load bearing header size chart exterior wall
## Load Bearing Header Size Chart for Exterior Walls: A Guide to Structural Integrity
### Introduction
When building or renovating an exterior wall, understanding the appropriate load-bearing header size is crucial for ensuring structural integrity. A load-bearing header is a horizontal support beam that transfers the weight of the wall above it to the supporting vertical studs. Choosing the correct header size is essential to prevent sagging, cracking, or even collapse.
### Load Requirements and Span Length
The size of the header is determined by two key factors: load requirements and span length.
**Load Requirements:**
* **Dead Loads:** Permanent loads such as the weight of the wall structure, siding, and insulation.
* **Live Loads:** Temporary loads such as wind, snow, and people.
The building code for your area will specify the minimum load requirements for exterior walls.
**Span Length:**
The span length is the distance between the supporting studs. A longer span requires a larger header to support the increased weight.
### Header Size Chart
The following chart provides recommended header sizes for exterior walls based on span length and dead and live load requirements. Consult the building code for your location for specific requirements.
| Span Length (ft) | Dead Load (psf) | Live Load (psf) | Minimum Header Size |
|---|---|---|---|
| 4 | 20 | 20 | 2x8 |
| 6 | 20 | 20 | 2x10 |
| 8 | 20 | 20 | 2x12 |
| 10 | 20 | 20 | 2x14 |
| 12 | 20 | 20 | 2x16 |
Note: These are minimum recommended sizes. Larger headers may be required depending on specific design considerations or building codes.
### Header Materials
Load-bearing headers can be made from various materials, including:
* **Lumber:** Solid wood is a traditional choice, but it can split or warp over time.
* **Laminated Veneer Lumber (LVL):** Engineered wood composed of multiple layers of veneer glued together, providing superior strength and stability.
* **Plywood Boxes:** Boxes constructed from plywood sheathing with framing members inside, forming a lightweight and economical option.
### Installation Tips
* **Use shim spacers:** Place shims between the header and the studs to ensure even weight distribution.
* **Nail or bolt securely:** Secure the header to the studs using nails or bolts spaced at regular intervals.
* **Flash the header:** Install flashing around the header to prevent water infiltration.
* **Use a ridge beam:** For longer spans or heavy loads, consider installing a ridge beam above the header to provide additional support.
### Real-Life Scenarios
* **The Leaning House:** A homeowner noticed a crack in their exterior wall and discovered a sagging header due to an inadequate size for the load requirements.
* **The Snow Storm Surprise:** An unusually heavy snowfall caused a collapse of an exterior wall when the header was too small to bear the weight of the snow.
* **The Window Wizard:** A clever contractor saved on material costs by using plywood boxes as headers for a row of windows, providing ample support while keeping the construction lightweight.
### Conclusion
Choosing the correct load-bearing header size for exterior walls is essential for structural safety and longevity. By understanding the load requirements, span length, and header materials available, you can ensure a strong and stable wall that will stand the test of time. Refer to the load-bearing header size chart provided for guidance, and consult with a qualified professional for any questions or specific design concerns.