Unit 43

1. Unit 43 Wall Framing Wood-framed Wall Components • Constructing Wood-framed Walls • Sheathing Exterior Walls • Weather Barriers • Rainscreen Walls • Structural Insulated Panels (SIPs) • Shear Walls

2. Wood-framed wall components include studs, plates, headers, trimmer studs, sills, cripple studs, and corner posts. Exterior walls are commonly covered with structural panels such as oriented strand board or plywood.

3. Corner posts are constructed wherever a wall ties into another wall. Straight studs are used to frame corner posts. When an inside corner is constructed using a block laid flat, a carpenter must insulate the U-shaped cavity before exterior wall sheathing is applied. When metal clips are used, the wall cavity can be insulated after exterior wall sheathing is applied

4. Rough door and window openings must allow for the finish frame and a required clearance around the frame.

5. Various methods are used to construct door and window headers.

6. Header size is determined by the width of the opening and load bearing down from above. For example, a 4 × 6 Douglas fir header can be used for an opening up to 6′‑0″ wide.

7. A 12″ wide solid header can be used to accommodate a 6′-8″ door in an 8′-1″ standard-height wall.

8. When a header less than 12″ wide is installed, cripple studs are installed between the top of the header and top plate.

9. Corner braces may need to be installed in rough openings for installation of oval or round windows.

10. T-shaped metal braces fit into saw kerfs in the studs.

11. Fireblocking is required in concealed spaces to cut off vertical and horizontal draft openings and to form a barrier between stories.

12. Fireblocking caulk is applied to joints or openings in walls or structural members to inhibit the spread of fire, smoke, and fumes.

13. Wood-framed walls may be assembled while they are lying on the subfloor.

14. Lines are snapped to indicate the exact locations of walls, and top and bottom plates are cut to length and tacked next to the chalk lines.

15. The top and bottom plates are tacked next to the snapped chalk lines before laying out the wall components.

16. Framing members are nailed where the plates are marked.

17. Stud-and-block corner posts are constructed with full-length studs and blocks.

18. If the first stud of an exterior wall is placed 15 1/4″ from the corner and other studs follow 16″ OC layout, the edges of standard-size panels will fall over the stud centers.

19. When the second exterior wall is laid out, the 15 1/4″ mark is measured from the outside edge of the panel on the first wall. The corner of the first panel on the second exterior wall will align with the edge of the first wall panel. The opposite edge of the panel will fall on the center of a stud.

20. On partitions, the 15 1/4″ measurement ensures that standard-size gypsum board or interior finish panels will fall over the center of a stud.

21. The finish door opening is the width of the door and the distance from the head jamb to the floor. The rough door opening is the distance between the trimmer studs and the height from the floor to the header.

22. The finish window opening width and length is the frame-to-frame dimension. The rough window opening is the distance between the trimmer studs and the height from the rough sill to the header.

23. When laying out the width of a door or window rough opening at the corners of intersecting walls, allowances must be made along the corner assembly for the trimmer stud, side jamb thickness, and shim clearance.

24. When laying out the width of a door or window rough opening, the center of the opening is first laid out. One-half of the rough opening width, side jamb thickness, and shim clearance is laid out on each side of the centerline.

25. Floor plans provide information to properly lay out walls. Information on this floor plan is used in the layout calculations for Figures 43‑25 through 43‑28.

26. Wall plate locations are laid out and chalk lines are snapped.

27. Outside and inside corner posts are laid out and studs are laid out 16″ OC.

28. Studs are commonly laid out 16″ OC.

29. Rough door and window openings are located and stud, trimmer stud, and cripple stud locations are marked.

30. Rough door and window opening dimensions may be obtained from the door and window schedules on the prints.

31. A story pole is marked to indicate the lengths of studs, trimmer studs, and cripple studs. The example shown here is based on information in Figure 43-29.

32. Some prints provide only finish opening dimensions.

33. The story pole being laid out here is based on information found in Figure 43-31.

34. A bench is useful for making up large quantities of corner posts. The material should be held tightly against the fence and end block when pieces are nailed together.

35. Outside and inside corner posts are commonly assembled prior to wood-framed walls being assembled. Before nailing, align the ends of the studs.

36. Door openings are assembled before assembling the rest of the wall. In this example, cripple studs are required over the header.

37. The procedure for framing window openings is the same as framing door openings. A rough sill and bottom cripple studs are then added. Cripple studs follow the stud layout (usually 16″ OC).

38. A wood-framed wall is nailed together on the subfloor after corner posts and door and window openings are completed.

39. Joints in plates should occur over a full header or at the center of a stud or cripple stud.

40. The topmost plates of a double top plate overlap the plates below them at all inside corners.

41. A framed wall is often squared while it is lying on the subfloor. Temporary braces must be attached to keep the wall square while it is being raised. Wall sheathing may also be applied while the wall is lying on the subfloor to keep the wall square when raising it.

42. Diagonal metal braces may be used to provide additional wall stability. A shallow kerf is required for T- and L-shaped braces.

43. Wall plates and studs are notched for wood let-in braces. The braces are tacked in place when the wall section is lying on the subfloor. After the wall is raised and the brace adjusted to its final position, the nails are driven in.

44. Wall jacks can be used to raise walls when small carpentry crews are working on a job site.

45. A plate level is used to plumb a wall corner.

46. After the corners are plumbed, the tops of the walls are straightened using a line and 3/4″ blocks.

47. Powder-actuated fasteners are often used to fasten bottom plates to concrete slabs.

48. Metal framing angles attach wall studs to plates and concrete slabs.

49. Stud plate ties secure wall studs to plates.

50. Seismic or hurricane ties are required in areas that experience earthquakes and high winds.