01 of 06
Materials Needed for Drywall Wet Sanding
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 it 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 is best, if the bucket has not contained caustic chemicals prior to your project.
- 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
Continue to 2 of 6 below.
- Soak a sponge in a bucket of warm water, then squeeze out.
- 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.
- 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.
- On this second pass, since you have already taken down the high ridges, you can concentrate on lowering the joint compound bump.
- 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.
02 of 06
Fill Water and Wring out Sponge
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 wringing 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
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
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
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
In conclusion, a few of the positives and limitations of this process:
- 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.
- 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.