Expansible Reveal With Frontal Tear Strip For Plaster Walls

Abstract

An extruded generally T-shaped separator or screed is tacked along the wall base with the center leg projecting outwardly. Plaster is applied to the wall base to interlock opposite sides of the screed leg. The screed leg is itself hollow, the frontal exposed side being a tear strip finally removed to form a reveal, and the rearward side being bowed or sinuous to form an expansion mechanism. As the plaster expands and contracts transversely to the screed leg, the reveal opens and closes correspondingly without any separation of the leg sides from the respective sections of the cast wall.

Description

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to wall construction, and more particularly, to a screed forming a decorative expansible reveal between adjoining sections of a plaster or other cast wall.

2. Discussion of Prior Art

For a variety of reasons, plaster and other cast walls expand and contract to a considerable degree long after the cast wall is cured. A chronic cause is temperature change. Another cause in high structures is flexure due to wind loading. Seismic disturbances are acute causes. Irregular cracks can be minimized by dividing the cast wall into sections as by the use of divider members such as a strip or a channel. But in this instance, an unsightly slit may open between the side of the divider member itself and the side edge of the cast wall. Expansion of the cast wall may not be properly tolerated by such separator strips.

A neat joint between the side of the divider member and the abutting surface of the cast material is difficult to achieve. The plaster or other material tends to splash over the divider member.

To achieve a neat finished appearance when a solid strip is used as the divider member, the divider member should be wiped clean before the splashed over material cures, because removal after curing results in pulling away patches of the plaster on the finish side. This, of course, is tedious and thus economically unsound.

If a channel is used as the divider member, sharp edges at the channel sides may provide a sufficient discontinuity to prevent any bonded juncture between the splashed over material and the plaster on the finish side. However, the channel will have to be cleaned later with consequent penalty as to cost.

Another solution is to apply masking tape over the solid separator or channel separator. This usually results in pulling patches of material from the finished side. Applying the tape is also time consuming.

BRIEF SUMMARY OF THE INVENTION

The primary object of this invention is to provide a simple screed that forms a decorative expansible reveal free of the foregoing disadvantages. For this purpose, I provide an extruded separator or screed of hollow generally rectangular configuration. The front wall is joined to the side walls by thin fracture webs. The webs are so located as to form small sharp V-grooves, the webs being located at the troughs of the grooves with the side edges of the front wall forming the inner sides of the V-grooves and the side walls of the screed forming the outer sides of the V-grooves. The front wall forms a tear strip removed after the plaster is set. A clean reveal remains. Any splashed over plaster entering the V-grooves is neatly broken away as the tear strip is removed. Attaching flanges form lateral extensions of the rear wall of the screed. The rear wall is curved, sinuous, or otherwise non-linearly formed to allow the side walls to move toward and away from each other as the cast wall expands and contracts.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of the invention will be made with reference to the accompanying drawings. These drawings, unless described as diagrammatic or unless otherwise indicated, are to scale.

FIG. 1 is a pictorial view of a length of an extruded separator or screed incorporating the present invention.

FIG. 2 is a view similar to FIG. 1 but showing the separator installed.

FIG. 3 is a sectional view taken along a plane corresponding to line 3--3 of FIG. 2.

FIG. 4 is a sectional view similar to FIG. 3 but illustrating a separator having a different reveal size.

DETAILED DESCRIPTION

The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention since the scope of the invention is best defined by the appended claims. Structural and operational characteristics attributed to forms of the invention first described shall also be attributed to forms later described, unless such characteristics are obviously inapplicable or unless specific exception is made.

The separator or screed shown in FIG. 1 is a one-piece extrusion of generally T-shaped configuration. A wide variety of plastics or other materials may be used. Preferably the plastic is flexible and soft enough to permit it to be readily cut to length and to be nailed in place. Polyvinyl chloride fulfills the requirements.

The center leg of the T-shaped separator is itself a hollow four-sided structure, there being opposite parallel side walls 10 and 12, a front wall 14 and a rear wall 16. Extending laterally from the corners at the rear wall are attaching flanges 18 and 20. These flanges may be tacked to the lath W or other wall base upon which plaster or other cementious material is intended to be cast. Holes 24 for the tacks may be provided if desired.

The side walls 10 and 12 are designed to form edging for the opposed ends of the plaster slabs or wall sections A and B cast on the wall W. The outer ends of the side walls 10 and 12 are inwardly beveled as at 22 and 23 so that the ends of the walls 10 and 12 terminate at sharp edges. The ends of the front wall 14 are similarly inwardly beveled as at 26 and 28. Accordingly, frontally facing shallow V-shaped grooves 30 and 32 are formed.

The front wall 14 is substantially flush with the edges of the side walls. The thickness of the front wall 14 only very slightly exceeds the depth of the V-grooves 30 and 32; the front wall is thus joined to the side walls 10 and 12 only by a thin fracture web.

The wet plaster is applied to the wall W with a thickness equal to the dimension of the separator side walls 10 and 12. The separator forms a ground along or across which a feather edge may be moved. Laterally extending interlock flanges 36 and 38 extend outwardly from the side walls 10 and 12 to provide a firm connection.

Some of the plaster material may enter the V-grooves 30 and 32. This excess will then be joined, if at all, to the main body of the plaster sections A and B only by an extremely thin readily frangible web. After the plaster is set, the front wall 14 is torn away as indicated by the arrow 40 (FIG. 2). Any material in the V-grooves 30 and 32 is clearly carried away with the tear strip or front wall 14. A neat, clean reveal accordingly remains.

Upon expansion and contraction of the slabs A and B, the side walls 10 and 12 move correspondingly, being anchored to the respective slabs by the T-head interlock flanges 36 and 38. This movement further is ensured by the inwardly arched configuration of the rear wall 16. No unsightly crack develops between the side walls 10 and 12 and the corresponding surfaces of the plaster material.

In the form shown in FIG. 4 a similar arrangement is provided in which the screed has different proportions. In this instance, the reveal is wider. Hence, the degree of bowing of the rear wall need not be so great to allow the same expansion.

Claims

I claim:

1. In a wall structure including a support and a pair of separate slabs of plaster-like material cast in situ on said support, the combination therewith of a unitary elongated expansible hollow separator between said slabs:

a. said separator having a front wall, a rear wall and opposite side walls;

b. said rear wall including a pair of planar flanges for attaching said separator to said support with said front wall facing outwardly, said flanges respectively extending laterally in opposite directions, said side walls serving as screeds to establish the thickness of said slabs;

c. the center portion of said rear wall being inwardly arched to allow movement of said side walls toward and away from each other in response to expansion and contraction of said separate slabs;

d. said front wall being joined to the side walls by fracture webs of thinner cross-section than said front wall whereby said front wall forms a tear strip removable after said slabs are formed, said fracture webs being defined by inwardly beveled outer ends of said side walls, said front wall being substantially flush with said side wall outer edges so that upon removal of said front wall said separator is exposed only at the region of its hollow interior; and

e. each said side wall being provided with an anchor means disposed intermediate said front and rear walls and extending laterally outwardly from that side wall, the outer end of each anchor being a T-head locking the side wall to its associated slab for conjoint movement therewith.