At first glance, timber frames can look alike before installation on your foundation.  However, timbers can shrink, twist, check, and release sap.  That is why it is important during the design phase to discuss the pros and cons of different material standards with your timber frame builder.  The standards you set with them will affect the cost and how well the frame ages.  In some cases, it is significant as 30%.

In this blog post, we will envision a client that wants a traditional frame made from Douglas fir that has tight joinery and a clean finish.  In this scenario, our goal is to use stable timbers to limit changes in the wood and the joinery over time.  The material standards that will primary determine this client’s satisfaction will be the grade, cut, and moisture levels of their timbers.  Below are recommendations for them.

1.  Grade
You may have noticed from trips to the lumber store all wood is not created equal.  The quality of the grain (spiral or tightness), wane, knots, or checks varies between timbers.  We use the NLGA Grading Rules that ranks Douglas fir timbers from No. 2 Structural to Select Structural, to B clear and better.  The chart below shows a few differences between two grades on the face of a 12” Douglas fir post.

Recommendation: We recommend this timber frame home buyer purchase timbers that are Select Structural or better.  We have found it difficult to control results when the timbers are below these grades.

2.  Cut
Another consideration we make is whether or not to use free of heart (FOH) or boxed heart center timbers.  A boxed heart timber contains the center of the tree while a free-of-heart timber excludes the pith (soft center). Free of heart timbers check, warp, and twist less because the edge grain shrinks less than face grain on boxed heart.  The image below compares a boxed heart timber to a free of heart timber (not quarter sawn).  You can see how the checks (cracks) in the boxed heart are visible from the outside of the post.  The free of heart timber will show no visible signs of checking when stood upright.

Recommendation: Free of heart timbers are best suited for this situation.  Please note that companies sell different kinds of FOH products.  It is best to specify quarter sawn FOH.

3.    Moisture Content
Because it takes timbers 2-5 years to air dry, many people purchase “green” timber frames that are manufactured before the timbers stabilize.  An alternative is to kiln dry the wood before creating the joinery.  The benefits include:

• Wood will release sap until the moisture content drops below 20-25%.  Most kilns will decrease the moisture levels to or below this point.  As a result, the sap crystallizes inside the timbers instead of forming on the surface.
• Joinery remains tighter.
• The weight on the frame will remain as engineered.  As green frames dry, weight can be transferred from posts to the dowels holding up the beams or knee braces.  
• Because most of the checking has occurred, the worst cracks can be hidden during production.

There are different kinds of kiln drying technology.  For a tight fitting frame, we recommend timbers be radio frequency kiln dried rather than conventionally kilned.  Not only is the evaporation process less disruptive to the fibers, but the moisture level are lower and more consistent.  In the chart below, we compare the gapping that occurs years after installation between a knee brace and a Douglas fir post.

Recommendation: Since the envisioned client wants a more refined look, we would recommend drying the wood in a kiln before the frame is built.  The price for a radio frequency kiln dried frame will add approximately 20% to the entire contract.

Summary
It is possible for the price of a timber frame to fluctuate 30% based on your style and how gracefully you wish your frame to age.  In the case highlighted above, it is important the frame be made from free-of-heart, select structural timbers.  To reduce gapping and the appearance of sap, they should also radio frequency dry the frame before the manufacturing process.

Please contact us for more information or to discuss the construction of your future log or timber home.

Builders are not known for over communicating.  Too often, in a race to complete a project, I have seen communication break down between sub contractors.   At critical times, these mistakes can cost you money which must be financed or deducted from other amenities.  So as a future home owner, it’s important to expect your post and beam builder to coordinate closely with yourself or your general contractor to avoid any unnecessary expenses.

A Case Study
This spring, our company will be assembling a handcrafted post and beam house (see below) in British Columbia, Canada.  Totaling nearly 10,500 square feet (house and garage), this project requires forethought between our company, the general contractor, and the client.

The Initial Assessment
We are fortunate that the site is relatively flat and easily accessible by truck (towing a 48’ trailer).  There are no encumbrances such as power lines or trees to slow the movement of the crane.  Wisely, the client has hired a project manager and contractor with experience building log homes.  The experienced structural engineer also made reasonable fastening requirements.  Lastly, we can select a week with good weather because the site is nearby our office.

Areas of Focus
To increase the efficiency of the assembly, we are addressing these issues before assembly day.

FIND A PROFICIENT CRANE OPERATOR- We will join over 2,200 pieces of wood and metal to assemble this post & beam home.  The speed of the assembly will be impacted by the competency of the crane operator.  In our case, we are recommending a proven crane operator in our area.  If your log home builder can not recommend someone, be sure they help you interview candidates.  If the crane operator is slow, don’t be afraid to pull them off your job.  The goal is to keep the crane swinging all day long.  Over the course of our project, the wrong operator could easily add 3 more days to the assembly costing our client over $6,000.  Worse, the operator could jeopardize the safety of our crew.

ORGANIZE THE LOGS – To keep the crane moving, we have organized the logs in a specific manner.  We would recommend you review these ideas before you sign a contract with a post and beam builder.  In our case, every minute the crane sits costs our client $3.00.

1. Use lumber to separate each round of logs on the trailer so you can quickly strap the logs.
2. In addition to labeling each log, categorize them using colored tape (e.g. roof logs, garage pieces, main floor posts, floor joists, etc…) so someone unfamiliar with the project can sort them on the ground for future lifts.
3. Pre-assemble as many pieces as possible.  For example, we have assembled some of the roof pieces.
4. Bring plenty of lift-straps so you can be strapping logs while the others are moved to the building.
5. Station the crane where it can reach all sections of the building.  In our case, it is between the port corche and the garage.  This central location means we don’t need to move.

PLAN FOR THE FOUNDATION– There are 37 points in this house where the post and beam structure connects to the sub floor.  Each is a moment of truth between us and the contractor that if not correct, can add hours to the assembly.   Common problems at this stage include sloping or out-of-square foundations and poorly located anchor bolts or framing.  Our solution is a READY MADE sill system which allows us to quickly adjust to problems with the sub floor.  Rather than leveling one post at a time while the crane waits overhead, we will install it a day before the crane arrives – saving our client money.

We are also going to visit the site to ensure the foundation has been adequately backfilled so the construction team can move about the site quickly and safely.  If your log house builder is unable to visit the site, we recommend they go over the plans with your contractor or you before the foundation is poured.  Plus also review photos of it after the foundation is poured to anticipate any problems.

A Final Note
Before you sign a contract with your log home builder, ask them for a reassembly plan specific to your project.  Together, you can predict the likely problems.  They should also describe which responsibilities each of you assume during the reassembly.  Make sure the contract for the post & beam house specifies which non-wood components and tools are provided by them.  You want to make sure you have the necessary resources on site.

Remember that a fixed-contract price to build a post and beam building does not insulate you from new bills.  Pick a builder who is thoughtful and has already taken a team based approach before asking for your business.

If you decide to build a log cabin, you will need to estimate the cost to reassemble the log shell on your lot. Your two main expenses will be labor and a crane rental. Usually the cost of a crane per hour is between $150 and $2oo an hour. So the cost of the crane could be $7,000 for a 2,500 sq ft house over the course of 4 days. To keep costs down, its important to plan ahead in order to keep the crane swinging. One issue we consider is whether or not to insulate the log walls on-site or at our production yard. The answer is “it depends”.

If you have lots of room to off-load logs from the trucks or container, it is best to either insulate them on the ground at your lot or at a builders yard. You should negotiate with your log home builder where they will complete the work. If it is at your site, they are passing on some of the labor and crane costs to you.

P-gasket insulation being installed at our yard

In some cases it is necessary to insulated each log at a builders yard. Case in point, last year we  reassembled a Douglas fir log home for a client in Sunshine Valley, Canada. Because the foundation could not be backfilled on 3 sides, each log went straight from the trucks to the walls. If we insulated the logs with gasketing at our yard.  If we hadn’t the client would likely pay for an additional 20 hours of crane, truck, and labor time.