Board element

Claim 1

A lightweight board element comprising a lightweight core having a plurality of cellular cavities and a covering layer provided on the upper and lower surfaces of the core, said layer comprising synthetic resin and resin-impregnated glass fiber mat coextensive with the core, and further comprising wire fabric embedded in said synthetic resin covering layer for receiving fastening screws, said core comprising a rigid plastic foam board-like element having a first grid pattern of intersecting grooves on its upper surface and a second grid pattern of intersecting grooves on its lower surface, the first and second grid patterns being formed in the respective upper and lower surfaces of the core and being separated from one another, each of said first and second grid patterns being formed by a series of longitudinal and transverse grooves extending across the respective upper and lower surface of the core, each of said grooves having a width of about 1 to 3 mm, a depth of about 3-6 mm, and being separated by a distance of about 0.5 to 1.5 cm, said longitudinal and transverse grooves intersecting and forming said grid patterns.

Claim 10

A method of making a lightweight board element comprising the steps of providing a first mold half having a peripheral side wall and a bottom wall; providing a second mold half engageable with said first mold half to form a board-shaped mold cavity; providing first layers of curable synthetic resin adjacent the mold surfaces of said first and second mold halves, such that the resin covers the mold surfaces including said peripheral side wall; curing said first layer of synthetic resin; providing a layer of glass fiber adjacent the cured first layer of resin such that the layer of glass fiber covers the cured resin layer including the resin layer on said peripheral side wall; coating a second layer of curable synthetic resin on said layer of glass fiber such that the resin penetrates into and saturates the glass fiber; locating a lightweight rigid plastic foam core between the mold halves; pressing the mold halves together to contact the core and the glass fiber layers saturated with said second layer of curable synthetic resin; and curing said second layer of curable synthetic resin to bond said core thereto to form a unitary board element, said core having a grid pattern on its upper and lower surfaces, said grid pattern being formed by a series of longitudinal and transverse grooves extending across the upper and lower surfaces of the core, said grooves intersecting and forming said grid pattern.

Claim 11

A method of making a lightweight board element comprising the steps of providing a first mold half having a peripheral side wall and a bottom wall; providing a second mold half engageable with said first mold half to form a board-shaped mold cavity; providing first layers of curable synthetic resin adjacent the mold surfaces of said first and second mold halves, such that the resin covers the mold surfaces including said peripheral side wall; curing said first layer of synthetic resin; providing a layer of glass fiber adjacent the cured first layer of resin such that the layer of glass fiber covers the cured resin layer including the resin layer on said peripheral side wall; coating a second layer of curable synthetic resin on said layer of glass fiber such that the resin penetrates into and saturates the glass fiber; locating a lightweight rigid plastic foam core between the mold halves; pressing the mold halves together to contact the core and the glass fiber layers saturated with said second layer of curable synthetic resin; and curing said second layer of curable synthetic resin to bond said core thereto to form a unitary board element, said core having a grid pattern on its upper and lower surfaces, said grid pattern being formed by a series of longitudinal and transverse grooves extending across the upper and lower surfaces of the core, said grooves intersecting and forming said grid pattern.