1. Interior Wall and Ceiling Finish
Unit 58
Interior Wall and Ceiling Finish
Gypsum Board Wallcovering • Wall Paneling • Plastic Laminate Wall Covering • Ceiling

2. Gypsum board is fastened directly to wood or metal framing members and provides a smooth surface for paint or wallcoverings.
Gypsum board, also known as drywall or wallboard, is commonly used for interior wallcovering. Most new houses are constructed with gypsum board wall finish. Gypsum board can be fastened to wood, metal, concrete, or masonry. See Figure 58-1.

3. Gypsum boards have different edge shapes depending on their purpose.
Gypsum boards have differently shaped edges along their longer side, depending on their purpose. See Figure 58‑2. Gypsum board designed to receive a painted finish usually has a tapered edge to provide a recessed joint between the long edges of the boards. The recessed joint receives the paper tape and joint compound that is used to cover the joints between the boards. Predecorated gypsum board has rounded or beveled edges. Boards to be covered with other materials, such as plastic laminate or wood paneling, have tongue‑and‑groove edges.

4. Gypsum board is cut by scoring it on the face side and then snapping off the waste piece.
After a gypsum board panel is measured and marked, it is usually cut by scoring the face with a sharp knife, then snapping off the waste piece. See Figure 58‑3.

5. Jagged gypsum board edges can be smoothed with a serrated-blade forming tool.
Jagged edges should be smoothed with a rasp, knife, or serrated-blade forming tool. See Figure Sometimes cuts can be made more conveniently with a saw.

6. In single-ply application, only one layer of gypsum board is used.
The single‑ply system of application is most often used for gypsum board in residential and other light construction applications. See Figure 58‑5. A single layer is adequate for fire resistance and sound control. The boards are applied with the long edge in a vertical or horizontal position.

7. In double-ply application, an adhesive is used to bond the second layer of gypsum board to the base layer. The second layer runs at a right angle to the base layer.
The double‑ply system provides greater fire resistance and sound control than the single‑ply system. The first layer of wall­board is fastened to the studs. The second layer is then applied with an adhesive and tacked in place. See Figure 58‑6.

8. A metal foot lift is used to raise a gypsum board wall panel up tightly against the ceiling. The space below the panel is covered by base molding.
Panels are applied to the ceiling first and then to the walls. Wall panels should butt tightly against the ceiling panels. A foot lift can be used to raise the wall panels up against the ceiling panels to ensure a tight fit. See Figure 58‑7.

9. Nails may be used to fasten gypsum board to wood framing members
Nails may be used to fasten gypsum board to wood framing members. Small-headed nails are used with predecorated panels.
Nails used to fasten gypsum board to wood framing members must be long enough to go through the gypsum board and penetrate 3/4″ to 7/8″ into the wood. The heads should be at least 1/4″ in diameter, flat or concave, and thin at the rim. See Figure 58‑8.

10. Nails must be driven properly to ensure a solid connection between the gypsum board and wood framing member. Nails driven too deeply, or at an angle, will cut through the face covering.
Gypsum board should be pressed tightly against wood framing members while nails are driven in. The nail should be driven in far enough to produce a dimple on the surface of the board, but not far enough for the head to cut into the face covering. See Figure 58‑9. The dimple is later filled with joint compound, hiding the head of the nail.

11. Loose nails are caused by a poor fit of the gypsum board to the framing surface or by nails missing the framing members.
Improperly driven nails can result in loose gypsum board. As a result, cracks may later appear in the finished wall. Nails that do not catch the wood properly can work loose and eventually pop out. See Figure 58‑10.

12. The proper single-nailing pattern ensures a sound connection between the gypsum board and wood framing member. Nailing should begin at the center of the panel and move outward.
The single‑nailing method, shown in Figure 58‑11, or double‑nailing method, as shown in Figure 58‑12, may be used to fasten gypsum board to framing members. With both methods, first drive the nails in the center of the board and move outward toward the edges to prevent a sag or bulge at the center of the gypsum board panel. The same nailing patterns are used for walls and ceilings, with the edges of ceiling panels fastened 7″ OC.

13. When double-nailing gypsum board, the second set of nails may be driven after the first set is driven across the entire panel, or the second set of nails in each row may be driven after the first set in each row is driven. Nailing should begin at the center of the panel and move outward.
The single‑nailing method, shown in Figure 58‑11, or double‑nailing method, as shown in Figure 58‑12, may be used to fasten gypsum board to framing members. With both methods, first drive the nails in the center of the board and move outward toward the edges to prevent a sag or bulge at the center of the gypsum board panel. The same nailing patterns are used for walls and ceilings, with the edges of ceiling panels fastened 7″ OC.

14. Screws may be used to fasten gypsum board to metal or wood framing members. A drywall screwdriver is used to drive the screws.
The heads of most drywall screws are bugle-shaped. Bugle-shaped heads are designed to catch the gypsum board face paper and pull it in rather than tear it. Bugle heads displace less material than other head shapes and create less gypsum dust. Drywall screws are applied with a drywall screwdriver. See Figure

15. Stud adhesive is used with screws or nails to fasten single-ply gypsum board to wood or metal framing members.
Tube-dispensed stud adhesive is used with screws or nails to fasten single‑ply gypsum board to wood or metal framing members. A 1/4″ to 3/8″ bead is applied to each stud. See Figure 58‑14.

16. Gypsum board must be properly finished to ensure a smooth and even surface.
After all ceiling and wall panels are nailed in place, joints between panels are finished by painters or other tradesworkers called tapers who specialize in finishing gypsum board. See Figure Gypsum board joints are filled with a joint compound and a strip of reinforcing tape is pressed into the compound. Two additional layers of joint compound, forming a topping coat, are applied. Each layer of joint compound must dry completely and may require light sanding before the next layer is applied. The final coat, called the finish coat, of joint compound is applied and feathered out on each side of the joint. Nail or screw dimples are also filled with joint compound and lightly sanded.

17. Metal corner beads reinforce outside corners of gypsum board.
Joint compound is also applied to the inside corners. Reinforcing tape is folded and pressed into the compound. Metal corner beads, which reinforce outside corners, are installed and covered with joint compound. See Figure When all joints, corners, and nail dimples have been treated and sanded, the wall is ready for painting.

18. Molding is used to cover joints and corners of predecorated gypsum board.
Predecorated gypsum board panels are usually applied with the long edge in a vertical position. The joints may be exposed or covered with the types of molding shown in Figure

19. Grooved softwood-veneer plywood wall panels create pleasant shadow lines.
Most plywood wall panels have a hardwood veneer such as oak, ash, beech, walnut, birch, pecan, or mahogany. However, softwood‑veneer panels such as redwood, cedar, fir, and southern pine are also available. The surface may be plain or textured. See Figure 58‑18. Plywood panels are usually 1/4″ or 3/8″ thick. Thicker panels, such as 3/4″, are also available. Standard sheet sizes are 4′ × 8′ and 4′ × 10′. Longer lengths are available by special order.

20. Wall paneling may have rabbeted or beveled edges, forming channel or V-joints respectively.
Panels may have a rabbeted or slightly beveled edge. When panels are placed together, rabbeted edges form a channel joint; beveled edges form a V-joint. See Figure 58‑19. Both types of joints create an attractive shadow line between the panels.

21. Plywood panels are stacked with wood strips between them for preconditioning to room temperature.
Plywood panels should be preconditioned to room temperature for several days before they are applied to a wall. A good procedure is to stack the panels with strips between them. See Figure 58‑20. This allows air to reach the faces and backs of the sheets, conditioning them to room temperature and humidity. Preconditioning eliminates significant shrinkage after the panels have been nailed in place.

22. Furring strips are installed over existing uneven walls to provide a smooth and even wall surface for plywood or hardboard panels.
In remodeling work, panels are often placed directly over the plastered or gypsum board surface of the existing walls. Frequently, these surfaces are very uneven, and furring strips should be used. A procedure for installing furring strips is shown in Figure 58‑21. Shims tapered from 1/2″ thick to about 1/8″ thick are used to plumb and straighten the furring strips where necessary.

23. Panels can be positioned so that a continuous joint occurs on each side of the door or so joints break over the openings.
Before installing panels, determine their arrangement on the walls. Figure 58‑22 shows two possible ways for placing panels on the same wall. Whatever arrangement is used, panels should be set up around the walls so that panels with better matching grain patterns are next to each other. When the final panel arrangement has been determined, number the backs of the panels so they can later be installed in that order.

24. Holes for electrical outlets and other openings must be laid out before the panel is set in place. The openings may be cut before or after the panel is positioned using a cutout saw.
Holes for electrical outlets, switches, or other openings must be laid out on the panel before the panel is set in place. See Figure 58‑23 for the layout procedure. The openings may be cut before the panel is set in place using a keyhole saw or jigsaw, or they can be cut in the panel when the panel is in place using a cutout saw.

25. The item requiring an opening—in this case an electrical box—is used as a pattern for marking a panel opening.
When cutting the opening before the panel is set in place, the item requiring an opening is used as a pattern for marking the opening. See Figure The outline is made slightly larger than the item. Starter holes are drilled in the inside corners of the outline. A jigsaw or cutout saw is used to cut along the marked lines. If a jigsaw is not available, a keyhole saw can be used, although it is not as efficient.

26. When installing wall panels over stud walls, the edges of the panels must fall over the centers of the studs.
A typical method for applying wall panels is shown in Figure 58‑25.

27. Base and ceiling moldings eliminate the need to scribe the top and bottom panel.
When the top and bottom of a panel are covered by moldings, the top and bottom edges do not need to be scribed. See Figure 58‑26. In contemporary construction, ceiling molding is usually not installed, so the top of the panel must be scribed to the ceiling.

28. Molding is often used to cover the inside and outside corners of interior paneling.
Inside and outside corners do not have to be fitted carefully if they are to be covered by moldings. See Figure 58‑27.

29. A panel must be carefully scribed to the other wall when no molding covers the inside corner.
If no molding is used on an inside corner, a scriber must be used as shown in Figure 58‑28.

30. Wall panels may be mitered if molding is not used on an outside corner.
If molding is not used on an outside corner, the corner may be mitered. See Figure 58‑29.

31. Flush application of panels on outside corners is easier than mitering and panel edges are less susceptible to damage.
However, these corners are difficult to miter properly and can be easily damaged after mitering. A better method of finishing corners is to fit a corner strip flush with the panel as shown in Figure 58‑30.

32. Nails are less noticeable when driven along the bevel or into the grooves of a panel.
Nails or adhesives may be used to fasten wall paneling. Finish nails for paneling should be long enough to penetrate 3/4″ into the studs or furring strips. When using grooved panels, drive nails into the grooves located in the body and along the edge of each panel. If panel edges are chamfered, place the nail along the chamfer. See Figure 58‑31. All nails except those that are colored to match the paneling must be set below the surface with a nail set. The nail heads are later concealed with wood putty that matches the finish of the panel.

33. Adhesive is applied in 3″ long beads, 6″ apart, at intermediate studs or at furring strips behind the panel.
Most paneling, especially hard­board paneling, is fastened with adhesive rather than nails. A few nails may be required to hold the panels in place until the adhesive sets. Adhesive is applied for the sides and top and bottom edges of the panel in a 1/8″ continuous strip behind the panel joints and at the top and bottom plates. Adhesive is applied in 3″ long beads, 6″ apart at the intermediate studs or furring strips behind the panel. See Figure 58‑32.

34. A wall panel is pressed into place after the adhesive has been applied.
The panel is pressed into place with firm, uniform pressure so the adhesive spreads evenly and the panel is tacked at the top. See Figure 58‑33.

35. After the panel has been pressed against the adhesive, it is grasped at the bottom along both edges and slowly pulled away from the stud. The panel is then pressed back into position after 2 min.
The panel is then grasped at the bottom along both edges and slowly pulled away from the stud. See Figure 58‑34. After two minutes, the panel is pressed back into position.

36. Solid board paneling may be applied horizontally.
Solid board paneling consists of solid wood boards, usually 3/4″ thick and 4″ to 12″ wide. Softwood species such as redwood, fir, pine, hemlock, spruce, and cedar are used. Finishes are smooth, textured, or rough (resawn). Solid board paneling is generally placed horizontally or vertically, although diagonal designs are sometimes used. See Figure Four common types of solid board panels include the following:
• board‑on‑board
• board‑and‑batten
• tongue‑and‑groove
• channel‑rustic

37. When installing board-on-board wall paneling, drive an 8d nail at the center of the underboard. The top boards should overlap the underboard a minimum of 1″. Fasten the top board with two 10d nails. Make sure the nails clear the underboard to allow for expansion and contraction.
In the board‑on‑board system, one 8d nail is driven at the center of each underboard. See Figure 58‑36. Top boards should overlap underboards a minimum of 1″. The top board is fastened with two 10d nails, one in each edge. Ensure the top board nails clear the underboard to allow for expansion and contraction.

38. When installing board-and-batten wall paneling, drive an 8d nail at the center of the underboard. The underboards are spaced approximately 1/2″ apart. Drive a 10d nail through the center of the batten.
In the board‑and‑batten system, one 8d nail is driven at the center of each underboard. See Figure 58‑37. The underboards are spaced approximately 1/2″ apart. One 10d nail is driven at the center of the batten.

39. When installing tongue-and-groove wall paneling, 4″ and 6″ widths can be blind-nailed with 6d finish nails driven at a 45° angle. This method eliminates the need to countersink and putty face nails.
In the tongue‑and‑groove system, boards 4″ to 6″ wide are blind‑nailed with 6d finish nails driven at a 45° angle. See Figure 58‑38. Blind-nailing eliminates the need to countersink and putty the face nails.

40. When installing channel-rustic solid board paneling up to 6″ wide, one face nail is adequate to secure the board. Widths over 8″ require a face nail at the center of each board.
In the channel‑rustic system, boards up to 6″ require only one face nail. Boards 8″ or wider also require a face nail at the center of each board. See Figure 58‑39.

41. Blocking must be placed in a stud wall to provide a nailing base for vertical board paneling.
When boards are fastened vertically to a stud wall, blocking must be placed between the studs. See Figure 58‑40. Masonry walls require horizontal furring strips.

42. Prior to installation, solid board paneling is arranged along the wall so wood grain and other features can be matched to each other.
Before solid board paneling is installed, the boards should first be arranged along the wall so the grain and other features can be matched as closely as possible. See Figure 58‑41. Cut openings for electrical outlets and vents in the boards before they are placed.

43. When tapping a board panel into place, use a piece of material with a grooved edge against the board to avoid damaging the edge.
The inside corner board is placed first, in plumb position, and scribed if necessary to match the profile of the adjoining wall. The corner board is fastened securely before the next board is placed. If boards are to be glued, the adhesive is applied to the backs of the prefitted boards. Press the board against the wall so the adhesive spreads evenly. Remove the board, wait a few minutes, then push the board back into place. When tapping a board panel into place, use a piece of material with a grooved edge against the board. See Figure 58‑42. The grooved edge will protect the board from damage. Face nail the board at the top and bottom with 8d finish nails.

44. Plastic laminate wall panels are available with an imitation wood grain finish.
Plastic laminate is very hard and smooth, and is composed of three or four layers of plastic material bonded under high heat and pressure. Many different patterns are available, including imitation wood grain. See Figure 58‑43.

45. Suspended tile ceiling systems are frequently used in commercial construction.
Acoustical and decorative ceiling tiles are another method for finishing ceilings. Ceiling tiles are especially practical in remodeling work since the tiles can be directly applied to existing plaster or gypsum board ceilings. Ceiling tile may also be used to form a suspended ceiling. In commercial construction, suspended tile ceiling systems are frequently used. See Figure 58‑44.

46. Ceiling tile with tongue-and-groove edges are stapled through the wide flanges into the furring strips.
For direct application to furring strips or to an existing plaster or gypsum board ceiling in an average-size room, 12″ × 12″ tiles, 1/2″ or 3/4″ thick, with tongue‑and‑groove edges, are usually the most practical. See Figure 58‑45.

47. For a ceiling with even-foot dimensions, the center tiles are positioned at each side of the centerlines.
For ceilings with even-foot dimensions, such as 8′ × 10′ or 10′ × 12′, and using 12″ × 12″ tiles, the center tiles are placed on each side of the centerlines. This placement results in full 12″ border tiles. See Figure

48. For a ceiling with odd-foot dimensions, the center tiles are positioned so the centerlines align with the middle of the tiles.
For ceilings with odd-foot dimensions, such as 9′ × 13′, and using 12″ × 12″ tiles, the tiles are centered over the centerlines in order to produce full 12″ wide border tiles. See Figure

49. Border tiles on opposite sides of the ceiling should be the same width, and should be at least 6″ wide.
Room dimensions are often in feet and inches; therefore, border tiles will not be a full 12″. Border tiles on opposite sides of the ceiling should be the same width, and should be at least 6″ wide. To ensure that the border tiles are the same width and at least 6″ wide, add the width of one tile (12″) to the inch portion of the ceiling length or width dimension and divide by 2. The answer is the proper width for the opposite border tiles. See Figure

50. Suspended ceilings are often installed in commercial buildings.
For a suspended ceiling, a light metal grid is hung by wire from the original ceiling or from ceiling joists. Tiles (typically 2′ × 2′ or 2′ × 4′) are then placed in the frames of the metal grid. See Figure Suspended ceilings are often used in commercial construction and in residential structures with high original ceilings.

51. Recessed lighting can be used with suspended ceilings
Recessed lighting can be used with suspended ceilings. Plumbing, lighting, and ventilation fixtures must be properly secured to structural members above a suspended ceiling.
One advantage of a suspended ceiling is that it reduces the sound traveling from the floor above and increases the insulating capability of the ceiling. Suspended ceilings also allow the use of recessed lighting. See Figure Pipes, wires, and ductwork can be conveniently run above the suspended ceiling.

52. A laser level is commonly used to establish the suspended ceiling height at several locations along the wall.
The first step in installing a suspended ceiling is to snap lines on the wall to establish the correct height for the ceiling. A laser level is commonly used to establish the ceiling height around the entire room. See Figure

53. A suspended ceiling framework consists of main runners and cross tees, which are supported by hanger wires. Ceiling tile panels are supported by the runners and cross tees.
Wall angles are fastened to the wall. Main runners of the metal grid are suspended from the ceiling or other structural elements with hanger wires. See Figure 58‑52. Cross tees are placed between the main runners and secured in position using tabs at the ends of the cross tees, which engage in slots of the runners. Finally, ceiling tiles are placed in the grid flanges.