Wood lintels are vital aspects in construction, as they can support the weight of walls or other structures above an open area (doors and windows). Builders, architects and homeowners alike should understand what wood lintels are, how they operate, their advantages and disadvantages – so that they can help when selecting the right material for their building project. In this article, we will define wood lintels, describe types of wood, review benefits and disadvantages, as well as explain how wood lintels are used in modern construction.
What is a Wood Lintel?
A wood lintel is essentially a horizontal piece of wood placed over windows, doors and other openings in a wall to support the load of the wall or structure above these openings. The lintel bears the load of the wall or upper structure and is part of the structure’s support framework, with pressure or load being transferred to columns or supports adjacent to the opening. Lintels are a critical part of the structural integrity of the wall and prevent cracking and potential collapse caused by the pressure on the opening.
Common Types of Wood Used for Lintels
Softwood
Softwood varieties have lower strength than hardwood, but can be used to build lintels across openings with small spans. A few common types of softwood used in lintels are:
- Pine: This is one of the wood varieties most frequently used for lintels due to its easy availability and low cost. Pine is relatively lightweight, easy to work with and has enough strength for most residential uses.
- Fir: Fir is known for its strength and stability and is also a popular wood type used for lintels. It is strong and resistant to wear and can be used in load-bearing or non-load-bearing applications.
Hardwood
Hardwood varieties have much higher strength and can bear larger loads, making them ideal for longer spans. Some common types used in lintels are:
- Oak: Oak is a very dense wood that has a high value as it is incredibly strong, stands up to decay very well, and is a long-lasting wood. It is often used for lintels that require significant load-bearing capacity or where the look of the wood is a critical consideration.
- Ash: It is a hardwood type that has great resistance to shock and bending. Ash does not grow as frequently as oak does in general, but is another wood that is used when high strength is a requirement.
Advantages of Using Wood Lintels
- Aesthetically Pleasing: Wood lintels are visually pleasing, functional and match with many possible architectural styles. They can be left exposed without painting to obtain a natural, rustic feel.
- Cost-Effective: Wood is often a less expensive option than other materials used for lintels. Therefore, it can be a preferable option for budget-friendly projects.
- Easy Installation: Wood lintels are quicker to cut and install than lintels made with other materials like concrete and brick, which require more labour and time to build. This can save on labour costs and time in new construction.
- Sustainably Sourced: Wood is a renewable resource and certified wood from responsibly managed forests typically has a smaller carbon footprint than non-renewable source materials like concrete or steel.
- Thermal Insulation: Wood is a better thermal insulator than concrete or steel, offering better energy efficiency in buildings as there is less heat loss or gain through openings.
Disadvantages of Using Wood Lintels
- Vulnerability to Moisture Damage: Wood is subject to rotting, warping and swelling from moisture. Wood lintels subjected to moisture over long periods of time can degrade over time, until they are treated, or properly protected
- Low Load Capacity: While wood can carry loads well in excess of 6000 lbs, wood typically does not have the load bearing capacity of reinforced concrete or galvanized steel. So if your structure needs to bear significant loads, wood lintels may not be adequate.
- Life Expectancy: As you know, wood is affected by exposure, including sunlight, moisture, and insect attack. Therefore wood lintels may not age as well as alternative lintel materials like alloy steel or concrete.
Applications of Wood Lintels in Modern Construction
In residential construction, especially in low-rise buildings where the load isn’t as high, wood lintels are commonly used. Examples of applications include:
- Door and window openings: Wood lintels are most commonly associated with residential construction, where they serve the purpose of stiffening openings. They provide structural benefits and serve an aesthetic design feature to the building facade.
- Renovation or restoration projects: In existing buildings or heritage structures, a wood lintel can offer a traditional appearance and feel while providing support to the opening as intended in contemporary construction practices
- Light-weight construction: In non-bearing walls, or when the wall system bears only nominal loads, wood lintels are economical and practical.
- Architectural styles: Wood lintels can be manufactured to suit unique openings or tailored to a custom-designed system. They are flexible and appropriate solutions for these situations.
Installation of Wood Lintels
Correct placement of wood lintels is essential to the structural stability of the opening as well as the building itself. Precise and careful installation is necessary to be certain the load is carried correctly and safely. Here is a more a detailed breakdown of the installation methods:
- Measure the Opening: Precise measurements are the primary and foremost stage. In order to achieve accurate fitting, measure both width and height at the position where the lintel will be installed. If the lintel is used to support a door or window, measure the appropriate opening size while also considering the sizes of any cladding, plaster or finishing. Also consider wall thickness, insulation, or any other impediments surrounding the lintel measurements.
- Prepare the Lintel: Depending on the load considerations, site conditions and the desired aesthetics, a wood type should be selected. The wood type will be either softwood, hardwood, or engineered wood. Once you select the wood type, cut the lintel to length.
If using solid wood, it is recommended to treat the lintel with an appropriate preservative, with the intention of providing a second layer of protection against moisture, decay and pest infestation. The use of an initial treatment would be especially prudent for lintels used in exposed scenarios, and for lintels exposed to humid environments.
- Prepare the Structural Supports: Check the load bearing walls where the lintel will sit. The lintel must have solid bearing here. It is essential to ensure the bearing points are level and structurally adequate to support the weight of the lintel and the load it is carrying. If necessary, provide temporary shoring or supports to hold the lintel in place until it is installed.
- Position the Lintel: Lift the lintel into place, ensuring it is precisely over the opening, centred and directly above the structural support on both sides. The lintel should extend comfortably (usually around 150-200 mm) over both sides of the opening, thereby transferring the load onto the supporting columns or side walls.
- Check for Level and Alignment:Using a level, verify that the lintel is level. If it is not level, it could put stress or strain on the structure that will create issues such as sagging or even cracking of walls in the future.
- Fix the Lintel: Secure the lintel to the supports. This is commonly done with screws, heavy-duty nails, or bolts depending on the type of fastening. The fastening method for engineered wood products, such as LVL, may need special fasteners. The lintel should be anchored well, but avoid over-tightening fasteners, which can split or crack wood.
- Ensure Proper Load Distribution: Once the lintel has been installed, be sure that the load above the lintel is distributed evenly over the entire length. If the lintel is installed at a slope, or the load is not equally distributed, it is possible that the lintel will bow or fail eventually.
- Finishing and Final Inspection: You may wish to apply final treatments if necessary. If the lintel is exposed to the outside environment, it might be appropriate to sand it for aesthetic purposes and then seal or paint it to protect it.
- Remove Temporary Supports: You can now remove any shoring or temporary supports used while installing the lintel.
- Additional Considerations: If the wood lintel is part of a larger structural enclosure, make sure it integrates well with the other materials there. This may include some kind of additional reinforcement or bracing to account for stability of the whole framework.
- Weatherproofing and long-term care: If the wood lintels are exposed to the weather or even very wet air, apply weatherproofing coatings, conduct regular maintenance checks and periodic reapplication of preservatives.
Conclusion
Wood lintels are an ideal option for residential construction, with a combination of moderate strength, a nice appearance and inexpensive construction costs. However, their use must be approached carefully in terms of potential for moisture, and especially pest damage, in the construction environment. When installed correctly and treated adequately, wood lintels can provide a long-lasting and sustainable option for supporting openings, specifically doors and windows. By understanding the various wood lintels types, benefits, and limits, builders can feel more comfortable when determining the long-term safety and trustworthiness of openings such as doors and windows.