Sanding drywall require the use of specific grit of sandpaper and specific tools to achieve a smooth drywall surface. Using the wrong grits of sandpaper too quick will lead to scratches on the drywall. Additionally, if you use sandpaper that is too coarse for the final stage of sanding, those coarse sandpaper scratches will be visible once the drywall is painted.
If the drywall isnt sanded proper, there will be the need to apply more paint or joint compound to hide the imperfection on the drywall. Coarse sandpaper or coarse sanding screen are used for the first stage of sanding drywall. Coarse sandpaper is used when the joint compound have ridges or lumpiness on the drywall.
How to Sand Drywall the Right Way
Coarse sanding screens are used for the first stage of sanding because the mesh screens allow the dusts created during sanding to pass through the sandpaper screen so the screen does not become clogged during sanding. Once the contractor has sanded the ridges of the drywall with coarse sandpaper, medium sandpaper should be used. Medium sandpaper is used to sand the edges of the joint tape so the joint compound blend into the drywall.
For the last and final stage of sanding, fine or ultra-fine sandpaper should be used. This stage of sanding ensure the drywall is smooth and ready to be treated with primer and paint. There are also different tool that can be used to sand drywall.
Tools include pole sander, hand blocks, and sponges. Pole sanders are used to sand large area such as ceilings and walls. Hand blocks are used for small patch of drywall.
Hand blocks allow the drywall contractor to feel the sandpaper pressure being applied to the joint compound. Sponges are helpful tool for drywall sanding because the sponge can conform to the corners of the drywall. Fine-grade sponges are used for the final sanding stages to sand the corners of drywall without flatten the corner edges.
Another important aspect of sanding drywall is the control of the dust that will be create during sanding. When drywall is sanded, a large amount of fine dust is created. This fine dust can enter the contractors lungs and settle on the drywall surfaces.
To control the dust, use a HEPA vacuum to clean up the drywall while using the sander. Use plastic sheeting to seal the drywall and sanding area to ensure the dust does not travel to other part of the house. Wear an N95 mask so the N95 mask protects the contractors lungs from the fine drywall compound particles.
It is also necessary to periodically inspect the drywall while sanding. Use a work lamp to inspect the drywall while sanding because the work lamp will cast shadow on any imperfections on the drywall. These shadows will indicate whether or not the drywall is smooth and ready for the next sanding stage.
Use overlapping circular sanding motion on the drywall so there are no linear marks on the drywall. Additionally, ensure that the joint compound has cured for the drywall to be sanded. Allow each coat of joint compound to dry for at least 24 hours before sanding the drywall.
Sanding wet joint compound will ruin the drywall surface. After sanding drywall, it is important to treat the drywall with primer. Using primer on drywall will fill in the micro-scratches of the drywall and reveal any flaw on the drywall.
Any flaws will require more joint compound to be applied and sanded. Following these stages and sanding the drywall with coarse to fine sandpaper will ensure drywall is smooth and ready to be paint.
