Title:
Plaster baseboard
United States Patent 2237195


Abstract:
This invention relates to new and useful improvements in building materials and more particularly to plaster baseboard of fibrous or other material. Composition plaster baseboard of fibrous or other similar materials has, to substantial extent, superseded the use of wooden lath in present...



Inventors:
Piquet, Henry W.
Application Number:
US30485039A
Publication Date:
04/01/1941
Filing Date:
11/16/1939
Assignee:
MACANDREWS & FORBES COMPANY
Primary Class:
Other Classes:
52/310
International Classes:
D21J1/00
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Description:

This invention relates to new and useful improvements in building materials and more particularly to plaster baseboard of fibrous or other material.

Composition plaster baseboard of fibrous or other similar materials has, to substantial extent, superseded the use of wooden lath in present day building construction due to the lesser amount of time, and hence lower labor cost, required to apply it, the lesser amount of plaster required properly to cover the board, and also the fact that when installed such board provides a certain degree of both thermal and sound insulation, Plaster baseboard-of the type here involved is usually furnished in sections or pieces approxi- 15 and mately 48 inches long by 18 inches wide by 1/2 inch thick and is applied to the vertical wall and ceiling studs with its long dimension horizontally disposed, the sections or pieces being staggered alternately with respect to each other over the wall area. While the use of wall or plaster baseboard of this type embodies and is characterized by the several advantages and benefits set forth above, the use of such board prior to the present invention has presented one particular problem caused by the fact that these boards to a certain extent absorb and take up the moisture from the atmosphere or from plaster when it is applied to the surface thereof, This tendency for the board to absorb and take up moisture from the wet plaster coat or from the atmosphere causes the board to swell slightly and since these boards are placed in abutting relation with adjacent boards they cannot expand in the plane of the wall and therefore have a tendency to bulge away from the wall. The extent of the bulge is, of course, actually very allll but is enough sufficiently to displace the plaster coat so that when the plaster and board dry out the incidental contraction of the board causes the plaster coat to crack along the longitudinal joints between vertically related boards. This tendency for the plaster to crack is particularly prevalent in low-cost or "shoe-string" building operations where the plaster is usually of a poor mix and applied in as thin a coat as the contractor believes will pass a casual inspection, With the foregoing in mind, the object of the present invention, therefore, is to provide a plaster baseboard of fibrous or other similar materials which is constructed and arranged so that expansion and contraction of such board will take place in the plane of the board and entirely within the boundary thereof thus eliminating distortion of said board from its normal configuration and position and the resulting tendency for the plaster to crack along the longitudinal joints or seams between adjacent boards.

This and other objects and the features and details of the construction and function of the invention are hereinafter fully set forth and shown in the accompanying drawing, in which: Figure 1 is a view in perspective of a plaster board made according to the present invention.

Figure 2 is an enlarged partial view in section taken on line 2-2, Figure 1.

Figure 3 is a fragmentary view in perspective partially in section showing a portion of a wall surface composed of boards shown in Figure 1; Figure 4 is a view in plan of a board embodying a modification of the present invention.

Referring now more particularly to the drawing, reference numeral I designates a piece or section of plaster baseboard made of fibrous or other similar material. As shown, these pieces or sections of board are approximately three times as long as they are wide and are generally produced commercially in lengths of forty-eight inches, or three times the conventional spacing of the vertical wall studs 2 of a building, so that each board will extend over four such studs as shown in Figure 3 of the drawing. The boards are usually secured to the wall in staggered relation with respec to each other as indicated, and a con tinuous fiat surface is provided thereby to receive tinuous flat surface s provided thereby to receive usual one or more coats of plaster applied in the usual manner.

As shown in the drawing, one edge of each board I may, if desired, be provided with a V- or other shaped tongue 3 in which event the opposite edge thereof is provided with a correspondingly shaped groove or recess 4 arranged snugly to receive the tongues 3 of other boards thus permitting the boards I to be applied to the wall studding in interlocked abutting relation to form a continuous flat wall surface..

In order to accomplish the essential purpose of the present invention the opposite faces of flat surfaces la and Ib of the board I are provided with a plurality of equally spaced parallel slits 5 which extend longitudinally throughout the entire length of the board, although they may, if desired, extend either diagonally or transversely of the board. These slits 5 have a depth of approximately one-half the thickness of the board and those in one face or surface of the board are preferably arranged in alternately staggered relation with respect to the slits in the other or opposite face or surface of said board as illustrated in Figures 1 and 2 of the drawing.

By providing the faces of the board with scores or the like 5 arranged' as above described, the said board is structurally weakened in.its plane surface portions and an accordion-like action takes place within the board which provides sufficient space for maximum expansion of said board in its own plane and within its normal border limits with the result that no bulging or other distortion of the board occurs because of any swelling of the board due to the absorption of moisture from a wet plaster coat or otherwise. Hence, any tendency for a plaster coat applied to the board surface to crack at the longitudinal seams between adjacent boards because of contraction upon drying is substantially entirely eliminated.

The slits 5 are not intended to receive a portion of the plaster applied to the surface of the board and do not therefore function to hold or "key" the plaster thereto since the filling of said slits I with plaster would not leave the requisite space to take up swelling and expansion within the board, and the specifically intended function or purpose of providing the slits would be defeated. To this end, therefore, the slits I are essentially of a width narrow enough so that in the normal application of a plaster coat little or no plaster will lodge therein, and in practical form of the invention these scores or grooves 5 have a width of less than one thirty-second (A) of an inch., In lieu of providing the board with slits 5 which extend continuously between opposite edges of the board, it may be desirable, in the interests of somewhat greater strength, to arrange the slits as shown in Figure 4 of the drawing wherein one or both faces of the board I are provided with a plurality of spaced parallel discontinuous or spaced series of aligned slits 5a, the slits 5a in each aligned series in one face of the board being staggered with respect to the slits la of the adjacent series as shown in solid line in said Figure 4, and, where both sides of the board are slitted, also with respect to the slits 5a 4;. of the corresponding series thereof provided in the opposite face of said board and represented by dotted lines, Figure 4.

The present invention affords or provides a plaster baseboard which embodies all of the ad- o5 vantages of such board and at the same time eliminates the objectionable longitudinal cracking of plaster heretofore quite prevalent and resulting from the expansion and contraction of the board.

While a particular embodiment of the invention has been illustrated and described, it is not intended that the invention be limited to such disclosure but that changes and modifications may be made and incorporated therein within the scope of the annexed claims.

I claim: 1. A plaster baseboard consisting of a relatively rigid body of fibrous material having oppositely facing plane surfaces each provided with a plurality of spaced parallel slits therein of a depth at least one-half the thickness of said board body, the slits in each plane surface being alternately staggered with respect to the slits in the opposite plane surface arid providing gaps in the board body sufficient to absorb expansion in said body and prevent distortion of the board beyond the normal plane and boundaries thereof, said slis having a width sufficiently narrow that plaster applied to said surfaces of the board will not fill the slits and thereby prevent the absorption of expansion and distortion by the gaps provided by said slits.

2. A plaster baseboard consisting of a relatively rigid body of fibrous material having oppositely facing plane surfaces each having therein a plurality of spaced parallel groups of relatively narrow slits arranged in spaced alignment and of a depth at least one-half the thickness of said board body, the slits in each aligned group being alternately staggered with respect to the slits in an adjacent group in the same plane surface of the board and the slits in the corresponding aligned group in the opposite plane surface thereof to provide gaps in the board body sufficient to absorb expansion in said body and prevent distortion of the board beyond the normal plane and boundaries thereof, said slits having a width sufficiently narrow that plaster applied to said surfaces of the board will not fill the slits and thereby prevent the absorption of expansion and distortion by the gaps provided by said slits.

HENRY W. PIQUET.