MDF is a manufactured wood product consisting of wood fibres compressed to create strong panels that you can work with like natural wood. Homeowners often use these panels in place of plywood or particleboard when finishing bare masonry walls, or as a flat, smooth base for wood veneer or plastic laminate on walls of all types. The procedure for mounting MDF follows those same procedures used with mounting other wood panel products. You either attach the panels to the studs comprising your home's framework, or create a framework consisting of wood furring strips when the studs aren't available.
Lay the panels in the room where you're mounting them at least 48 hours prior to installation to acclimatise them to the room's temperature and humidity levels. Lean the panels against the walls of the room, tilted so that as much of the surface of the boards as possible are exposed.
Check for any high spots on the wall if mounting directly to drywall or plaster. Use a belt sander to sand the high spots down to create an even surface for mounting. Wipe away any sanding residue using a clean cloth. Use a stud finder to locate the wall studs behind the walls that you wish to mount the MDF. Mark the stud locations by snapping a vertical chalk line against the wall following the stud centres.
Prepare masonry walls for MDF mounting by attaching a series of wooden 1x2-inch furring strips vertically along the wall spaced 16 inches apart for mounting the boards. Connect the vertical furring in between horizontal 2x4-inch boards running along the top and bottom of the walls as support for the vertical strips. Attach the framework of furring strips to the wall using either construction adhesive or masonry screws.
Cut foam board insulation panels to fit the spaces between the furring strips with a utility knife and glue in place with construction adhesive. Cover the boards and strips with a layer of 4 mil vapour retarder glued into place with the adhesive, and then nail water-resistant gypsum wall board to the strips. Cut the wall boards as needed by scoring the boards with the utility knife and then snapping them along the scored line. Cover the entire mounting area with the wall board as a base for attaching the MDF.
Stand the MDF panels against the wall where you wish to place each one. Maintain a gap of 1/16 inch between each board for expansion. Increase the gap to 3/16 inch when bordering an MDF panel against a door or window. Measure the height of the walls and cut the panels to fit, leaving 1/4 inch of clearance on both the top and bottom of the boards for expansion. Cut the panels face up using a table saw.
Mount the boards to the walls beginning in a corner of the room, leaving a 1/16 inch gap between the edge of the board and the corner. Set the panel so that the left and right edges of the MDF falls onto a stud or furring strip. Apply a latex water-based adhesive to the rear of the board using a caulking gun in a continuous strip along the perimeter of the board and along any intermediate stud or furring strip lines on the wall.
Press the board to the wall and hold it in place for 30 seconds. Release the board and then tap along the perimeter of the board using a hammer against a padded wood block placed against the board to ensure the adhesive binds the MDF to the wall at all points.