How to Sand Drywall

Getting a great paint or wallpaper finish requires perfectly smooth drywall. Unevenness in the drywall will be carried through to the finished wall, and may even prevent you from installing tile. Learn how to sand drywall and how to control dust and the right techniques for getting a perfectly smooth drywall surface through sanding.

How to Sand Drywall

Sanding is the first step toward achieving a flawless finished drywall surface.

1. Fill grooves and gouges first. Grooves and gouges in drywall are inevitable, and they should be fixed — but not by sanding. Attempting to sand out a gouge can damage the paper face of the drywall, and will result in an uneven surface.

Instead, fill gouges and groves with joint compound and a putty knife. It may take several coats, delaying your process as you wait for the joint compound to set, but the results are worth it.

2. Manage dust. Sanding drywall generates a lot of very fine dust that hovers in the air and settles on every surface. To make matters worse, it’s difficult to remove. Check the section below for tips on managing dust while sanding drywall.
3. Choose a sanding tool. See my list below for help deciding what tool best suits your situation.
4. Pick your grit. Drywall is a very soft material, so it can be effectively smoothed without resorting to aggressively gritted sanding paper. In fact, sanding paper that is too coarse can damage the surface of your drywall.

120 or 150-grit sanding paper and sanding sponges are perfect for sanding drywall. These fine-grained sanding tools remove excess material without leaving sanding marks behind.

5. Attach the paper to the tool. (Hand and pole sanders only.) The sanding surface of a hand or pole sander is essentially a flat board, with clamps on either end to hold sanding paper taut across the board’s surface. Slide the ends of the sandpaper under the clamps. Tighten the clamps, ensuring that the sandpaper is taut and flat against the sanding surface.
6. Sand strategically. You don’t need to sand the entire surface of your drywall, and in fact, you shouldn’t. Use light pressure to avoid disturbing the drywall’s paper face. Sand along each seam. Sand over the screws.
7. Check your work. Unless you’re a drywall pro, chances are you missed a few spots in your first pass. Unevenness in the drywall can’t be fixed after the finish is applied, so it’s now or never.

Hold a bright light close to the wall, shining across it horizontally. This will reveal any imperfections remaining in the drywall. Circle these trouble spots with a pencil and revisit them until your surface is perfectly smooth.

8. Sand again after priming. After your primer has dried, carefully check the surface of the drywall using a bright horizontal light for paper fuzz and other bumps. Sand out these imperfections and re-apply primer to prepare the surface for paint, wallpaper, or tile.

Learn the differences in drywall and sheetrock.

Drywall Sanding Technique

Use the following tips to make sanding drywall easier and more effective.

• Angle the sander slightly rather than pressing it flat against the wall. Minimizing the amount of contact between the sanding paper and the drywall ensures you won’t remove too much material.
• Use light to medium pressure. Don’t lean on or push the sander.
• Change sandpaper frequently. Plan to use one sheet of sandpaper for an average-sized residential wall. When you notice that sanding has become more difficult or slower, that’s a good sign your sanding paper needs to be changed.
• Don’t scrub. Moving back and forth repeatedly on the same spot can lead to oversanding, which will require repair. Instead, sand in multiple, random directions, approaching the area to be sanded from different angles.
• Avoid electrical boxes or other openings when using hand and pole sanders. Use a sanding sponge to get smooth edges around openings in your drywall or near electrical boxes.
• Don’t oversand. Oversanding happens when you press too hard or remove too much material. The tape used to connect two sheets of drywall must be completely covered before finish can be applied. If you over sand, the only solution is to recover the seam and resand before priming.

Drywall Sanding Tools

Different sanding tools are used to sand the various areas of drywall.

• Sand accessible seams with a hand sander for maximum control.
• Sand hard-to-reach areas with a pole sander.
• To sand corners, use a sanding sponge.

Hand Sander

A hand sander consists of a flat sanding surface with a handle on the back. Sanding paper is attached to the sanding surface.

Hand sanders distribute the pressure evenly over the surface you are sanding, leaving it even and smooth. They are easier to control than pole sanders.

Hand sanders are not usually meant for sanding corners. For that, you need a sanding sponge.

Pole Sanders

Pole sanders allow you to sand drywall from a distance, making it easier to cover large areas without constantly moving your ladder.

The sanding surface and pole are connected by a ball-and-socket joint with enough flexibility that it’s easy to flip the sanding surface over accidentally. Flipping the sanding surface over is a problem because contact with the edge or corner of the sanding surface can gouge the drywall, necessitating repair.

The closer you are to the sanding surface, the easier it is to control. If you want to try a pole sander, start out holding the pole six inches to a foot above the sanding surface. When you can control the movement of the sanding surface you can start moving further back.

Open-Mesh Sanding Screens

A sanding screen is a tool used by drywall professionals to make clean-up easier. It allows dust from the drywall to fall directly through the mesh into a collection area. However, they also make it very easy to damage your drywall.

If you’re planning to do a lot of drywall sanding, it could be worth it to master the technique, but you have to be prepared to repair your mistakes.

Sanding Sponge

A fine-grit sanding sponge has the size, shape, and maneuverability to sand inside corners without gouging the opposite wall. Use it instead of a hand or pole sander for tight corners.

Controlling Dust While Sanding Drywall

Make sure you have a plan to control dust before you start sanding drywall.

• Trapping dust as it comes off the drywall is the most effective solution. Some hand sanders can be connected directly to your shop vac hose, eliminating much (but not all) of the dust generated by sanding drywall.
• Remove personal belongings from the area and put drop cloths over anything that can’t be moved.
• Seal up your workspace with plastic sheeting to prevent dust from migrating to other rooms.
• Dust from drywall can irritate your throat and lungs, so always use a tight-fitting dust mask when sanding drywall. The dust mask will get clogged with use, so plan on changing that mask out after every thirty minutes of sanding.
• To avoid introducing drywall dust into your washing machine, wear disposable coveralls when sanding drywall.
• Drywall dust can irritate your eyes. Safety goggles seal out drywall dust and help keep your vision clear. Safety glasses are another option, although they may allow dust in around the edges.
• Consider having a dust collector to vacuum up remaining dust once you’re done.

Conclusion

Sand the seams of drywall using 150 grit sandpaper on a hand or pole sander. A 150 grit sanding sponge cleans up corners without gouging walls. Keep the sander at a slight angle to the drywall.

Use light pressure and multi-directional strokes to smooth out the drywall mud without fuzzing the paper. Check for mistakes before and after priming to ensure a perfectly smooth surface.