Many times timber frame home owners, craftsmen and builders will liken the timbers used in building a house with fine furniture. While the craftsmanship and detail that goes into these structures is often comparable to furniture construction, the timber frame finishes that are used to protect and preserve the wood are far different than what is used in the furniture industry.
There’s a big difference between the kiln dried, dimensionally stable lumber that’s used to create your furniture and the heavy timbers used to build your home.
Wood used in furniture building is kiln dried and will have little shifting, swelling or shrinking. Varnishes, urethanes and lacquers seal the wood to maintain the moisture level in the wood and protect the surface from damage.
Lumber used to build a timber frame home needs to breathe. It moves because of varying moisture content in the cells of the wood, stresses that are caused by the building itself and the changes in atmospheric pressure and temperature.
Green timber attempts to maintain moisture equilibrium. The chemical composition of the green wood and the constant dispersal of moisture will eventually oxidize and break down a finish that seals the wood.
If the builder is using re-sawn lumber, the reverse process occurs. The dry timber fibers will absorb moisture from the air. The wood needs oils to reduce brittleness and provide moisture as new movement and stress factors from the re-purposing come into play.
The Purpose Of A Wood Finish On Timber Frame Lumber
Whether you’re using green wood or re-cycling lumber, there are three objectives in the finishing process of your structure.
Foremost, the wood must be stabilized. The goal is to minimize the shrinking process, slow down drying and reduce checking. This ensures that all the joinery remains tight and there is no danger of shifting, movement or cracking to the point of instability.
Second, a finish is used to enhance the beauty of the wood. You want your house to look its best, and finishing the wood to play up the natural colors, grain and texture increases the charm of your unique and distinctive home.
The third objective of a good finish is its ease of application. Although this is a job that isn’t performed often, it’s a big undertaking. Maintaining and refinishing all that wood over the years is certainly something to consider when choosing a finish for these massive and towering timbers. As well as being easy to use, the finish should be safe for both the environment and those who take on the refinishing task.
Timber Frame Finishes – Products That Protect Your Investment
Most commercial products contain driers to speed up the drying time of the finish. Typically, these finishes are mostly solvents with very little protective material and require a number of applications. This effectively seals the surface of the wood. The metallic driers are also toxic. These products are not a good choice for your timber frame home.
Choose a penetrating oil finish that is drier-free, so the wood has ample opportunity to absorb the oil. You should be able to apply it easily and quickly to a large surface, and excess product should be easy to wipe off without lap marks or a buildup of gummy residue on the surface of the wood. This type of natural oil finish continues to wick into the fibers of the wood long after the surface is dry.
Use only pure ingredients to ensure there is little discoloration over time. This kind of finish remains flexible, resilient, allows the wood to breathe, and absorbs into the cell structure of the wood.
Land Ark oil is a great natural product and is widely used in the timber frame industry. Check it out at Heritage Natural Finishes.
Exterior Surfaces Require Extra Protection
The outside of your timber frame home requires protection that goes beyond the penetrating oil finish you’ve chosen for your interior surfaces. You need to protect the wood from the effects of sunlight, mildew and insect damage, as well as maintaining the moisture level and minimize the checking and shrinking.
Unless you live in a very arid part of the country, your wood finish should have a mildewcide. These exterior products should be fortified with a wood preservative to resist and kill mildew, mold and fungus.
Regardless of where you live, your exterior finish should have UV protection. This additive protects the wood against the deteriorating effects of the sun’s rays and helps to decrease the natural graying of the wood. If your home is situated in an area where termites or other insects are a problem, you may need to spray the wood with borax or other pesticide before applying your wood finish.
Choose well and choose wisely when deciding which finish is right for you and your timber frame home. Do your own research, ask questions and get the latest data sheets of product specifications. Don’t shortchange yourself or your home, as the consequences of a poor choice can haunt you for decades.