Author: Susan

Dai goes to the source

From Daizen News 1 March 2012

Part of an exchange Dai had with Max Closen, of My-Ti-Con Timber Connectors.

“Hi Max, at December’s CWC engineer workshop in Kelowna, I was surprised by your placing of anchor screws from the main posts. I would always insert screws from the floor beam side, like a spike, but your method makes more sense.

I believe others think as I do. Can you explain for my readers why it’s better to send the anchor screw in from the main post that receives the floor beam?”—Dai

Max says,

Here’s why. Fig. 1 below shows a typical joist-to-beam connection with ASSY structural wood screws installed at an angle. Installing screws on an angle uses their strongest property: withdrawal resistance.

Fig. 1. Insertion, at angles, of ASSY wood screws.

Commonly, screw-type fasteners are not driven into the wood on an angle but instead positioned perpendicular to a member’s surface. In perpendicular insertion, the weakest property of a screw-type fastener, its dowel action, is in force. A simple experiment can explain the difference.

Experiment:

1. Take a ¼ x 4-in. wood screw and drive half of its length into the wood. Now bend the screw over. Notice how easy it was to bend the screw.
2. Take a second screw and drive it into the wood under the same conditions. Now try to pull that screw out. As you saw, the screw didn’t want to come out from the wood. The same principle applies for the connection shown in Fig. 1, where the screw is driven in on an angle to the wood grain of the joist.

The two blue arrows in Fig. 1 indicate the correct direction for screw installation in order to maximize its capacity in this connection. The starting point of installation—whether from the top of the beam or the bottom of the joist—is up to the installer.

The red arrow indicates the least efficient installation direction. Installing the fastener as shown in red will not put the screw in tension and therefore will not use the screw’s high withdrawal resistance.

The range of the installation angle  between the wood grain of the joist member and the screw axis is typically  (Fig. 2). Here you see an application of the basic trigonometric functions we all learned in high school (a² + b² = c²).

Fig. 2.  Definition of angle  .

I caution against installing screws at angles smaller than 30°. As the angle decreases between the wood grain and the fastener axis, end grain application occurs and reduced capacities must be considered.—Max

ASSY structural wood screws are made in Germany by SWG Production, a  member of the  WURTH Group. Statements made here are to the best knowledge and understanding of the author and shall be confirmed by the structural engineer of record of the project. My-Ti-Con Timber Connectors Inc. and its owners assume no liability.

Timber accents: brackets

From Daizen News 1 March 2011

The new Daizen timber accents system is proving out very well. Our Timber Accents Design Guide has been much-requested and well-received.  Accents available include beam ends, brackets, and trusses. Here is a look at the brackets section of the guide.

For an idea of how to use it, here are a few excerpts from the Brackets section. The page above shows the four basic bracket designs available; once you choose the bracket, you then choose from a wide variety of sizes, and from five different beam ends.

To order a bracket, you simply specify (1) the bracket design, (2) the size you want (for your convenience, recommended sizes are included), and (3) the beam end type.  We do the rest.

What a great way to incorporate timber into your project with the least amount of extra work. For a PDF of the Daizen Timber Accents Guide, email [email protected].

Building wisdom 1 January 2012

From Daizen newsletter

Raise high the roof beam, carpenters.

—Sappho

Valdes lighthouse in Cottage magazine

From Daizen News, 1 January 2012

The designer Carl Willms, a frequent Daizen collaborator, worked with Daizen to build a lighthouse-style dwelling onto an existing cabin on remote Valdes Island. All of the timber was transported by boat, and it needed to be of manageable size for a hand-raising, since there was no way to get a crane or other heavy machinery to the island.

Not only can you read of this project in the Daizen portfolio; it’s also on the cover of the January–February 2012 issue of Cottage magazine.

A photo from the magazine: Carl Willms, standing, in the main room with his son Kyle, back left, and Kiyo Hagiwara, a friend and employee of Daizen.

The wood appointments in the cabin’s kitchen–the first floor of the lighthouse–were created by master carpenter Jim Willms.

The magazine article tells a slightly different story from the Daizen portfolio; both are interesting. To read the Cottage magazine article, download it here.