Exterior walls are typically framed using vertical studs, horizontal plates, and headers around openings like windows and doors to create a strong, load-bearing structure.
Framing an exterior wall involves assembling the skeletal structure that supports the siding, insulation, and interior wall finishes. Here's a breakdown of the process:
Key Components
- Studs: These are the vertical framing members, usually 2x6 lumber (or sometimes 2x4 lumber depending on climate and building codes), spaced typically 16 or 24 inches on center (OC). They provide the primary vertical support.
- Plates: These are horizontal boards that run along the top and bottom of the wall.
- Bottom Plate (Sole Plate): Attached to the subfloor, it provides a base for the studs.
- Top Plate: The top plate is at the top of the wall. Often there are two top plates, called a double top plate, that are overlapped to tie wall sections together for added strength.
- Headers: These are horizontal beams installed above door and window openings. They transfer the weight of the structure above the opening to the studs on either side. The size of the header depends on the width of the opening and the load it needs to carry.
- Cripples: These are short studs that run above headers and below window sills.
- Sheathing: Plywood or OSB (oriented strand board) is attached to the exterior of the framing to provide racking strength and a nailing surface for the siding.
Framing Steps:
- Layout: The wall location is marked on the subfloor.
- Cut Lumber: Studs, plates, headers, and cripples are cut to the required lengths.
- Assemble the Wall: The bottom plate and top plate(s) are laid out, and the studs are placed between them at the specified spacing (16" or 24" OC). The entire wall is then nailed together.
- Frame Openings: Headers are built and installed above door and window openings. Cripple studs are added above the header to the top plate and below the sill to the bottom plate.
- Raise and Secure the Wall: The framed wall is raised into its vertical position and plumbed (made perfectly vertical). It's then nailed to the subfloor and adjacent walls.
- Sheathing: Sheathing is attached to the exterior of the studs, plates, and headers.
Example:
Imagine a section of exterior wall with a window.
- Vertical 2x6 studs run from the bottom plate to the top plate(s).
- A header spans the opening above the window, supported by vertical studs on either side of the window.
- Short "cripple" studs run from the top of the header up to the top plate.
- Below the window, a horizontal sill is framed. Cripple studs support the sill, connecting it to the bottom plate.
- The entire assembly is covered with sheathing for strength and weather protection.
By carefully assembling these components, exterior walls provide structural support, create openings for doors and windows, and provide a surface for attaching exterior finishes.
