How To Paint Level 5 Walls

Drywall installation in gymnasium

Based on the feel of Paint Quality Assurance inspector Dave Lick

Question: can an ASTM Level 5 Drywall Finish produce a satisfactory painted cease in disquisitional lighting areas and/or when using higher sheen paints?

Answer: it depends. It depends on a diverseness of factors — including whether or not yous ask a painter or a drywall finisher.

Hither'southward a history lesson: not so very long ago, walls finished with an ASTM Level 4 Drywall Finish could exist finished with one coat of latex sealer followed by a very different intermediate than we commonly utilise today; namely, an enamel (alkyd) undercoat such as the products canonical under MPI #46.

This enamel undercoat was thick enough to mask fine surface irregularities and fill up the paper texture. It was inexpensive and offered the boosted benefit of being sandable, versus the latex intermediates nosotros use today that don't vitrify down like an alkyd can.

That enamel undercoat could then exist topcoated with an eggshell or semigloss alkyd, especially on walls discipline to abrasion, marking, or wet areas (bathrooms, showers, janitor closets) — and there was no discussion of texture imperfections telegraphing through the surface.

Flash forward to today: alkyd undercoat enamels are, in our experience, virtually never specified for new construction products, and a sandable, cheap, VOC-compliant replacement does not appear to be. And regulations accept moved the industry to almost eliminate alkyds for interior walls, replacing them with multiple coats of latex at a college cost and lower volume solids, which means less material is deposited to smooth out the surface.

The ASTM Level 5 Drywall Terminate

So now, we specify a Level 5 Drywall Terminate to guarantee an adequate surface in areas of critical lighting or where a glossier finish is required. And although Level 5 consistently provides ameliorate results than Level four, unfortunately information technology's no guarantee of a perfect finish.

Here'southward the defining clause in a Level 5 Drywall End as described in ASTM C840's Standard Specification for Application and Finishing of Gypsum Lath: "A thin skim coat of articulation chemical compound shall be trowel-applied to the unabridged surface. Backlog chemical compound is immediately sheared off, leaving a film of skim coating compound completely covering the newspaper. As an alternate to a skim coat, a material manufactured peculiarly for this purpose shall exist applied."

So yes, a properly-executed Level v cease will eradicate the drywall paper texture — just in that location'south a popular misconception that it can too repair 'proud' or 'poor' seams, humps and bumps, or other defects. Contrary to popular thinking, it cannot. Level 5 tin't level the surface of the wall or eliminate many of the defects that obviously bear witness in critical lighting areas, or where higher gloss finishes are used.

In fact, the ofttimes-cited Gypsum Association'due south GA-214-10e Recommended Levels of Gypsum Board Terminate says that "the Level v end is highly recommended where paint is specified or where astringent lighting weather occur" and that it'south the most effective method to minimize visible defects — simply the guide also warns that "a skim glaze volition not approximate a plastered surface. Once the skim coat dries, the gypsum lath paper may evidence through and the treated joints, filled voids, and spotted fastener heads will likely be visible."

And so essentially, the Level v 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 exist 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. At that place is no specific mil thickness that constitutes a proper skim coat."

The quality of the skim coat may also depend on how information technology 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 articulation compound be such that it can be applied by a trowel. Other tools may be used for application so long equally the trowel consistence is achieved."

And in fact, with the joint compound skim glaze materials currently on the market, there are iii means to apply them:

Troweled on: this is the slowest and well-nigh labor-intensive method, simply information technology 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 fabric on top of the seams or repaired areas is likely to create humps.
Roller application: drywall surfacing compounds are also available for roller awarding; withal, most drywall finishers do not have the roller skills and feel that painters typically possess, and so all the flaws mutual to roller application may prevail, including skipping, roller tracking, and an uneven surface. Also, application with rollers tends to comprehend the seams too equally the newspaper, which contributes to a more uneven appearance.
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 big surface area fairly quickly — notwithstanding, there are substantial drawbacks. Adhesion may be compromised; information technology's not unusual for these compounds to readily come up off when you endeavor to sand them. Air entrapment can likewise be a problem, as can heavy buildup in some places and non plenty in others, "fingering," and other flaws typical of unskilled airless spray piece of work.

When using roller- and spray-applied surfacing compounds, nosotros likewise come across bug with sanding: the material is very dry and powdery, and later 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 heed, thankfully a lot of drywall finishers won't accept roller or spray application for skim-blanket drywall surfaces.

Level 5 versus Level four

So what's the solution? If we can't have our former sandable undercoat enamel back with an acceptable VOC (and at a comparable toll), and considering the surface irregularities that may even so be present with Level five finishing, the intrepid inspector has found that for critical lighting areas and/or where a higher-sheen cease is required, requiring a Level v Drywall Stop may not be the most cost-effective solution afterwards all – and in our experience, it's rarely specified anyway.

Instead, comparable results may be achieved over a Level iv drywall finish by finishing the surface with drywall primer plus three coats of latex instead of the customary ii. Adding the 3rd coat of stop puts another one.v – 2 mils DFT of pigment on the surface and can make the departure between "unacceptable" and "acceptable." You'll see this yourself in repainting operations: a surface that was initially painted with a primer plus ii coats that looked "okay" but not great will often await a whole lot better later on its first repaint, when an boosted two coats are applied.

Stay up-to-date on manufacture best practices and trends with Free MPI Updates