Fine Finish by CHEETAH CONSTRUCTION INC.

The ASTM Level 5 Drywall Finish
 

Here’s the defining clause in a Level 5 Drywall Finish as described in ASTM C840’s Standard Specification for Application and Finishing of Gypsum Board: “A thin skim coat of joint compound shall be trowel-applied to the entire surface. Excess compound is immediately sheared off, leaving a film of skim coating compound completely covering the paper. As an alternate to a skim coat, a material manufactured especially for this purpose shall be applied.”
 

So yes, a properly-executed Level 5 finish will eradicate the drywall paper texture — but there’s a popular misconception that it can also repair ‘proud’ or ‘poor’ seams, humps and bumps, or other defects. Contrary to popular thinking, it cannot. Level 5 can’t level the surface of the wall or eliminate many of the defects that plainly show in critical lighting areas, or where higher gloss finishes are used.
 

In fact, the often-cited Gypsum Association’s GA-214-10e Recommended Levels of Gypsum Board Finish says that “the Level 5 finish is highly recommended where paint is specified or where severe lighting conditions occur” and that it’s the most effective method to minimize visible defects — but the guide also warns that “a skim coat will not approximate a plastered surface. Once the skim coat dries, the gypsum board paper may show through and the treated joints, filled voids, and spotted fastener heads will likely be visible.”
 

So essentially, the Level 5 drywall finisher is telling the painter “the paper texture may be eliminated but other abnormalities or variations [which we in the painting industry would call ‘defects’] may still be present."
 

Issues with Skim Coating
 

The overall quality of the skim coat plays a substantial role. First, no specific mil thickness is specified in the standard. GA-214-10e points out “a skim coat is essentially a ‘film’ of joint compound and is not a readily measurable thickness. There is no specific mil thickness that constitutes a proper skim coat.”
 

The quality of the skim coat may also depend on how it was applied. Even though the ASTM standard says “trowel applied,” GA-21-4-10e cautions that “a skim coat is described as trowel-applied with the intent that the consistency (viscosity) of the joint compound be such that it can be applied by a trowel. Other tools may be used for application so long as the trowel consistence is achieved.”
 

And in fact, with the joint compound skim coat materials currently on the market, there are three ways to apply them:

1. Troweled on: this is the slowest and most labor-intensive method, but it effectively accomplishes what a Level 5 should do. The trowel allows a skilled applicator to create a level surface by applying an appropriate amount of material to the paper areas only, since adding more material on top of the seams or repaired areas is likely to create humps.
2. Roller application: drywall surfacing compounds are also available for roller application; however, most drywall finishers do not have the roller skills and experience that painters typically possess, so all the flaws common to roller application may prevail, including skipping, roller tracking, and an uneven surface. Also, application with rollers tends to cover the seams as well as the paper, which contributes to a more uneven appearance.
3. Spray application: some drywall surfacing compounds are now available for airless spray application. This can be a very efficient — a big airless sprayer can cover a large area fairly quickly — however, there are substantial drawbacks. Adhesion may be compromised; it’s not unusual for these compounds to readily come off when you try to sand them. Air entrapment can also be a problem, as can heavy buildup in some places and not enough in others, “fingering,” and other flaws typical of unskilled airless spray work.

When using roller- and spray-applied surfacing compounds, we also see issues with sanding: the material is very dry and powdery, and after sanding, the paper texture often shows through, which essentially eliminates the value created by applying the skim coat in the first place.
 

With these issues in mind, thankfully a lot of professionals won’t accept roller or spray application for skim-coating drywall surfaces. 

Now that a Level 5 Drywall Finish has been specified, unfortunately it’s no guarantee of a perfect finish and is very labor extensive.

($$$$$)

s/ Paint Info.