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Featured Post

Find the Best Timber Frame Companies

Ask someone who builds timber frames for a living what makes their company different, and you’re likely to hear some variation on the theme of high quality, responsive service, and talented people.  

Their answer may be truthful, but if you want to build a timber frame, you haven’t learned what you need to know to make an informed decision.  

So, how exactly do you do that?  Ask better questions, listen carefully, and interview like a pro.   

Here are some tips from newspaper reporters and the FBI about how to interview people (after all, they do this for a living):   

Just like building a timber frame, start with the foundation

Timber Frame Post Base Hardware

There may be no such thing as a stupid question, but some are a lot better than others.  It can be helpful to play “let’s pretend”.  So, pretend for a moment you have a superpower—any question you ask will be answered.  What questions would you like to know the answers to? 

As you develop your questions, start by asking yourself what you want to achieve.  For example, are you looking for a solution to a particular problem?  Are you looking to uncover something?  Are you looking for a better understanding?  Decided to build a timber frame, but trying to choose between 2 or 3 apparently equally qualified timber frame subcontractors?

Typically, you’ll want to uncover:

  1. Can they do the work?
  2. Will they do it when you want it done?
  3. Can they do it for the investment you’re willing to make?
  4. What would it be like to work with this firm?
  5. Is this timber frame company the best fit, or not?
  6. What could possibly go wrong?

Get comfortable asking questions

You have a right to ask questions—you’re about to write a big check.  Furthermore, you have a responsibility to ask questions—if you don’t ask the right questions and bad things happen, you have only yourself to blame.  

(Not everyone has to like what you ask.  You’re on safe ground as long as your intention and purpose for asking the question comes from a good place. ) 

Use your powers of observation

Building a Timber Frame Inspection

Use the part of your brain that has evolved over tens of thousands of years to sense and observe the environment.  Do people seem to like working there? Is the phone ringing?  Do the other employees avert their eyes when you pass? Notice cigarette butts or litter as you step out of your car? Is the place generally organized or not? Tension in the air?  Do you see anyone you would be uncomfortable with in your home?

Ask non-leading questions

A leading question implies its own answer and subtly prompts the respondent how to answer.  You’ll learn more if you try not to give clues about how you feel or think about something.

If you were to build a timber frame home, what wood would you choose?

            vs

Oak shrinks a lot, correct?

In general, ask open-ended questions

An open-ended question is one that can’t be answered yes or no or by a limited set of possible answers. They encourage the respondent to talk thereby providing you the opportunity to learn things you wouldn’t otherwise.

What are you most proud of about your company and why?  

            vs

What are your company’s strengths?

Some thoughtful questions

Timber Frame Questions

What are the challenges you see in our project?

If we ask for references from recently completed jobs, how would that process work?  

Are you a member of the Timber Framers Guild? (if so, why? If not, why not?)

I don’t suppose your firm is currently in litigation with anyone?

We have to stick to our budget. How do we know the timber frame won’t end up costing more?

Are the people who work here employees or subcontractors?

Are there any outstanding tax liens or judgments against the company, or the owner(s)?

Have you ever had an unhappy client?  If so, would you share what happened?

What’s your process for handling changes?

What’s not included in your price?

How often will the business owner check in on my project?

How do we resolve any disagreements?

May I see your certificates of general liability and workers comp insurance?

Who would be overseeing my project? May I meet her?

What’s the best thing that’s happened to your company this year?

Is your firm licensed to do business in my state?

How long have you been in business? According to the U.S. Bureau of Labor Statistics, about 20 percent of small businesses fail within their first year. By the end of their fifth year, roughly half of small businesses fail. After that, only about one in three small businesses get to the 10-year mark and live to tell the tale. After that, survival rates flatten out. Businesses fail in good times and bad, and to paraphrase Ernest Hemingway, it happens gradually, then suddenly.  Consider for a moment what would happen to the money you’d paid to date, were you in the middle of building a timber frame home and the timber frame manufacturer abruptly ceased operations and stopped returning your calls.

Filed Under: Blog, Featured Post, What's New

Timber Frame Trusses

truss, n. A collection of timbers or members forming one of the principal supports, as of a roof or bridge, and framed together so as to give mutual support and prevent distortion, as by the forces of gravity and wind loads.

Trusses, whether structural or decorative, are usually named in one of five ways: 1. from the construction in which they are used; as in, roof truss or bridge truss, etc.;  2. from their form; as in, lenticular truss, etc.; 3. from their resemblance to certain objects; as in, scissors truss, etc.; 4. from some prominent feature in their construction; as in, king post truss, hammer beam truss, etc.; 5. from the person by whom they were in invented; as in, Howe truss, etc. (adapted from the Funk & Wagnalls Company 1943 Standard Dictionary of the English Language)

Timber Truss Types

Timber Frame King Post Truss

King Post Truss

The king post truss with struts is popular, timeless, very strong, and an elegantly simple truss design. This style can be embellished with radius cuts on the struts and a through tenon at the base of the king post (as pictured above). This truss is very adaptable with regard to desired span and roof pitch.

Timber Frame King Post Truss Struts Queen Posts

King Post Truss With Struts and Queen Posts

The king post truss with struts & queen posts is based on the popular king post truss design, but with the addition of two queen posts (pictured above). This timber truss is also very strong, and adaptable with regard to desired span and roof pitch. This arrangement is particularly good for longer timber frame truss spans (in excess of 24’ feet).

Heavy Timber Frame King Post Truss

King Post Truss With Extra Bolsters

The king post truss with extra bolsters builds on a favorite timber truss design with two added bolsters on the underside of the bottom horizontal chord for a heftier look. These mirror image pieces added to the underside of the bottom chord can provide a stepped transition to the vertical wall plane. The bolsters can have a wide variety of decorative profiles cut into their visible ends. Twin metal straps can also be banded around both the bolster and the bottom chord for a craftsman detail.

Timber Frame Truss curved arched lower chord

Arch Chord King Post Truss

An arch chord king post truss is another variation on the classic king post style, this time with an arched lower chord. This design adds a curvilinear element into the ceiling space instead of the standard horizontal timber, raising the structure somewhat and giving some extra volume below. Some of our clients have pointed out how the curves in this timber frame truss soften the lines and convey a natural aesthetic (after all, there are very few straight lines in nature). The radius cut for the arch should be shallow in order to be cut out of solid sawn timber. However, more semi-circular arches can be accommodated by using a grain matched glue laminated arch material (this is considerably more expensive than solid sawn timber).

Queen Post Timber Frame Truss with arched curved lower chord

Arch Chord With Queen Posts Timber Frame Truss

The arch chord with queen posts timber frame truss is another variation on the classic king post style, this time with twin vertical queen posts. This design adds more vertical elements above the arched bottom chord with the extra volume below. The radius cut for the arch should be shallow in order to be cut out of solid sawn timber. We like to use a spline tenon to joint the 2 half arches to the base of the king post. On larger spans, this configuration often requires concealed steel connectors to resist tension and spreading along the arch itself.

Timber Frame Scissors Truss

Scissors Truss

A scissors truss is a traditional truss style with many variations, this design can be used in small or large spans. Scissors trusses are not recommended for shallow roof pitches ( below 8/12 pitch ). We like to add the queen posts on either side of the central king posts. These trusses have a more complicated geometry with many angled intersections and a higher center for added space.

Hammer Beam Timber Frame Truss

Hammer Beam Timber Frame Truss

A hammer beam timber frame truss is based on the more elaborate hammer beam timber frame bent design. The combination of heavy timber and metal tie rods and turnbuckle is not only appealing but is often required to handle the spreading forces this configuration will develop. In case you were wondering, a hammer beam is a short beam projecting laterally from the inside of a wall, and serving as a tie beam.

Hammer Beam Timber Frame Truss Bent and Wall Posts

Hammer Beam Timber Frame Bent

A hammer beam timber frame bent, pictured above, is a beautiful and more complicated design, and creates dramatic vaulted spaces. There are many ways to embellish this design, from through tenons and radius cuts to decorative pendants or finials. The hammer beam bent is often associated with religious structures, great halls, or great rooms. Without a metal tie rod and turnbuckle, deep wall posts and/or concealed steel connectors are needed to handle the forces this configuration will develop.

Timber frame trusses with purlins

Timber Frame Truss and Purlins

Timber frame truss and purlins: adding purlins between heavy timber trusses is an elegant way to reduce the cost of a timber frame roof because purlins permit an increased on-center distance between trusses (so you purchase fewer trusses). An added benefit are the strong lines that purlins create by running parallel to the ridge beam(s). (Another benefit is that purlins are a great place for placing LED lighting fixtures). Purlins often sit in pockets cut into the truss rafters (as shown) but can also sit on top of the truss rafter to create a secondary layer to the roof structure. There are some span restrictions based on the purlin size ( beam width  x depth) and how close they are together. This is a very traditional concept in heavy timber roof framing. (purlins are a series of horizontal timbers laid across (or connected to, as depicted above), the principal rafters, and support the roof covering–typically 2×6 tongue and groove boards, conventional or structural insulated panels (SIPs), and roofing)

Timber Frame truss roof with ridge beam and rafters

Timber Frame Truss Roof With Ridge Beams and Common Rafters

A timber frame truss roof with ridge beams and common rafters can provide a larger space between each truss. We like common rafters between each truss thereby giving a rhythm to the roof structure. The common rafters are often smaller than the truss timbers to differentiate between the primary and secondary timber frame elements.

Timber Frame Truss Roof With Ridge Beam, Purlins, and Common Rafters

A timber frame truss roof with ridge beam, purlins, and common rafters is a stunning combination that creates visual interest and structural complexity. There is a hierarchy of timber framing at work here, with trusses supporting the ridge and purlin beams. Above these components is a rack of common rafters. Typically the trusses are made from the biggest timbers, followed by intermediate sized ridge and purlins followed by the common rafters as the smallest timbers. One of our favorite combinations!

Timber Howe Truss
Warren Timber Truss
Queen Post Parallel Chord Truss

Bridge Trusses

The Howe, Warren, and Queen Post Parallel Chord Trusses, sometimes referred to as Bridge Trusses are relatively simple designs used in the construction of everything from the earliest 19th century modern bridges to WW II aircraft hangars. They’re efficient, strong, and characterized by the joining of numerous smaller members into a series of interconnected triangles. In addition to being a proven way to solve the engineering problem of long spans, we think they look great in modern timber framing (see an example here) and are one of the best examples of form following function.

Cruck Frame Bent

Cruck Frames, found primarily in the UK, were the original A-frame. According to Cruck Building: A Survey, the definitive definition of a cruck is as follows: “a true cruck consists of a pair of timbers (blades), straight or curved, serving as the principals of a roof, and stretching to point at or close to the apex of the roof, from a level well down the side walls.”

Copyright 2019 Carolina Timberworks. All rights reserved. Illustrations by Eric Lubsen.

Timber Frame Trusses Inquiry

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Filed Under: Blog, FAQs, Featured Post, What's New Tagged With: heavy timber roof, timber frame roof, timber frame trusses

Why Do Timbers Split and Crack?

Eric Morley on why timbers split and crack, how long it takes timber to dry, where to get dry timbers, and why gunshots in the night are nothing to be afraid of when you understand wood checking and splitting.

What Causes Wood to Crack?

The Short Answer: Wood Checking

Splits and cracks (known as wood checks in the industry) occur when wood shrinks as it dries. Wood shrinks roughly twice as much along with the growth rings (radially) as it does across the rings (tangentially). It is this uneven shrinkage that causes checks to develop.

Douglas Fir Timber Checks cracks splits

Is Wood Checking Bad?

Here at Carolina Timberworks, we think of them as wrinkles in a cotton shirt. It proves the timber is real. Checks are what make a solid timber look different from a boxed beam. Look at the reclaimed timber below. It is impossible to predict where a check will appear in timber. It is the check that gives this reclaimed Oak timber so much of its character and a big part of what makes it completely unique and different from any other beam in the world.

Timber cracks (checks) in Reclaimed Wood Timber

Ever Heard the Song of the Wood?

Have you ever taken a hot loaf of artisan bread out of the oven, and put your ear to it? If you do, you’ll hear the song of the bread–pops and crackles as the crust shrinks, cracks, and dries.

Walk into a timber framer’s shop one winter evening when everyone has gone home for the day. Throw another log into the woodstove, and listen carefully. If there are green (wet) timbers arrayed on sawhorses, within a few minutes, you’re likely to hear the song of the wood – a symphony of pops and cracks as wood checking occurs.

If one night, asleep in your new home, you’re awoken by a loud crack a little like a gunshot. Don’t worry.  Roll over and go back to sleep. It’s just your timbers singing to you. That’s wood checking in action.

cedar hammer beam truss on sawhorses

Why Does Wood Shrink? Why Wood Cracks

It sometimes surprises people to learn that roughly half of a living tree’s weight is water. Let’s consider a 24’ long Douglas Fir log that measures 34” diameter at the large end and 14” at the small end as an example. This hypothetical green (wet) log would contain a little over 1 ton of water or about five 55 gallon drums of water.

Sometimes when we drive a chisel into green (wet) timber, water spurts out of the wood. Wood is hydroscopic – meaning it’s like a sponge in that it can absorb, hold and release water. When freshly cut, approximately half of a tree’s weight is water. The photograph below shows water in a freshly cut Cypress timber–and how the timber is drying from the outside in.

Water in Cypress Beam

How Long Does It Take a Timber to Dry?

It’s not exactly a fast process. It depends on the humidity of the environment in which the timber is located, but one rule of thumb is that timber air dries about one inch per year.  Thus a 12” x 12” timber would take about six years to dry to the center.

How Dry Will the Timber Become?

A timber will eventually air dry to the Equilibrium Moisture Content (EMC) of its environment.  The EMC is the point at which wood is neither losing nor absorbing water.  A timber’s moisture content is determined by the atmospheric humidity of the timber’s environment.

That environment varies, of course.  Is the timber located inside, or outside?  What part of the country is it located in? What time of year is it? For example, in the dry mountain air of Denver, the outdoor EMC of wood exposed to the outdoor atmosphere in July is 9.4%, while New Orleans is 15.3% (Forest Products Laboratory:  Equilibrium Moisture Content of Wood in Outdoor Locations in the United States and Worldwide, August 1988).

How Wet (or Dry) Are My Timbers?

Since we can’t see the water in the wood, moisture meters are used to measure moisture content. Inexpensive moisture meters measure the surface moisture content which works ok for 3/4” boards, but not 8” thick timbers. Professional moisture meters use electromagnetic scanning to read the moisture in the wood, not on the surface of the beam.

wagner moisture meter measuring oak timber

What is the Average Moisture Content in the U.S.?

The majority of the U.S. has an 8% average moisture content, the Southeast and California coastal areas have an 11% average moisture content, and the Southwest desert areas are closer to 6%.

Most Timber Frames Are Built From Green (Wet) Wood

It is impractical (it takes years) to air dry timber, and we humans are an impatient species, so for the last two thousand years, people have been building timber frames from green (wet) timber. Yes, green timber will shrink, check, and sometimes twist as it dries, but timber framers and engineers understand and account for the movement. Checks begin on the exterior surface of the timber and almost always stop at the heart (center) of the timber, and are almost never a structural concern.

By the way, if a crack were to develop all the way through a timber (splitting it into two separate pieces), it would be called a split and might be cause for concern.

Learn more about timber framing all the ways timber can be used here.

white pine timber with split or woodchecking

How Much Does Green (Wet) Timber Shrink as It Dries?

Shrinkage depends on the species, but more than you may think!

Since many timber frames are built from Douglas Fir, let’s start by looking at a 12×12 Douglas Fir (Coastal) timber. This particular green (wet) Douglas Fir timber, dried to a final moisture content of 8%, would be expected to shrink a little less than 9/16” on each face from 12” x 12” to a final size of 11-7/16” x 11-7/16”.

Western Red Cedar shrinks less:  The same size timber in Western Red Cedar timber would shrink a bit less about 5/16” to 11-11/16” x 11-11/16”. Finally, how about a species with a high shrinkage rate, like White Oak? It would be expected to shrink a bit less than 3/4” to slightly larger than 11-1/4” x 11-1/4”.

6 Ways to Minimize Problems with a Green (Wet) Wood in a Timber Frame:

  1. Specify Free-Of-Heart-Center instead of the less expensive Boxed Heart grade.
  2. Apply a wax-based end sealer to the end grain to slow the drying process. We use Anchorseal, available at https://uccoatings.com/products/anchorseal/.
  3. Utilize housed joinery wherever possible.
  4. Drawbore pegged joints.
  5. The slower the wood cracking when drying, and the more gradual the process, the better (i.e., the worst thing you can do is enclose the timber frame and immediately turn on the heat or air conditioning full blast.)
  6. Do not apply a film-forming finish (i.e., polyurethane) to the greenwood.

I Don’t Want Wood Checking or Cracks in My Timbers. What Are My Options?

Don’t build with solid timber. Instead, ask us to price glulam beams for the timber frame, or to fabricate box beams from well-dried new or reclaimed lumber.

If you’re ok with some checks, but would prefer to avoid some of the characteristics of green lumber, consider purchasing your timber like you do your high-quality organic cotton t-shirts–pre-shrunk. There are two ways to buy dry beams: new timber that’s been dried in a kiln, or reclaimed wood that’s dried slowly and naturally for 50 or 100 years during its previous life as a barn or warehouse.

Where to Buy Kiln Dried Timbers?

We offer two types of kiln-dried timber:  Conventionally kiln-dried (KD), and Radio Frequency Kiln Dried (RFKD).  Conventional kiln drying dries about the outer 1” or so leaving most of the timber wet. The other method, RFKD, is similar to a giant microwave and dries timber to the core.

What you need to know about RFKD timber is that it currently works only on Douglas Fir, it is dry to the core, and it is more expensive. It is, however, not as dry as conventionally kiln-dried hardwood flooring or lumber (6-8% moisture content). For example the driest grade of RFKD timber measures 15% or less moisture content 3” in from the surface of the timber.

What About Using Reclaimed Wood in Timber Frame Construction?

Reclaimed wood beams that have naturally air-dried for 50-100 years during their previous life as a barn, factory, or warehouse are often completely dry to the core and the driest timbers available anywhere. It’s not easy to hand-scribe and connects irregular, twisted, and non-square reclaimed beams so the finished timber frame appears to have always been one frame.

We think a timber frame built from reclaimed wood is everything that today’s sleek, mass-produced, technology-saturated culture isn’t. It celebrates the cracks and character and dirt and all the other marks that time, weather, and use leave behind.

Reclaimed Wood timber frame great room highlands nc

Interested in learning more about timber framing? Check out our

Filed Under: Blog, FAQs, Featured Post, What's New Tagged With: Design, Engineering, Timber Frame 101, Timber Frame Construction

Is Timber Framing Sustainable?

Timber framing often uses less wood and resources, making it the most sustainable way of building out there.

Timber framing is one of the best ways to conserve our resources because post and beam homes are special places that people love, and because they are loved, they are maintained over the years, and because of that care, post and beam homes last for centuries rather than decades. Buildings that are loved get maintained, and well-maintained buildings last far longer.

Why is Timber Framing Sustainable?

  • Wood is one of our only renewable resources. Think about this sometimes overlooked and obvious fact.
  • Timber is a natural product. It is recyclable, biodegradable, and renewable. It does not off-gas toxins because there are none.

Timber, unlike 2×4 and 2×6 lumber, upon the end of the useful life of the timber frame or post and beam home, will be carefully dismantled and reused. Used 2x4s may one day be reused, but today are going into landfills, rotting, and releasing their stored carbon into the atmosphere.

Wood is a carbon sink. If kept dry, wood lasts indefinitely. If you leave a tree in the forest to die a natural death, it will rot and release its stored carbon. If you cut down a tree at the end of its natural life, it has spent years storing carbon and producing oxygen. If you then fabricate it into a timber frame, and keep it dry for centuries, the post and beam home is acting as a long-term carbon storage unit.

Post and beam homes can, and often do, use less wood than stick-built homes. post and beam homesThe figure we’ve heard is around 30% less. There are some caveats here, and it may seem counter-intuitive at first, but take a look at the photo (at left)  from Stewart Elliot of Riverbend Timber framing.

Timber frame homes use big timbers which come from big trees. Here’s another counter-intuitive one. Big timbers come from big trees–sometimes old-growth trees. Big trees have spent many, many years storing carbon and producing oxygen. Today’s 2x4s are manufactured from young, small trees – trees that have not lived long enough to store much carbon or to have produced much oxygen.

What we’re doing to make 2x4s cheaply is to grow genetically-engineered super fast-growing trees, cutting them down in 10 years, and then replanting. By the way, when we replant these crop trees, we’re not doing it by hand. We’re burning diesel fuel.  Is it a cheaper way to produce a 2×4?  Undoubtedly.  Is it greener wood?  We’re not so sure.

Timber frames or post and beam homes are the best use of old trees. In our view, it is far greener to cut down a majestic old-growth Douglas Fir tree at the end of its life, and fabricate it into a functional and gorgeous timber frame that will be treasured and maintained for centuries, than to cut it down and saw it into 2x4s that will eventually go into a landfill and rot, or produce window sashes which will rot, or make paper. Better to revere these fantastic trees by turning them into an architectural solution to a structural problem that is so stunning and useful that generations of people will benefit from, and take care of the building.

Some post and beam homes are built without cutting down a single tree by using reclaimed wood and beams from old buildings and factories. Adaptive reuse is growing in popularity across the timber frame and construction industries.

Is timber framing suistanable, like in this great room?
A working cattle farm on the New River, rich in flora and fauna…a marriage of modern amenities cloaked in old reclaimed wood…while inside fine art and fine craft engage in dialogue and soliloquy.

Nearby is a photograph of one of our timber homes that utilized reclaimed wood. We love putting old wood back to work, and the timber in this project is structural and is holding up the roof.

Timber framing is a darker shade of green. Having spent a week in a photovoltaic solar class, we’d note that no building material or technology is without consequences to the environment–not even solar panels. We contend that timber frame and post and beam homes, while not an environmentally perfect building solution, are demonstrably and quantifiably greener than most other conventional building methods.

Is there progress to be made? Sure! Yet, even so, timber framing, teamed with structural insulated panels and solar photovoltaic panels, is the most beautiful, green, and energy-efficient method of building we know of.

Filed Under: Blog, Featured Post, Timber Framing, What's New Tagged With: Design, Sustainability, Timber Frame Construction

© 2022 Carolina Timberworks. 210 Industrial Park Way, West Jefferson, NC 28694 T: 1-828-266-9663