Wet Sanding Drywall Mud to Make a Dust Free Room

  • 01 of 06

    Drywall Wet Sanding: Materials Needed

    Attic with new drywall
    Banks Photos/Getty Images

    Drywall dust is the byproduct of sanding drywall with a screen or sandpaper. Dust is difficult to contain; it flies everywhere; it travels to the farthest regions of your home and is difficult to remove.

    Drywall dust is so incredibly fine and invasive that the warranties of some house vacuums are considered void if you use them to remove drywall dust!

    One method of reducing your dust output to nearly zero is called wet drywall sanding.

    Smudging, Not Sanding

    Wet sanding does work, but it is hardly a panacea for all drywall woes. It is more a process of "joint smudging" than sanding since so much of the drywall compound remains on the board rather than on your sponge.

    But there is real value to smudging out the edges of the joints because it makes the seams less visible or even invisible after painting.

    Clean But Imperfect

    • It Is Slow: Wet sponging drywall compound is a slow, difficult process―slower than dry sanding. If you're interested in speed, you'll want to dry sand.
    • Does Not Produce a Perfectly Smooth Surface: Because you are using a sponge―which is flexible―your end product will exhibit gentle waves.

    What You Need

    • Drywall Sponge: Either one you buy from a hardware store designated for this purpose or a very thick and sturdy household sponge.
    • Bucket: A large, clean bucket. It is best if the bucket has not contained caustic chemicals before this.
    • Water: You will need a nearby source of clean, warm water.
    • Dump Point: Because you will frequently be changing out the compound-laden water, you need a place to dump it. Do not dump down your drain as the compound may solidify and cause your pipes to clog. Drain augering will be the only way to remedy this.

    The Process In Brief

    1. Soak a sponge in a bucket of warm water, then squeeze out.
    2. Start with light, circular motions. Let the water do the work more than pressure from your hand. Right now, you are just concentrating on the high ridges and the spiky portions.
    3. When it gets too difficult, or the smears are too thick, rinse out and squeeze sponge in a bucket. The sponge should be wetter than on the first pass.
    4. On this second pass, since you have already taken down the high ridges, you can concentrate on lowering the joint compound "bump."
    5. After two passes, you are done. Any more wet sponging will get the drywall paper too wet. If two passes are not sufficient, you may need to dry sand the joint compound.
    Continue to 2 of 6 below.
  • 02 of 06

    Fill Water and Wring out Sponge

    Wringing a sponge next to drywall
    Lee Wallender

    Fill the bucket with lukewarm water.

    Dip and then wring sponge. Conventional wisdom says to wring out the sponge as much as possible. But because drywall sponges are so good at expelling water, hard wiring will leave the sponge almost bone-dry.

    You do not want a sopping sponge. But easing back on the wringing will leave enough water in the sponge to loosen the joint compound.

    Continue to 3 of 6 below.
  • 03 of 06

    Sand Joint With Abrasive Side First

    Sanding the abrasive side of drywall
    Lee Wallender

    Begin by knocking down any obvious high spots with the abrasive side of your sponge.

    This is where dry-sanding is valuable, because sanding with a screen or sandpaper reduces those high spots instantly, with minimal effect to surrounding areas.

    Move the sponge in broad, circular strokes.

    Pressing too hard in any one spot will create depressions in the joint compound.

    Continue to 4 of 6 below.
  • 04 of 06

    Sand on Smooth Side

    Sanding the non-abrasive side of wet drywall
    Lee Wallender

    Wring out the sponge. Switch sanding to the smooth side. This is where you begin to feather the joint compound outward from the joints. This reduces the visibility of seams after painting.

    Continue to 5 of 6 below.
  • 05 of 06

    Before and After Sanding Drywall With a Sponge

    End results of sanded wet drywall
    Lee Wallender

    The main value of wet drywall sanding is to smooth out and feather those ridge edges.

    Compare the "before" joint with the "after" joint. The "before" joint has a defined line. Running your finger across this line, you feel a definite ridge.

    The "after" joint produces a smooth, hazy feathering effect.

    One thing that wet-sanding does that dry-sanding does not do: it moistens dried mud compound, thus "re-activating" it and moving it to other parts of the wallboard.

    Continue to 6 of 6 below.
  • 06 of 06

    Drywall Wet Sanding Recap

    Drywall wet sanding infographic
    Lee Wallender

    In conclusion, a few of the positives and limitations of this process:

    Positives

    • Creates no drywall dust.
    • In some cases, smooths and rounds out deficiencies better than dry-sanding.
    • Few materials needed, just a sponge, bucket, and water.

    Limitations

    • Not practical for large areas.
    • Difficult to bring down high points without also affecting surrounding areas.
    • Makes the wall wet, which requires you to wait before you can prime the wall.
    • You cannot get a mirror-smooth joint by wet-sanding.