Whenever sanding smooth walls it is important to use a halogen light with a 500 watt bulb aimed along the surface being sanded.
This is also why tightly skimming the surface is important in step 3. If too much material was left when skimming it can require more sanding due to a greater possibility of imperfections in thicker mud. A light brushing using 150 grit sandpaper on a sanding poll is usually sufficient. A halogen light with minimum 500 watts power aimed along the surface is necessary to see any imperfections that were not covered by roll skimming. Once dry, a light sanding is necessary to remove any minor imperfections. The diagram illustrates the concept while the photo demonstrates how the seam was pulled in one direction and currently the field is being pulled into where the seam was just finished. Rolled mud on seams (joints where two bound edges meet) should be pulled in the same direction that they run along a sheet of drywall. The "field" (where screw heads are coated and the majority of area is simply drywall paper) should be pulled perpendicular to the seams and incidentally parallel with butt joints (joints where two cut edges meet). Mud should be pulled in two different directions. The knife is bent gently with pressure applied to the right side of the knife therefore slightly floating the edge of the mud so as not to leave tool marks.Īlso important is the direction that you pull the mud when skimming. This side of the knife is not touching the surface. Also notice the arrow pointing to the left side of the knife. A high angle in relation to the drywall surface will remove more mud, leaving behind only a very thin layer. Notice in the picture below the angle of the knife as it pulls mud from the surface.
The angle to hold the drywall knife is important. Rather, roll skimming works mud into the pores of the drywall paper making the "field" of similar consistency to that of seams, joints and screw heads. It is not as if you are floating the entire surface being skimmed. However the key to roll skimming a wall is not leaving excess mud on the surface. You may feel that removing so much material will negate the benefit of applying a thin layer of mud to the surface. The angle of your knife to the drywall surface as well as pressure used is similar to that used when coating screw heads. This is different than the technique used when coating drywall joints. The drywall knife should be pulled tightly across the surface you are skimming. Using a twelve to fourteen inch drywall knife, remove as much drywall compound as you can. Step 3 - Skim the surface with a large drywall knife The goal is to have mud thin enough that can be rolled smoothly with a paint roller. Once the paddle spinning creates a vortex that extends half way down the mud it is considered thin enough to roll.
Others watch the paddle as it spins in the bucket of mud. Some use their drywall pan to measure out water. To test for desired consistency, tradesmen use various techniques. Water should be added to drywall joint compound gradually until the desired consistency is achieved. Only texture mud may be thinner depending on the type of texture applied. Mud used for roll skimming is nearly the thinnest mud used for any step of the finishing process. Some tradesmen however prefer to use "topping" compound because it creates a harder surface than "all purpose" mud which may reduce (though slightly) denting in the finished surface. Tradesmen will many times prefer to use lightweight all purpose joint compound because it is easier to sand than "all purpose" or "topping" compound and a light sanding is required once dry. Any type of drywall compound can be used when roll skimming.
Best drywall compound for skim coating how to#
How to Skim Drywall for Smooth Walls What kind of mud should be used?Īccording to GA-214-10, a thin layer of joint compound should be trowel applied.
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