How to Sand Drywall

August 13th, 2009 by Mike

Finishing drywall can be a daunting task, with sanding the individual coats of mud being the most tedious. By employing a few tricks of the trade, sanding drywall doesn’t have to be a chore.

The first thing to understand is that overall, sanding has the greatest impact on your drywall project. If drywall sanding has been done carelessly, it will show. An even surface is necessary to ensure a smooth, defect free paint job.

In order to start sanding, you must first ensure that the joint compound or drywall mud is dry. If the joint compound is even damp, it will roll off in tiny balls rather than adhere to the joint to which it was applied. If you are not sure if the compound is dry, gently run a finger over the center of the seam, without applying pressure. If the compound’s temperature is cooler than that of the surrounding wall, it is still wet.

Next, make sure that you have all the proper tools. Install 120 grit sandpaper to a sanding block, or purchase a multi-grit sanding block. Make sure the sandpaper is flat with no wrinkles and purchase a extension pole if the job is large or up in higher areas. Make sure you have a dust mask or respirator, and goggles before you begin.

Use light, even pressure and slide the sandpaper across the entire width of the joint compound, especially at the edges, though more pressure is usually needed at the joint, where the compound is usually thicker and has more imperfections.

Sand every surface that has been treated with joint compound and gently run your hand over the surface to ensure it is smooth with the drywall. Low lying spots are generally not a problem as long as the layer you are working on is not the finish layer. Sometimes it is easier to identify problem areas by using a flashlight. Shine the beam flat across the surface of the wall and look for shadowing. This would indicate a high or low lying area. If imperfections in the joint compound are found, re-apply the compound and repeat the steps listed above.

Sanding drywall is best done by hand unless very large areas are to be sanded. Then it is advisable to utilize a power sander, but hand sand the finish coat. Many times it is easier to purchase pre-made sanding sponges that will allow you to sand in corners and around any trim or decorative accents, ensuring the most even results. This technique will provide you with the best opportunity to have a successful do-it-yourself drywall project with outstanding results.