A curved wall system. Canned ceiling lights create critical lighting shining down on walls.

Drywall is drywall is drywall-or so they say. In the gypsum board business, there are eight different manufacturers that produce drywall from more than 75 plants in the United States. Drywall comes in a variety of flavors that perform admirably in nearly any wall and ceiling system.

The industry produces 1/2-inch regular wallboard which is used primarily in residential construction; 5/8-inch wallboard is used mostly in commercial construction and/or fire-rated system assemblies, boards for ceiling systems and boards for wall systems.

A shopping mall with skylights. These types of applications must be finished to a Level 5 to minimize the effects of critical light on walls.

There are also gypsum board products designed for a specific purpose, such as abuse resistance, impact resistance, abrasion resistance, moisture resistance, mold resistance, and more. But there is one thing these board products all have in common-they all must be finished. If you want your walls and ceilings to look great after decoration, the secret is in the finishing process.

Architectural design has changed dramatically since the ’50s and ’60s, when homes and offices were built with relatively small and fewer windows. Since that time, architects have beautifully brought the outdoors inside our homes and office buildings with extensive use of windows. This change is one that we have all embraced. More and larger windows bring nature and warmth that we all can enjoy. Window walls in residential and commercial construction have become the norm rather than the exception.

Advancements in paint technology have also come a long way in the past 50 years. We now have the choice as to whether we want to decorate with textures, flat painted walls and ceilings, or if we prefer, gloss-type paints such as eggshell, semi-gloss or even very high-sheen high-gloss paints. These paints offer great maintenance value, as they’re easy to wipe down with mild soap and water.


So, we now have the new window-wall designs with oblique lighting effects. The critical lighting angles coupled with the sheen from paints create havoc with all board products and finishes. All of this creates a finishing problem for the drywall contractor.

Every one of the wall and ceiling board products mentioned previously must be finished with joint treatment to a level specified by the architect. Joint treatment manufacturers have all created products that perform exceptionally well for finishing these board products. When specified and applied properly, the finish is designed to achieve a surface that will receive a specific decoration.

The proper joint treatment finishing of drywall will minimize the effects of critical lighting and gloss paint products. It will also minimize paper irregularities that naturally appear when exposed to critical light conditions.

We must all remember that drywall is just a substrate. It is not a finished product. No one would leave drywall unfinished in a home or office building. Drywall must be finished with joint treatment to fill all joints, fastener recesses and when recommended, the entire surface of the wallboard (Level 5) to minimize the effect of critical lighting and gloss paints. After all, the surface is made of paper. Even paper has a texture and irregularities in it that will appear when critical lighting and/or gloss-type paints are used for decoration. The secret is finishing the drywall with joint treatment that will prepare the substrate to receive the decoration desired by the architect and/or building owner.

In 1990, the Gypsum Association published an industry recommendation called “Recommended Levels of Gypsum Board Finish (Document GA-214).” The original recommendation has evolved and today has become an industry specification by ASTM International. It is imperative that these documents be incorporated into architectural specifications, followed through the bid process and implemented by the drywall contractors if the building owner is to be satisfied with the appearance of their walls and ceilings.

Window walls create critical lighting conditions.


In 1992, a new organization called the Drywall Finishing Council was founded. This not-for-profit organization was assembled to represent manufacturers of joint treatment products and the issues that are commonly faced with joint treatment products in the field. The organization’s members are manufacturers of joint treatment products and raw material suppliers used coast to coast. They are dedicated to developing industry standards for joint treatment use and application procedures. This is an industry group that works closely with raw material suppliers, manufacturers of joint treatment products, drywall finishing contractors and paint manufacturers collectively to develop industry documents supporting better finishing processes. Ultimately, the DWFC aims to improve and raise the level of drywall finishing.

This room is very dark with dramatic colored paints on the wall and critical light conditions. Without a Level 5 Finish, drywall joints, fastener heads and/or any other problems would be revealed.

The council supports the Recommended Levels of Gypsum Board Finish established by the Gypsum Association. Beyond the levels of finish, the DWFC has published a document titled, “Recommended Surface Treatment for Finishing Gypsum Panels to Attain a Level 5 Finish.” This document describes guidelines for determining the visual performance expectations of a Level 5 finish. In essence, the recommendation outlines performance expectations and also recommends the construction of a job site standard in advance of work. This job site standard will establish a level of visual appearance deemed acceptable. When a job site standard is established it will eliminate problems during construction when a critical lighting and/or gloss type paint decoration is applied.

It seems that some home builders and general contractor inspectors want to use a halogen light source to shine obliquely over walls after they have been finished and painted. They use this process to look for possible “defects” in materials and/or workmanship by the drywall contractor. The contractor is then contacted and charged with “making repairs.”

Window walls with high gloss paint.

This is hardly a realistic inspection process and totally inappropriate to expect finished wallboard surfaces to look like a sheet of glass. Finished wallboard surfaces actually create an “illusion of flatness.” Walls and ceilings are not actually perfectly flat. Even a Level 5 finish will only “minimize” critical lighting and gloss paint issues. It’s unrealistic to expect that any finished drywall will completely eliminate surface problems. It’s unfair for the contractor to be charged with “making repairs” when this type of inspection process is employed.

High-gloss finish paints on the columns, which are wrapped with gypsum boards.

Walls and ceilings should be inspected utilizing the light source that will be used when the building is occupied. Since the greater percentage of buildings use normal ceiling lights, this would clearly be the better choice. The document titled “Method for Inspecting Interior Joint Treated Gypsum Panel Surfaces” is available from the Drywall Finishing Council. It can be found on its Web site for free atwww.DWFC.org.

We are all in this business to produce quality work that will satisfy our customer, the building owner. Everyone involved in the building process from specifications to decorated product, must work together to satisfy the building owner. As we all know, the secret to great looking walls and ceilings … is in the finishing. W&C