Wood Species for Your Timber Home

Several wood species are accepted in the timber frame and post and beam home industry.  Each species carries its own characteristics and beauty.

Douglas fir timber frame

Douglas fir: Known for its structural strength, Douglas fir’s color ranges from a yellow to orange-brown to deep reddish brown and has a limited number of knots.  Douglas fir checks and cracks minimally compared to other wood species. Large Douglas fir timbers may be designated FOHC (free of heart center) which means that the usual 'bulls eye' heart wood found in the center of most beams is absent. Free of heart timber also checks less and is more stable than timber which does have heart wood.

Eastern White Pine:  A blond wood with knots of various sizes and occasional red streaks, EWP is a stable, soft wood that is a favorite choice in the Northeast.  Not as strong as Hemlock or Douglas fir, Eastern White Pine is a light wood which cracks and checks as it dries over time giving a more rustic look. 

Western Red Cedar:   This species ranges from medium to dark brown in color.  It is saturated with a natural preservative, which allows it to repel water naturally.  This keeps shrinking and swelling to a minimum and limits warping and twisting.  Its close, even, straight grain makes it easy to work and finish to a smooth, silky finish.  Western Red Cedar is generally free from pitch and holds stains and paints beautifully.

Eastern Hemlock:  Hemlock is strong and less expensive than Douglas fir; however it carries a defect called “ring shake”.  Ring shake is a lengthwise separation that occurs between and parallel to growth rings which usually appears after a year or so.  Colors range from a pale brown to faintish reddish brown, which darken over time. 

Red Oak:  Red Oak is light brown with red undertones which gives an antique look.  Oak is a relatively heavy and strong hardwood, but tends to twist, crack, and check more than most softwoods.

Southern Yellow Pine:  Southern Yellow Pine is a very popular wood species for a timber frame or post and beam home.  Available in long lengths and with consistent high quality, it has a bold grain pattern and color ranging from golden brown to reddish brown which darkens with age.  When dried properly, Southern Yellow Pine twists and checks very little and stains very well. Most Southern Yellow Pine used in timber frames is now from salvaged or reclaimed structures.

Whatever your selection in wood species, you can be assured your timber home will be beautiful!

Timber Homes: More than a House

A timber home is much more than a house providing shelter; it is an expression of the owners’ way of life, a representation of their families and personalities.  

At first glance, a timber frame home may look like any other home in the neighborhood (especially if it does not feature a timber entry, a timber porch, or timber accents on the exterior).  Upon entering a timber home, though, most guests are rendered speechless.  Some do try to speak or manage to exclaim a whispered “wow!” under their breaths, but the emotion is always the same:  admiration. 

Timber homes are

• Undeniably beautiful
• Traditional, nostalgic

They offer

• A sense of permanence
• Versatile, open floor plan

They also

• Describe interior space
• Create ceiling planes

Timber homes appeal to our sense of tradition and desire to understand structure, but perhaps the more obvious features are their warmth and comfort. 

If you are planning to build a timber frame home, consider using an architect for the home design.  See some of our timber homes and architectural services on our website!

November Timber Home Show

If you live in Connecticut, Massachusetts, or the Albany, New York area, check out The Log & Timber Home Show in West Springfield, Massachusetts this November!

Bonin Architects will be exhibiting in Booth #334.  Stop by and see us!

 The Log & Timber Home Show

Eastern States Exposition

West Springfield, Mass

November 19-21, 2010

Friday, Nov 19: 11:00 AM - 6:00 PM

Saturday, Nov 20: 10:00 AM - 6:00 PM

Sunday, Nov 21: 10:00 AM - 4:00 PM

Also, look for a free seminar presentation by Architect Jeremy Bonin on "Designing Your Timber Home", Saturday at Noon.

Need directions?  Click here

Ticket information?  Click here

About Jeremy Bonin, AIA NCARB LEED AP:

Jeremy Bonin, a principal partner of Bonin Architects & Associates, is an award-winning architect and the author of TIMBER FRAMES: Designing Your Custom Home, which was written to help homeowners become fully involved in the design of their new timber frame or post and beam home.  Jeremy has a special interest in sustainable design and green homes with a specialty in structural insulated panels and timber framing while incorporating other sustainable (green) energy practices, including geothermal, solar, radiant heat, and energy-efficient foundation systems. 

Timber Home Wins Dream Home Award

The 2010 Dream Home Awards recently awarded 33 builders, architects, designers, developers and tradesmen from across the nation for their excellence in a variety of areas.


Award categories included Historic Renovation of the Year, Conceptual Projects, Community of the Year and Best Green Home Project and were judged on Unusual or Creative Architectural Design Elements, Creative Site Solutions, and Exterior and Interior Appeal.


Our Lincoln, New Hampshire timber home won a Silver Award in the Custom Vacation Home category.

This 4800 square foot home was designed by timber frame architect Jeremy Bonin within strict Architectural Review Board guidelines which dictated architectural style, building height, setbacks, exterior materials, and color schemes. The small, ½ acre corner lot restricted onsite material storage. Pre-built Structural Insulated Panels were used for their energy efficiency and fast installation time (providing a weather-tight shell in just two weeks), allowing the site to be kept free from materials being stored long-term throughout the construction process.


Bonin Architects, along with 31 other talent professionals, were awarded for their outstanding work based on factors such as quality of design, livability, sustainability and the ability to provide healthy and nurturing environments for consumers. Dream Home Awards aims to assist and encourage building industry leaders to develop innovative homes and products.

Custom Timber Home, Lincoln NH

Architect Jeremy Bonin's talents reach beyond home design and expertise in energy efficiency and green building - he's also a talented photographer.  Here are some photos he took of a timber house he designed in South Peak Resort, Lincoln, New Hampshire.  Enjoy!

Are you interested in building a timber house?  Visit our website for information on our architectural services and fees.
~Jackie Lampiasi, Marketing Director

Television Interview with NH Architect Jeremy Bonin

Kearsarge Valley Magazine recently interviewed Jeremy Bonin about our architectural services for timber homes. Watch the interview here:




For more information on Bonin Architects, including our architectural fees, please visit our website! We'd love to hear about your plans to build an energy efficient timber home!

Timber House: Factors Impacting the Home Design

There are two basic factors in timber home design: fundamental and elemental. Fundamental considerations are tangible. For example, how many people will be living in your home? How much do you wish to invest, both financially and emotionally? Is it a timber house you’ll use after retirement, which might dictate single-level living? Only you can determine the emotional investment you’ll have in the house. This varies from person to person and typically affects how much day-to-day input you’ll have in the home’s development.

Elemental considerations are less tangible. The three I find most important are light, views and permanence. Light makes visible the spaces we inhabit. Light also has its own characteristics such as intensity, color, texture and depth, so light and its absence must be considered when designing. For example, if you have two identical rooms—one on the east side of a house and one on the west—each space will be perceived differently, even if they have the same colors, furnishings, textures, volume and design. Yes, it all comes down to sunlight. For example, if you’re not a morning person, it might not be a wise move to place your bedroom on the east side of the house.

Views come next. One of the advantages of a timber home is the ability of timbers to frame views of different spaces. A pair of posts might define the entrance from the dining to the living room; and a floor girder might delineate the dining from the living room in the same manner, acting as a soffit between different ceiling heights. Our experiences in a space often are based upon what we see or feel from it even before we enter a room.

The last is permanence. Obviously, a home is more than shelter. It can be a place of retreat and serenity, and when we can see and understand the structure that protects us—the posts, beams and braces—we gain a primal understanding of security. Again, many timber homes built long ago are still around today. We might not understand the comfort and security these structures provide, but we all perceive and feel those qualities the minute we set foot in one of these homes.

Timber Homes: Beautiful & Unique

If you are looking to build a stunningly unique home, consider a timber frame home. Timber homes, also called post and beam homes, are both beautiful and distinctive.

The timber frame is wrapped in an insulating barrier, usually Structural Insulated Panels (SIP Panels). The timber structure is then visible on the inside of the home, creating one of the most beautiful home interiors available.

Unlike man-made materials, timbers vary in color and size, adding depth and warmth to the home. Posts and beams can be recycled from old factories, barns, and historical buildings, adding character and bringing a unique history to the home. Small defects may be present, including nail holes, notches, and scratches, which also to the beauty of the home.

Timber frames offer elegant, simple solutions to challenges that exist in designing a home, allowing homeowners to create every type of space imaginable, from grand and expansive to small and cozy, public to private, recreational to functional. Timber frames appeal to those concerned with the quality, not quantity, of space.

Timber homes address the basic human need for shelter and comfort while satisfying our deeper desires for simplicity, tradition, security, warmth, and beauty. Best of all, timber frame design can accommodate any architectural style to reflect your personal taste!

Timber frame home, top, by Riverbend Timber Framing

Timber Homes and Green Building

There is a natural fit with timber frame, SIP Panels, and green building.

Posts and beams can be recycled from old factories, barns, and historical buildings, adding character and a unique history to the home and showing respect for our limited resources. Timber homes are green, in that they last for centuries (there are some Asian timber frames built in the 6th and 12th centuries still standing today). Rather than having to be rebuilt in 50 years, the timber frame home’s exterior could be updated and the interior completely renovated several times while the timber frame remains structurally sound and beautiful. As added benefits, the timber frame addresses quality issues, brings warmth to the house, and also aids in delineating spaces and gives an order and rhythm to the home.

SIP panels address the efficiency of the home and can be used in any climate. The structural insulated panel enclosure system creates a thermal envelope around the timber frame, keeping your home warm in the dead of winter and cool in the hot summer months. (SIPs were even supplied for the International Science Station at the South Pole, where summer temperatures average minus 20 degrees Fahrenheit!) The insulation used in SIP panels is a lightweight rigid foam plastic composed of 98% air, and requires only a small amount of petroleum to produce. Also, the foam insulation is made using a non-CFC blowing agent that does not threaten the earth’s ozone layer. Since SIPs are prefabricated in the factory, there is less jobsite waste that needs to be landfilled. Most SIP panel manufacturers recycle factory scrap to make other foam products.

There are many quality timber frame and SIP panel manufacturers around the country, allowing homeowners to work with a company near them, reducing the amount of travel required for the material to get to your site.

As far as the timber home’s space, additional features, and systems, your green architect will give you numerous options in the green building process to save money and protect your investment.

Building a Timber House

Building a timber house isn’t much different than building any green home. The steps are the same: design, build, enjoy.

Design
Hiring a licensed architect, particularly a timber frame architect, will quite possibly be the wisest choice you can make to build a timber house. A timber frame architect provides five valuable services:

• 1. Understands the Scope of the Project: A licensed timber frame architect understands timber frame construction as well as the details and phases of the project. He or she has the expertise to develop and refine the vision so you can understand the scope of the project.

• 2. Knows State and Local Codes: A licensed architect is knowledgeable in the building codes applicable to your project and designs the timber frame to meet these codes. They usually prepare most of the documentation necessary for you to get your building permits, saving you both time and money.

• 3. Hires the Team: When you secure an architect’s project management services, he or she heads the team and makes sure everyone knows their job. They answer the myriad of questions from the builder and their subcontractors, and makes sure any changes do not affect the structural and architectural integrity of the timber frame design.

• 4. Oversees the Project: The licensed architect is involved in the day-to-day construction of the project, making him or herself available for consultations, meetings, and questions from the site. Some architects will also hire the subcontractors for you (to erect the timber frame and install the Structural Insulated Panels, for instance) and then establish and manage the construction schedule. Throughout the project, your architect is your advocate, staying true to your home design and your budget.
  
  
• 5. Can Green Up Your Project: Are you interested in building a green timber house? A green architect will give you numerous options for saving money and protecting your investment in the home design and material selection processes.

Build

The second step of building a timber frame home (design, build, enjoy) is pretty much the same as building a green home.

Your timber frame architect can guide you through the construction of the timber house, overseeing the day-to-day construction of the home, managing subcontractors, and the project schedule. The timber frame architect manages on-site changes to make sure they 1) are in keeping with the original home design; 2) work with the timber frame design; and 3) are changes you can afford.

The timber frame and SIP panels are generally completed in two to three weeks, depending on the home size. After that, the construction of the rest of the home (roofing, siding, windows and doors, trim, etc.) is the same as any green home.

Enjoy
The final step, which can last for generations, is definitely the most satisfying phase of building a timber house. This is when you truly enjoy the personal touches you put into the home, the little details you insisted on, the private areas you have for personal time, and the open common areas where you strengthen relationships with the ones you love.

(photo of finished timber home, right, courtesy of Timberpeg)

Types of Timber Framing

There are two general types of timber frame systems, each having several variations: Common Purlin systems consisting of King Post, Queens Post (see modified Queen Post Truss below), and Hammer Beam frames for example, and Common Rafter systems such as Collar Tie, Principal Purlin, and Ridge Beam frames. There are many reasons to choose one frame type over the other and costs vary as well.

Common Purlin systems, or timber frame bents, are typically assembled on the first floor deck, then raised as whole units into place by a crane (see photos bottom), connected with the joinery, and secured with wooden pegs. Because of the structural integrity of these bents, this system of timber framing allows for an open, flexible floor plan.

Common Rafter systems are raised either as ‘walls’, one timber at a time. Timbers are erected in succession; one end post erected first, then a connecting beam at the second floor level is secured to the post, then another end timber is joined to the beam. Timber ends are fastened with some form of mortise & tenon joinery. Joints are typically fastened with pegs, which can be cut flush to the joinery or left protruding for decoration.

If you already have a timber frame design in mind, most likely the design will dictate which kind of timber frame will be used according to spans and interior walls; however if you would like to incorporate a specific timber frame (or a combination of timber frames) into your home design, your timber frame architect can design the home around the timber frame.

Timber Frame Homes and LEED

LEED (Leadership in Energy and Environmental Design) is the most well-known, visible rating system for energy efficient, high performance buildings today. A program of the US Green Building Council, LEED is taking the lead in educating professionals and consumers in the green building movement.

Can a timber frame home be LEED certified? Absolutely. LEED for Homes awards certification based on point totals in eight categories. Categories include:

• Innovation & Design Process
  
• Location & Linkages
  
• Sustainable Sites
  
• Water Efficiency
  
• Energy & Atmosphere
  
• Materials and Resources
  
• Indoor Environmental Quality
  
• Awareness & Education

An important first step in building a LEED timber frame home is to interview and hire a LEED architect registered in your state to design your home. After you have a timber frame design, your architect will help you find a qualified builder to construct the timber frame home and document certification points throughout the construction process. When the home is completed, a certified Rater inspects, tests, and certifies the home as Certified (45.0 points), Silver (60.0 points), Gold (75.0 points) and Platinum (90.0 points).

Energy savings is just one of the benefits of a LEED certified home. A green home that reaches a LEED Certified or LEED Silver status will enjoy a 30% reduction in energy usage over a conventional home. A LEED Gold home increases that savings significantly, using 48% less energy, while a LEED Platinum status home can see the biggest energy reduction - 50%-60%. (Home Energy Rating System (HERS) scores compared with International Energy Conservation Code standards).

Jeremy Bonin, AIA NCARB LEED AP
Registered in NH, VT, ME, MA, NY, RI, and PA

Douglas Fir Timbers – a Good Choice!

Douglas fir is certainly one of the most popular wood choices for a post and beam or timber frame home because of its structural integrity and handsome appearance. Structural posts and timbers are graded according to the American Lumber Standard Committee, Inc. through accredited agencies such as the Western Wood Products Association’s (WWPA) lumber grading rules.

A structural timber’s strength is graded for strength or physical appearance. After a timber passes through a planer for surfacing, an inspector evaluates all four sides and the ends of the timber before assigning it a grade. The inspector looks at:

Wood characteristics: both natural growth and imperfections

Knots: checked for size, location, displacement, quality, and occurrence

Holes: (where knots have fallen out), for size and location

Wane: the presence of bark or the lack of wood fiber along the edge of the timber

Splits, Shakes, and Seasonal Checks: separations in the wood that can affect the structural integrity of the timber

Slope of the Grain: the deviation of the line of fibers from a straight line parallel to the sides of the timber

Warp: a bow, crook, twist, or cup in the timber

The way a timber is sawn is relative to its structural integrity. We recommend only “free of heart center” FOHC timbers, which means that the usual 'bulls eye' heart wood found in the center of most beams is absent. Free of heart timber also checks less and is more stable than timber which does have heart wood.

Consult with your timber frame architect on which wood species and grade is appropriate for your home!

Five Tips to Building Your Timber Frame Home Within Budget

You’ve established your budget for your new timber home and your architect and builder say it can be built for that amount – but how do you stay true to that magic number? There are several things you can do to help you stay within your budget during the home design process:

1. Divide the total budget by the square footage of your timber frame house, and stay within that dollar amount for each square foot of space. Work with your timber frame architect and builder to stay within allowances.

2. Keep the home design simple. If you have a tight budget, keep the design straightforward and uncomplicated. Dormers and complicated roof systems add significant cost. Minimize the home’s footprint. Instead of a sprawling one story home, reduce the footprint by shrinking the floor plan and adding a second story. This doesn’t mean your timber frame design has to be a box – unless, of course, you want one.

3. Consider a hybrid home by combining building methods; i.e. use timber framing in public areas (great room, dining room, and kitchen) and use SIP panel construction or conventional material in other areas.

4. Glazing = $$$. Windows are a huge expense and come in a variety of designs, styles, and energy efficiency ratings. For residential and light commercial projects, aluminum clad wood windows are the preferred choice. To stay within budget, work with standard window sizes, avoiding oversized, custom units. Beware: hardware upgrades can be costly.

5. List your priorities and allocate amounts to each room or system. If it’s your heart’s desire to have a cathedral timber frame great room with a wall of windows, you can allocate a larger amount of money for that area and limit spending in other areas (perhaps on fixtures in the kitchen and bathrooms).

Your timber frame architect and builder are knowledgeable in the many materials and systems that go into your timber frame home. They will be able to offer comparisons on materials, including their costs and life cycles (for example, a metal roof that will last 40 years but cost more up front vs. a shingle roof that will last 25 years but cost less), so you can make educated decisions which will affect your bottom line.

Knowing all of your options will make it easier to stay within budget on your timber frame project - and, with careful planning, you can have a beautiful, energy efficient timber frame home within your budget.

Advantages of Timber Framing

Let’s face it: timber frame homes are gorgeous. In addition to their inherent beauty, timber frames have several advantages over homes built with conventional materials. Here’s our list of the top five advantages:

1. Timber frame homes never go out of style. While other building fads phase in and out, timber frames have lasting beauty and can be easily adapted for new uses over time. Timber frames allow you to create every type of space in a home you could want – from grand and expansive to small and cozy, public or private, recreational or functional.

2. Timber frames with SIPs (structural insulated panels) are energy efficient in all climates. A structural insulated panel enclosure system creates a thermal envelope around the timber frame, keeping your home warm in the dead of winter and cool in the hot summer months. Bad weather? Bring it on!

3. Posts and beams can be recycled from old factories, barns, and historical buildings, adding character and a unique history to the home and showing respect for our limited resources.

4. Timber frames stand the test of time and have endured centuries of humankind, with 13th century timber frames still standing today. That’s over 800 years – which proves true the industry’s claim that timber frame homes will be enjoyed for generations to come.

5. Because of the strength and integrity of the structure and with modern engineering, timber frames can stand against hurricanes and hurricane force winds, heavy snow accumulations, and even earthquakes, making them one of the most durable building types available. They also offer greater flexibility in the design of the floor plan, allowing for open floor plans and wide open spaces.

Ready to start your timber frame home design? See our Architectural Services & Fees for information on how Bonin Architects & Associates can design and build a healthy, energy efficient home that gives you a great return on your investment!

Your Custom Timber Frame Home – How Should it Feel?

A home fulfills many purposes, but it can also satisfy numerous personal, aesthetic, and emotional requirements that can be difficult to describe in words. In starting to imagine your home design, it will help your timber frame architect if you identify and communicate how you want each space to feel. How?

You may find it a challenge to explain how you want a room to feel. Start by doing some simple exercises. (This exercise is the same for timber frame homes, post and beam homes, conventional homes, panel homes, and other building types.)

Pick up a home magazine or imagine a home you are familiar with. Find a room you like. What do you like about it? The way the afternoon sunlight casts shadows within the room? The room’s intimacy or its abundant space?

Think about other spaces you enjoy – the park, the library, your friend’s home. How does the space make you feel? What creates that feeling? Be specific, and write down what you like about it. For instance, you might write, “I like how the color tones of the timbers change as the sun sets” or “I love how the outdoors is brought inside”. These small realizations will help the home design to evolve from a floor plan to a custom home that is an extension of your life philosophy.

Do this for each room in your home design. It is also helpful to describe what you don’t like about certain floor plans, rooms, or space. For instance, if you are not fond of having to walk through your closet to enter your Master Bedroom, document this. Perhaps you like the great room in a magazine photo but you want the timbers to be the center of attention, not the television. Or, you may like the space but find it lacks the intimacy you’re looking for in your home – a cozy corner where you can chat with another couple, a well-lit reading area, or a secluded spot for your cell phone chargers, mail and telephone.

Keep all of your notes together. Cut out full pages or small photos that describe your likes and dislikes. As you go through this process, you can update your thoughts with text and photos. Eventually, you will come to a good understanding of what you want your custom timber frame home to look and feel like. Bring your notebook to your first meeting with your timber frame architect. Starting with your vision in hand will expedite the design process while guaranteeing success.

Your timber frame architect will spend time with you to guide you through this process and will translate your ideas into a preliminary design for your consideration and review. The result will be much more than a home with a standard floor plan – you will have a custom home that matches your philosophy and lifestyle, a reflection of who you are, your dreams and aspirations.

Have you signed up for our FREE Home Seminar?

Photos courtesy of Riverbend Timber Framing.

Jeremy Bonin, AIA NCARB LEED AP

Bonin Architects & Associates, PLLC

Why Choose a Timber Frame Home?

Would you like to build a home that addresses much more than the basic requirement of shelter? Consider a timber frame home.

No matter the size, a timber frame home leaves guests sighing with open jaws as they enter. A timber frame represents hospitality and functionality while doing much more.

The timber structure can define the spaces within the home. A common timber frame design requirement for most people is an open floor plan to encourage family interaction. The timber frame floor plan is versatile and designed with necessary timber supports located at strategic places – adjacent to interior walls, at the corner of the staircase, or to create a visual division between two rooms. Cathedral ceilings are common in timber frame homes, offering guests the opportunity to experience the depth and complexity of the timber system. The framing system creates ceiling planes which aide in delineating room layouts and add dimension and form to the space which conventional framing typically does not achieve.

The beauty of the timbers is undeniable and appeals to our sense of tradition and desire to understand structure. Options such as reclaimed timbers, choices in finishes such as hand hewing, and a variety of stain colors help you express your unique personal values and desires. If you love antiques and nostalgia, reclaimed timbers often carry a rich history and unique story. Their background, together with the imperfections they bear, offer an opportunity to showcase their longevity in your home’s structure.

Perhaps the most significant aspect of a timber frame home is that it will provide your family with warmth and comfort for generations!

Kimberly Bonin, Executive Project Manager

Bonin Architects & Associates, PLLC

Photos by Riverbend Timber Framing.

Timber frames – finishing touches

In addition to choosing a wood species for your timber frame or post and beam home, you’ll have to decide how you want the timbers finished.

There are several choices for the finish. Most prefer to have their timbers planed smooth and sanded on all sides for a clean finished look. You might, however, choose not to have them planed, and leave them rough sawn (not planed or sanded) for an antique look. For an even more traditional, antique look, timber may be hand hewn. Notches, or cuts, are made in the timbers using heavy hand tools such as an adze or chisel.

Most manufacturers offer the option of chamfered edges. A chamfer is made in the timber by cutting off the edge of the corners, either a simple flat 45 degree cut or a variety of other styles are available as well. Chamfers give the timbers a refined, sophisticated look as well as alleviate the sharp corner and possibility of splintering wood.

In order to protect the timbers’ natural grain, manufacturers typically apply a tung oil or stain after the joinery is cut. You can choose a clear stain or a darker color to match your preference and desired interior look. While the finish will be applied to all surfaces and joints in the beams at the manufacturer’s shop, an additional coat or two may be applied on site.

Whatever finishing options you choose, the beauty of a timber frame home is undeniable and will be the focus of the home’s interior.


Kimberly Bonin, Executive Project Manager

Bonin Architects & Associates, PLLC

Natural Features of a Timber

Timber is a natural material, and as such, is affected by its surrounding environment – its climate, area vegetation, and wildlife. For instance:

As timbers go through the drying process, they shrink or swell until they reach equilibrium with the constantly changing level of moisture in the air of its environment.

Water is stored in wood in two forms: 1) as free water in the vessels and/or cells, used to move nutrients within the tree; 2) as cell (or bound) water, which is an integral part of the cell walls (about 30% of the water). As the tree seasons, or dries, it loses its free water first. Then, as the water in the bound cells near the surface is exposed it evaporates and the wood shrinks at a faster rate than the cells deep inside the wood. Because of the cell structure, wood shrinks primarily in width and thickness and very little in length. This uneven loss of moisture may result in twisting and cracks called “checks”. These checks typically do not extend through the timber. Opinions vary as to “checking” adding character to the timbers. Either way, if you are considering green timbers for a timber frame or post and beam home, you can expect to have some checking occur.

Splits are large checks, or cracks, that penetrate through the entire thickness of the timber, most often occurring near the ends. Splits can occur from poor handling or by drying stresses (the cut end-grain of the timber releases moisture most rapidly). Because they reduce the strength of the timber, split timbers are unsuitable for most timber frame applications.

Knots: As a branch starts to grow from the trunk of a tree, cells in the trunk bend around the branch, leading to a knot in the timber that is cut through the young branch. Knots vary in quantity according to wood species and timber size. Typically they are not a structural concern; however, knots can affect the timber’s strength if they are found in or near joinery because the wood in the center of a knot may have lower strength and knots located near the edges of the timber may cause variations in the grain near the corners, resulting in a significant reduction of strength.

Some wood species (like hemlock) are subject to ring shake, which is the separation of the rings in a timber that occurs during the drying process. Hemlock, like other species, may be ordered “shake free” if desired, for an additional charge.

Storms producing high winds can bend trees enough to crack the layer beneath the bark, making an opening between the grains of wood. When this happens, pitch or sap can flow into the crack and then heal, creating a pitch pocket. Pitch pockets may be considered a defect in the wood and can compromise the structural integrity of a timber.

Bluestain is a blue-toned discoloration in softwoods, especially pines, occurring only in the outer part of the tree, the sapwood, closest to the bark. Many confuse this with mold, which can grow on the wood’s surface after it is processed; however, bluestain is caused by a type of harmless fungus. Bluestain does not affect the timber’s integrity, but where appearance is important bluestained wood may not be desirable.

Mold is one of the most common types of fungus on the earth. When stored in a humid setting, timbers, especially pine, are susceptible to mold. Stains or streaks of mold range from blue-black to blue-gray and can even be brownish or purple. Although the mold does not cause timber decay, the discoloration causes aesthetic concerns as well as health and air quality concerns directly related to the mold. Mold is generally treatable; however, you want to catch it in the early stages.

Most of these natural features are acceptable in timber frame applications and give a home a unique personality. Your timber frame architect will be able to explain these terms in relation to your timber frame design and outline your options in wood type, species, and grade.

Jeremy Bonin, AIA NCARB LEED AP
Bonin Architects & Associates, PLLC

Timber Frame Homes - Wood Types

When you’re planning to build a timber frame or post and beam home, there is another consideration in addition to the species of wood you will have.

Green: Green timbers are healthy living trees when harvested from the forest. They typically have a moisture content around 28 percent. The timbers dry for a year or longer after the timber frame is erected. Throughout the drying process the timbers will shrink in the direction perpendicular to the grain of the wood, check (typically small cracks perpendicular to the growth rings running with the grain of the wood) and possibly twisting as they acclimate to the temperature and humidity of the environment. These are characteristic of green lumber and unavoidable, but do not affect the structural integrity of the timber frame. Green timbers are the least expensive option.

Standing Dead: Standing Dead timbers are trees that have been killed by insect infestation, fire, or other means and are still standing in the forest. The timbers are individually selected and harvested and considered a more environmentally conscious choice. More expensive than green timbers, standing dead has a lower moisture content, making it more stable and less apt to twist or check.

Kiln or Air Dried: To hasten the drying process and reduce natural shrinking and checking, you can choose to have your timbers kiln dried or air dried. Timbers that are kiln dried are baked in huge kilns for several weeks. Air drying is done in a warehouse or log yard, where the timbers sit for several months, even years, to dry. Moisture is reduced to 18% to 20% in these processes.

Reclaimed: You could also choose reclaimed wood to build your timber frame or post and beam home. Reclaimed timbers are salvaged from dismantled factories, barns, and bridges. The moisture content is minimal, making them strong and solid. All have a rich history and story to tell, adding to the character of your home. Many have nail and worm holes which can be left exposed. Because of the labor involved in harvesting these timbers, they are one of the most expensive types of wood.

Glue-Laminated Timbers: Glue-laminated timbers are used to span great distances in a timber frame or post and beam home. They are also used in homes made solely of Structural Insulated Panels (also called SIPs or stress skin panels) to support the panels in longer spans. Full trees are brought to a mill, where the bark is removed and the trees are sawn into boards usually no thicker than two inches thick. The boards are then kiln dried for about a week until the moisture content is below 15%, usually around 8%-10% moisture. The boards are then planned smooth. The smooth planks then travel to a machine that applies one of two kinds of glue to the interior boards. One kind of glue reacts with radio frequency to cure the glue in a few minutes, and the other uses a high-pressure clamp which hold the boards together for 24 hours. After drying, the timber runs through a profiler to make sure it is perfectly straight and uniform. Glue-Laminated timbers are very strong and resource efficient, they typically cost more than green lumber but provide greater strength & uniformity.

With all of the options available, aesthetics and strength can be equally addressed and timber types can also be mixed (timber species as well). Consider these options early when building a green home. We can work with you to integrate them and even provide samples during the design process.

Jackie Lampiasi, Marketing Director

Bonin Architects & Associates, PLLC