Pre-plastered wallboard
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An alternative is presented to today's practice in construction of applying a thin layer of plaster to plasterboard or “blueboard”. In this invention, the inside or exposed surface of plasterboard or its equivalent is pre-coated with a relatively thin layer of plaster under controlled conditions at a remote location, such as a factory or other facility near or at the construction site, before the plasterboard is placed on the framing of the structure. The coating can then be cured under controlled conditions before the boards are installed on studs with fasteners, or adhesives. The seams between the boards may then be patched.

Ekchian, Gregory James (Belmont, MA, US)
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Gregory J. Ekchian (Belmont, MA, US)
The following is claimed:

1. - A method for improving the application of plaster to blueboard, the method comprising: applying a skim coat of plaster to blueboard prior to its installation.

2. - Method of claim 1 wherein the blueboard is placed in an orientation that is advantageous for the application of a skim coat of plaster.

3. - Method of claim 1 wherein the ambient conditions during application of plaster is controlled to levels that are advantageous for the application of plaster.

4. - Method of claim 3 wherein the ambient conditions that are controlled include at least one from the list of humidity and temperature.

5. - Method of claim 1 wherein the ambient conditions that are controlled during the curing of the plaster are controlled to levels that are advantageous for the curing process of the plaster.

6. - Method of claim 1 wherein the ambient conditions during the drying process are controlled to levels that are advantageous for the drying process.

7. - Method of claim 2 wherein the blueboard is placed in a horizontal position with the surface to be coated facing up during the coating process.

8. - An improved blueboard product comprising a precoated blueboard with a skim coat of plaster applied to the blueboard prior to installation.

9. - The product in claim 8 wherein the plaster is applied to the entire surface of the blueboard.

10. - The product in claim 8 wherein the plaster is applied selectively on parts of the blueboard.

11. - The product in claim 10 wherein the plaster is not applied to the edges of the blueboard.

12. - The product in claim 10 wherein a bonding material is applied to areas that are not coated with plaster to facilitate the subsequent application of patching compounds.

13. - The product in claim 8 wherein a bonding material is applied to the blueboard prior to, during or after the application of pre-coated plaster to improve the bonding of the plaster to the blueboard.

14. - The product in claim 13 wherein the bonding material is applied to the entire blueboard surface.

15. - The product in claim 13 wherein the bonding material is applied selectively to parts of the surface of the blueboard.

16. - The product in claim 15 wherein the bonding material is a mesh material.

17. - The product in claim 16 wherein the mesh material is metallic.



I hereby claim the priority of my earlier filed provisional application No. 60/659,920, with a filing date Of Mar. 8, 2005.

Starting in the 1940's, the use of traditional plaster walls was gradually replaced by the use of a gypsum based wallboard that has come to be called drywall.

Drywall today is manufactured by several manufacturers and commonly comes in sheets that are four feet wide and eight or twelve feet long and ½″ thick. These sheets of wallboard are typically attached to studs and joists to form walls and ceilings. The sheets are usually tightly butted against one another and the resulting joints are taped and filled with joint compound. Typically the entire surface is then primed and painted.

Using drywall is much less expensive than traditional plastering techniques such as, for example, where a relatively thick layer of plaster is applied to wood lath. However, such a primed and painted drywall surface is typically not considered to be as attractive or durable as a traditional plaster wall. It is not as hard a surface and is easily scratched or scored. Also, it is typically not as smooth or attractive as plaster walls. Furthermore, joints between the sheets of drywall are usually discernable even after painting.

There is an alternative approach that is currently in widespread use and offers the advantages of the smooth hard surface of a traditional plaster wall at a cost approaching the use of drywall. This alternative is to use a gypsum based wallboard similar to drywall, but by applying a thin skim (also called veneer) coating of plaster to it after they are installed.

A skim coat of plaster does not typically adhere well to conventional drywall unless it is primed by a special primer made for this purpose. Alternatively, skim coats of plaster can be applied to another type of gypsum based wallboard typically called blueboard. Blueboard, a type of wallboard, is similar to drywall except that the paper cover used on these boards is specially treated during manufacture so that the skim coat of plaster will adhere to it.

In a typical case, the blueboard is first installed on the framing (studs and joists). Then a crew of plasterers coats the surface of the wallboard with one or more thin layers of plaster. Blueboard is typically attached to wooden or metal studs (or joists) by nails, screws or other fasteners or adhesives.

Among the drawbacks of this approach is that specialized skilled labor is necessary onsite in significant numbers, and the ambient conditions (for example, temperature and humidity), the condition of the surface of the wallboard (exposure to dirt, liquids, etc.) cannot be controlled. Also the plaster frequently has to be applied at difficult angles or non-optimal positions. Under these conditions, it is very difficult to maintain a desirable plaster thickness and uniformity over the entire surface. It is further difficult to maintain desirable conditions during the curing and drying processes.

Because of the variability in the skill of the plasterers and conditions of the blueboard and conditions during application, curing and drying, results are frequently less than optimal and can vary greatly from site to site or even in a single site or building.


In this invention, the application of plaster or equivalent coating material that serves a similar purpose, is applied to the blueboard or other type of wallboard, under controlled conditions before it is mounted on walls, ceilings, or other surfaces in a house or other building. The plaster or other coating is applied under controlled conditions that improve the quality or ease with which the coating is applied. The pre-coated wallboard can then be allowed to cure and dry under controlled conditions, protected, packaged, transferred, and installed much like blueboard is handled currently.

Once on the job site, the wallboard is placed on desired locations in a home or other building. The pre-coated boards are attached to the surface by screws, adhesives, or other techniques or combinations that are appropriate. The wallboards can then be primed and painted and finished as necessary, although some of these steps can also be performed prior to the installation of the boards at the jobsite or a remote location.


FIG. 1 shows a wallboard coated with a layer of plaster.

FIG. 2 shows the elevation view of the precoated wallboard in FIG. 1.

FIG. 3 shows a wallboard that is precoated over most of its surface. A strip around the perimeter is uncoated.

FIG. 4 shows the elevation view of the wallboard in FIG. 3.

FIG. 5 shows a precoated wallboard as in FIG. 3. In this embodiment the uncoated area around the perimeter is covered with a mesh material that overlaps the edges of the wallboard.

FIG. 6 shows an elevation view of the wallboard in FIG. 5.


In a preferred embodiment of this invention, plaster or other desired coating is applied to the blueboard or equivalent before it is mounted on desired surfaces in a house, or other site. The coating can be applied under controlled conditions such as temperature and humidity. These conditions can be held constant or varied during the application or curing and drying processes or both. For example, the humidity may be maintained at an elevated level until curing is completed and then lowered to allow for optimal drying. The environment can also be controlled to remove dust, chemicals or other harmful materials.

The entire surface of the blueboard 2 may be coated with plaster 1 as shown in FIGS. 1 and 2. Alternatively, portions of the blueboard, for example, areas along the edges 5, may be kept substantially free of plaster as shown in FIGS. 3 and 4. These areas could then be coated with plaster, or a patching material such as joint compound, after the boards are installed at the job site. In this way, the joints between pre-coated blueboards can be patched so that a continuous wall surface is achieved.

Areas such as the edges of the plasterboard 6 that are not pre-coated plaster may have material 8 added, as shown in FIGS. 5 and 6, such as plaster tape or a mesh material, to facilitate the covering of joints between boards. The remainder of the board would be covered with plaster 6.

In a further embodiment of this invention, material can be added to the board, for example prior to the application of the plaster, to facilitate the repair of damage to the plaster surface during the mounting process. This material could be a solid or liquid during application. For example, a mesh, similar to joint tape or a metal mesh, can be applied to all or part of the surface of the blueboard before, during, or in certain cases after, the plaster is applied. This would strengthen the bond between the plaster or the patching material and the blueboard, reduce the chance of cracking and facilitate repair of chips or screw holes and the like after installation.

In the methods and products described herein, blueboard can be replaced by other gypsum-based boards or other types of wallboard that can be coated with plaster before being installed as walls or ceilings and the like. Plaster can also be replaced by other coating materials that can be applied to wallboard and that serve similar function served by plaster today in the construction of a wall, ceiling or other such surface. It is also noted that the fabrication process of the wallboard can be altered so that it can be pre-coated with plaster during the fabrication process of the wallboard.

The invention has been described in terms of its functional principles and several illustrative embodiments. Many variations or modifications in the illustrative embodiments will be obvious to those skilled in the art. Accordingly, it should be understood that all such variations and modifications are intended to be covered by the ensuing claims as well as all equivalents thereof.