Perforated Wallcoverings:
The OMNOVA Process

OMNOVA’s perforation process uses a custom, heated pin roller system which melts the wallcovering to create permanent holes in the product. Unlike some competitive perforation methods which use mechanical punching, OMNOVA’s holes cannot be obstructed or closed due to leftover vinyl flaps or chads.

Above: Micrograph of OMNOVA's Perforated Wallcovering

Note on the micrograph above how evenly the holes are perforated.  Consistent, even spacing of perforations are an advantage of OMNOVA's perforation process.

The holes created by the OMNOVA system do not affect the aesthetics of the wallcovering and are nearly invisible to the naked eye when the wallcovering is installed, yet provide a porous surface with permeability similar to some paints.
When properly installed and maintained on a permeable wall, OMNOVA’s perforated wallcovering will have significantly greater permeability than conventional vinyl wallcovering.

As with other building products, the successful use of vinyl wallcovering, either conventional or perforated, requires consultation with an experienced building professional who is familiar with the design and condition of the specific building, local conditions and the characteristics of vinyl wallcovering.

Peforated Wallcovering.
Comparing Permeability.

Permeability is a measure of the amount of water vapor (moisture) that can pass through a specified area of material in a certain amount of time. The measure and degree of permeability is expressed in units referred to as Perms. Materials with higher Perm levels allow more moisture or water vapor to pass through than those with lower Perm values.

While the construction industry has yet to recognize a single test procedure, the ASTM E-96-00 Standard Test for Water Vapor Transmission of Materials is being used by many companies to measure the permeability of their products; permeability values can vary substantiality depending on the test method used. Also, testing results can vary widely unless a strictly controlled and consistently applied test protocol is followed. There are several ASTM E-96 test procedures but the most commonly used test is the water cup (wet cup) method which tests for the permeability of the wallcovering itself (film and backing).

Using this ASTM test method, wallcovering perforated using the OMNOVA perforating system achieved the following permeability levels (an average of samples taken across the web of a roll of perforated wallcovering):

• Type I medium emboss with woven or nonwoven backing: 37 to 47 perms
• Type II medium emboss with Osnaburg backing: 37 to 45 perms

While these Perm values can provide general guidance, testing the permeability of a particular wallcovering construction under controlled laboratory conditions does not account for the many variables that can affect wall system permeability under installed building conditions.

The following graph compares average Perm levels between high quality OMNOVA perforated wallcovering and competitive perforated wallcovering as shown by outside third party testing:

The actual permeability of any particular perforated wallcovering will be impacted by the thickness or weight of the wallcovering, the specific type of embossing and the type of wallcovering backing. In addition, the permeability of an interior wall (without wallcovering) can be affected by several factors, including wall construction, wall conditions and wall surface preparation (including the type, thickness and number of layers of paint or primer). If a wall already has low or no permeability, then installing perforated wallcovering will not provide any permeability benefit to the wall system. Some manufacturers will recommend a new wall surface be left unprimed to improve the permeability of the wall system. This may increase the overall permeability but may create other difficulties when wallcovering is removed or replaced.

Perforated Wallcovering.
Selection.

An experienced building professional familiar with the condition of the specific building, local conditions, and the characteristics of wallcovering should be consulted to determine if perforated wallcovering is right for your application. If your building professional determines that a permeable interior wall system is appropriate, interior walls (particularly older walls) should be tested for permeability prior to installation of perforated wallcovering.

While perforated wallcovering will maintain many of the functional qualities of conventional vinyl wallcovering, perforated wallcovering will not be as cleanable, durable or protective as conventional unperforated wallcovering and, due to its higher permeability, will not prevent liquid or vapor moisture originating from the interior of the building (e.g., bathrooms, kitchens, etc.) from going through the wallcovering into the wall and wall cavity. Excellent cleanability/scrubability characteristics as well as protecting walls from interior liquid or vapor moisture intrusion, are important requirements in many applications.

Neither perforated, nor any other type of wallcovering, will prevent mold or other moisture related damage if a wall or wall cavity is subject to moisture accumulation. If moisture is present for a sufficient period of time, mold will form regardless of whether the wall surface treatment is paint, perforated wallcovering or other material. Prompt correction of moisture sources is always required. Building maintenance must always include actions necessary to prevent the development of moisture accumulation sources as well as routine inspections for and prompt corrective action if moisture accumulation is found in a wall or wall cavity.

information herein courtesy OMNOVA WALLCOVERINGS