Hardboard panel siding

Disclosed is an exterior grade hardboard siding panel which gives the appearance of vertically-applied solid lumber planks having a bead and cove detail. The front surface of the panel has a plurality of adjacent areas which each simulate a vertical solid wood plank. Each of these areas has a cove recess at one edge and a bead adjacent to a cove at the opposite edge. The areas are arranged with the cove of one area and the cove adjacent to the bead of an adjacent area, both facing the bead. The coves are separated from the bead by narrow grooves which provide good breaking points in the design and added damage resistance at the edges of the panels which are joined with shiplap joints.

BACKGROUND OF THE INVENTION 
The present invention relates to exterior siding, and more particularly to 
hardboard siding configured to give the appearance of vertical solid wood 
planks with decorative edge details. 
The art has recognized that it is possible to achieve considerable savings 
in both labor and materials by employing hardboard siding panels in place 
of conventional solid wood planks. Prior art panels of this type have been 
produced with a variety of surface effects, including horizontal lap 
siding, vertical board and batten siding, and simulated cedar shake 
siding. Among the variations of horizontal lap siding which have been 
available are various lap sidings including straight edge and colonial 
edge beaded lap siding. There are currently a wide variety of panels 
available with both smooth and textured facings. 
Because one of the main advantages of hardboard panel siding is its 
substantial surface area in a relatively thin sheet, damage to the edges 
of the panels has heretofore been a problem. It has been possible to 
control damage by effective packaging, a critical requirement for panels 
with edges configured to form shiplap joints. There is a difficulty, 
however, in providing good resistance to edge damage in panels having 
anything but the simplest shiplap edge configurations. Thus, where 
detailed surface designs, especially those of a vertical nature such as 
the simulation of solid wood planks having an edge detail, are desired it 
is difficult to provide a realistic simulation of the intended design and 
at the same time provide adequate damage resistance at the edges. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide exterior grade 
hardboard siding panels which provide the appearance of a multiplicity of 
vertically-applied solid lumber planks having a bead and cove detail and 
which are mateable to form a surface, wherein the mating area between the 
panels is virtually indistinguishable from the individual areas on the 
panel which define the planks. 
Another object of the present invention is to provide an exterior grade of 
hardboard siding panel which provides the appearance of a multiplicity of 
vertically-applied lumber planks having a bead and cove detail wherein the 
design is modified slightly at the shiplap edge to provide added 
resistance to damage during transport and handling. 
These and other objects are accomplished according to the present invention 
which provides an exterior grade hardboard siding panel for application to 
vertical surfaces to protect the surfaces from the weather and to provide 
the appearance of a multiplicity of vertically-applied solid lumber planks 
having a bead and cove detail, comprising a thin rectangular panel having: 
(a) a front surface configured with a plurality of adjacent areas each 
simulating a vertical solid wood plank, wherein each area has a shallow 
cove recess at one edge and a like cove recess adjacent to a bead at the 
opposite edge, and said plurality of areas are arranged such that (i) the 
cove recess of one edge of one area and the cove recess adjacent to the 
bead of the next adjacent area have their recessed surfaces facing said 
bead of said next adjacent area, (ii) both said coves are separated from 
said bead by narrow grooves, and (iii) said bead extends upwardly from the 
base of said grooves to a crest which is approximately tangential to the 
outermost plane of the front surface; (b) a substantially planar back 
surface; (c) a first edge of reduced thickness forming the bottom lap of a 
shiplap joint, the back surface of which is a continuation of said 
substantially planar back surface, and the front surface of which is 
recessed to a level below the base of a groove which terminates the front 
surface configuration directly adjacent to the recessed area; and (d) a 
second edge of reduced thickness opposite said first edge, forming the top 
lap of shiplap joint, the back surface of which is recessed from said 
substantially planar back surface, and the front surface of which is a 
substantially continuation of the front surface configuration and 
terminates with a recessed cove.

DETAILED DESCRIPTION OF THE INVENTION 
The panels provided according to the present invention are exterior grade 
hardboard siding panels which have as their primary utility the 
application to vertical surfaces on the exterior of building structures to 
protect the surfaces from the weather. While this is the primary purpose 
of panels of this type, it is well recognized that they can also be 
employed on horizontal surfaces, especially for soffit applications, as 
well as purely decorative applications where protection from weathering is 
not essential. These panels may also be employed as substitutes for 
interior paneling. The panels comprise thin rectangular sheets which are 
typically four feet in width and from 7 to 16 feet in length. However, the 
present invention is not restricted to these particular outside 
dimensions. It is considered important, however, that the panels be 
relatively thin. Typically, exterior siding panels of this type will have 
thicknesses ranging from about 3/8 of an inch to 1/2 of an inch. It is 
within the contemplation of the present invention to form panels of 
thicknesses ranging from 1/4 inch to about 3/4 of an inch. 
A panel is shown generally as 10 in FIG. 1 to have a plurality of areas 12 
which provide the appearance of a multiplicity of vertically-applied solid 
lumber planks having a bead and cove detail. The panel 10 is shown in the 
figures as having a saw-textured, wood grain surface; however, it is 
within the contemplation of the invention to provide smooth surface 
panels. The critical feature of the present invention is not the 
particular texture of the plank area surfaces, but the provision of a 
panel having a realistic appearing simulation of solid wood planks having 
cove and bead detail which are suitably resistant to normal damaging 
stresses encountered in handling and shipment. 
The front surface 12 of the panel 10 is configured with a plurality of 
adjacent areas 14 each of which simulates a vertical solid wood plank. On 
each area 14 there is a shallow cove recess 16 at one edge and a like cove 
recess 18 adjacent to a bead 20 at the opposite edge. As shown in FIG. 1, 
a plurality of these areas 14 are arranged such that the cove recess 16 of 
one edge of one area and the cove recess 18 adjacent the bead 20 of the 
next adjacent area 14 have their recessed surfaces facing the bead 20 of 
the next adjacent area 14. As shown, both of the coves 16 and 18 are 
separated from the bead 20 by narrow grooves 22. Each bead 20 extends 
upwardly from the base of grooves 22 on either side of the bead 20 such 
that its upper surface or crest is approximately tangential to the 
outermost plane of the front surface 12 of the panel 10. 
The back surface 24 of the panel 10 is substantially planar. By this it is 
meant that there is no requirement for any particular rear surface detail 
according to the invention. It is intended, however, that the rear surface 
24 can have whatever detail is conventional for non-facing hardboard panel 
surfaces. Thus, it is well recognized in the art that the rear surface of 
a hardboard panel can be randomly or non-randomly roughened to permit 
better adhesion with adhesives employed to fasten, position or seal the 
panel to a substrate. 
The panel has a first edge 26 of reduced thickness for forming the bottom 
lap 28 of a shiplap joint shown in cross section in FIG. 3. The back 
surface of the edge of reduced thickness 26 is a substantial continuation 
of the planar back surface 24. The front surface of the edge of reduced 
thickness 26 is recessed to a level below the base of a groove 22 which 
terminates the front surface configuration directly adjacent to the 
recessed area at the edge portion 26. 
Similarly, a second edge of reduced thickness 32 is formed on the edge of 
the panel opposite the first edge 26. This second edge forms the top lap 
34 of a shiplap joint as shown as 30 in FIG. 3. The back surface of the 
second edge 32 is recessed from the substantially planar back surface 24. 
The front surface of the second edge 32 is a substantial continuation of 
the front surface configuration and terminates with a recessed cove 16. 
According to a preferred embodiment of the present invention, the detail of 
the first edge 26 and the second edge 32 and the associated cove and 
groove detail directly adjacent thereto are slightly differently 
dimensioned to make these vulnerable edges of the panels as thick as 
possible to minimize damage in shipping and handling. These differences in 
dimensional detail provide a desirable balance between the provision of 
maximum edge strength in a panel of this type and the overall appearance 
of the panel. Thus, according to this preferred embodiment, the cove 16 
which terminates the front surface of the second edge 32 has a radius of 
curvature less than the coves 16 and 18 formed on the remainder of the 
panel. However, the linear extent of the cove 16 across the width of the 
panel 10 is substantially the same as for the coves 16 and 18 formed on 
the remainder of the panel 10, whereby the strength of the second edge 32 
is improved while not adversely affecting the appearance of the bead and 
cove detail. 
According to one preferred embodiment of the invention a panel is formed 
483/4 inches in width with a series of 6 plank defining areas 14 each 
being approximately 8 inches in width. This configuration leaves 3/4 of an 
inch for a first edge portion 26 for the shiplap joint. The second edge 32 
opposite the first edge 26 has a recess extending 3/4 of an inch across 
the back width of the panel. The panel itself has a 7/16 inch nominal 
thickness. The grooves 22 are formed to a depth of 3/16 of an inch, are 
1/16 inch wide and border a 9/16 inch diameter bead 20 the upper surface 
of which is approximately tangential to the outermost plane of the front 
surface of the panel. The coves 16 and 18 are 3/4 inch radius recesses 
which extend 1/8 of an inch in depth into the panel and 3/8 of an inch 
across the width of the panel. The cove recess 16 at the second edge 32 of 
the panel has a radius of curvature less than the radius of curvature of 
the other cove recesses. By this arrangement, the cove recess at the end 
of the second edge 32 still extends 3/8 of an inch along the width of the 
front surface 12 of the panel, however the depth of recess is less than 
the depth of the other cove recesses. The thickest area of the second edge 
32 is 7/32 of an inch while the thinnest area at the extreme edge of the 
panel is 3/32 of an inch. Thus, in accordance with the subject invention, 
th shallower curve utilized to define the cove recess at the second edge 
32 of the panel results in less material being removed from the panel 
leaving a thicker, less vulnerable edge area, which will not substantially 
change the appearance of the board. The first edge thickness is 1/8 of an 
inch. A panel of these desirable dimensions provides a realistic 
simulation of solid wood planks having a bead and cove detail, in 
combination with suitable strength for standing up to shipping and 
handling. 
The hardboard panels of the present invention can be made according to 
conventional technology and are not limited in this regard; however, it is 
preferred for the best balance of strength, surface detail and integrity, 
and economy, to provide panels having a density of about 31 pounds per 
cubic foot or greater. Preferably, these panels are prepared from 
ligno-cellulosic fiber and will typically have a resinous binder such as 
phenol formaldehyde incorporated therein. The panels are typically formed 
by pressing under elevated temperature and pressure. 
The above description is for the purpose of describing the invention to the 
person of ordinary skill in the art and it is not intended to detail all 
those obvious modifications and variations of it which will become 
apparent upon a reading. It is intended, however, that all such obvious 
modifications and variations be included within the scope of the present 
invention which is defined by the following claims.