need sanding every 5–10+ years. Annual cleaning and oiling reduces the frequency of needed sanding.

Can I rent a drum sander for an Ipe deck?

Yes — drum sanders are widely available at tool rental stores. Specify that you're sanding a very dense tropical hardwood so you get appropriate equipment.

What grit should I finish with for Ipe?

80-grit produces the standard smooth surface for Ipe. Going finer (100-120 grit) creates an extremely smooth finish but may reduce oil penetration. Finish at 80-grit for the best combination of smoothness and oil absorption.