W.F. Mason, who founded the Masonite Corporation, first produced hard density fiberboard (HDF) in 1924. For this reason, HDF is popularly known as Masonite. You can use it for many interior applications, including paneling, flooring underlayment, cabinetry and doors. You can also use HDF for exterior siding, after it has been tempered and heat-treated with special oil to make it water-resistant. You can cut, nail and screw HDF as easily as plywood, and its smooth surface takes paint and other finishes well. It provides a superior substrate for gluing vinyl and linoleum flooring.
Lay hardboard on a plywood subfloor to provide a smooth underlayment for vinyl, linoleum or tile. Before you lay it, scrub the rough side of each board with water. Lay the boards out, rough side to rough side, and leave them overnight.
Lay the boards on the subfloor with the smooth side facing up and nail them with ring shank nails. As the boards dry out, they will contract and form a hard, smooth surface with no bubbles.
Use tempered hardboard for siding. This comes with the exterior side prepainted. For best results, paint the other side with primer before you install it, giving an extra coat to the bottom edge and the first few feet from the bottom. This will seal the hardboard against moisture and add years to its life.
Nail hardboard siding to the studs with ring shank nails, and pound the heads flush without countersinking them. If the heads of the nails sink in, they will break the fiber surface and allow moisture seepage.
Allow for small gaps between hardboard siding panels. This will allow the walls to breathe and moisture to escape.
Cut hardboard with power saws in the same way you would cut plywood. The surface of hardboard doesn't chip as easily as plywood, so you can use a utility blade on your circular saw and a regular wood-cutting blade on your jigsaw or reciprocating saw.