How important is a gasket?

How important is a gasket?

  |   Newsletter, Techniques

From Daizen News, March 2013

The photo below shows a thermal image from a blow door test, superimposed over a shot of the house itself. A blow door test forces air through the house to determine where heat is escaping. The tongue-and-groove decking and, especially, one triangle

along the roof are areas of air leakage. Since they are in the upper part of the house, the heat loss is tremendous.

The air-tight joints with gaskets that we use prove that our joinery is not causing the heat loss. In one spot, where a beam intersects the roof plate via a wood housing, we thought a gasket was not needed. But the photo shows a distinct air leak. What we learned from this test result will change our frame joint details immediately; and with this knowledge, the leak was easy to fix.

More on an air-tight joint.

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A timber frame’s effect on the environment

  |   Newsletter

from Daizen News,  March 2014

It’s been a focus for us to understand clearly how our timber frame building operation impacts the environment. Naturally, cutting trees seems like damaging the environment, but a B.C. Log and Timber Building Industry lifecycle assessment (PDF) shows that a timber frame can be environmental friendly if built right.

The key is to build a structure that will last a long time. Doing this captures (or sequesters) a significant amount of carbon in the timber.

Once a tree reaches, say, 100 years in age, it is close to the maximum amount of carbon it can hold.

Two interesting things from this report:

  1. a cut tree will not capture any additional carbon, so, past that point, it is not improving the air; and
  2. in British Columbia, natural disasters like fire and insect infestation cause much more damage than harvesting by humans.

Sources of forest disturbance in Canada.

This tells us that, if we harvest trees arefully and, in that harvested area, continue to plant and grow trees, then harvesting a tree is not damaging the environment. Using the wood to build a long-lasting frame is a positive action, because it “saves” the carbon in the wood from being released into the atmosphere.

After the tree is harvested, how it’s processed is significant. A short-distance haul (and minimal use of fossil fuel for production) is the next factor to consider. Daizen uses mostly hydropower, with its computer-controlled minimum-input to maximum-output ratio.

Finally, the stain product used affects the environment the most in our operations.

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A traditional Japanese frame blessing

  |   Community, Newsletter

From Daizen News November 2011

A frame-blessing ceremony is no longer common, but we had a good opportunity to do one recently in Kamloops. The client requested the ceremony, gathering family and friends together. The purpose of the ceremony is to show the last piece of the frame fitting into the house while the people who will live in the house look on. That last timber assembly included a wetting bush (small pine tree) and a Canadian flag.

Flying in the last roof truss, adorned with a Canadian flag and the traditional wetting bush. The truss end is padded against the lifting strap.

Fitting the final assembly into place.

The client contributed wine and snacks for everyone who gathered to celebrate the fine frame that was built. They greatly admired the work of the designer, the contractor, and we timber framers. In this event I witnessed the client’s thoughtfulness.

I explained the process of creating a frame—trees in coastal BC, cut selectively, delivered to a specialty mill, and carefully kiln dried. Once the wood arrived at our workshop, we planed, sanded, stained, and fabricated the timbers. All were local operations employng local people. I have no doubt that they cared for the work and tried the best they could, each in their own specialty. I shared my pride and appreciation on behalf of all these teams.

I realized something important in this event. The cost of living is so high now, and supporting local businesses (as opposed to using big-box chains) can cause higher immediate costs. Those who allow us to team up with other local businesses who do good work are really supporting our society.

I then blessed the house in the traditional Japanese style. Salt, sake, and rice were prepared for the ceremony. We also created a piece of wood listing all teams and the raising date on its back, and a wish and celebration on the front.

On the red cloth are small bowls of salt, sake, and rice. Leaning vertically above it is the “blessing board.”

I began by spreading salt at each corner: east, south, west, and north. Then, all together, we made two bows, two taps of the wood, and one bow. I explained this as follows: “We are asking this piece of wood to protect anyone who lives under this frame for ten generations to come. While we bow and tap, please put all of your wishes for protection into to this piece of wood. Once the ceremony is completed, this board will stay inside the roof.”

After the bowing and tapping was done, the home’s new owners spread the sake in the same manner as I had done with the salt. The general contractor followed suit with the rice. Everyone thoroughly enjoyed the ceremony.

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A chance to learn from B. Allan Mackie

  |   Community, Newsletter

B. Allan Mackie founded a legendary log-building school—the first in the world, the B. Allan Mackie School of Log Building—in 1971, in Prince George, BC. He was almost 50 years old at that time.  Dai was an instructor and then a host of this school for 15 years; he has been the only director of the school other than Allan Mackie.

Allan just celebrated his 87th birthday on October 16th, and plans are in the works for a school “family reunion” in Japan.

Unfortunately, the school is no longer offering courses. For the last five years, Allan and Dai have focused on creating a nine-unit DVD training series, following B. Allan Mackie’s pioneering building philosophy, for those who want to build their own log homes. These are now available online (www.loghomedvd.com). The first 60-minute unit, introducing log building, is a free download.

From Daizen News November 2012

At this time, Allan is planning to attend the International Log Builders’ Association’s annual general meeting in Prescott, Arizona.

If you have an interest in log building, you will thoroughly enjoy this look at Mackie’s work, which has graced Canada and countries all over the world.

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Spotlight on comb finish

  |   Materials, Newsletter, Uncategorized

From Daizen News October 2012

Wood offers lots of options. One of the most important to homeowners—because it concerns the entire timber surface that you see (and live with) in the finished house—is the finish. If you want a rustic feel to your timber but don’t like fuzzy fibers that catch dust and provide an easy path for spiders, a comb finish may be the answer for you. In most cases, vertical grain is the favored grain look, but in a comb finish, flat grain is also pleasing to look at it.

To achieve a comb finish, we scrub a nylon brush along the grain that digs into, and compresses, the softer fibers. This makes the tight-grained winter growth stand out in relief. Running your hand over it feels good—you get to feel the grain, not just see it.

A comb finish also stands out more when stained.

It’s more work for us, which means a bit more cost, but the result is stunning. Most people who see it (and feel it) really love it.

For more, see our article, “Wood Texture,” on our website’s Downloads page.

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Epoxy post anchor system: the best so far

  |   Materials, Newsletter

From Daizen News October 2012

We work on many projects, so we receive lots of connection specs from many engineers. It seems like the post anchor connection is still a grey zone in terms of best practices.

This year, we’ve used epoxy anchor connections for almost all of our frames. Why? I think it’s because epoxy anchors lived up to all we thought they would be in their reasonable cost, ease of use, and reliability.

In most steel plate connections, the plates need to be embedded. Plates designed to be attached after the raising still need to be specially fabricated. We often get a phone call after the contractor has installed the frame: “Can you send me detailed information on the connections?” Strangely, we expect to get this information from the contractor! Clearly, there is clearly no generally-accepted standard connection for post anchors, so we have decided to provide a solution for it.

To see this YouTube video of the epoxy connection being assembled, click the image or this link—epoxy video.

When we see the new-building details for post anchors specified with expensive knife plates, we know it means lots of work to set them in place and prepare the timber slot for the plate, which in turn means much greater cost and lots of communication. If we knew who designed this, we could send them information in advance about what we’ve found works better. The epoxy system we favor is much easier to handle.

I explain it to engineers like this. “The epoxy connection is just like a threaded rod cured with epoxy in concrete and wood, except the engineer doesn’t need to worry about whether epoxy will fill properly, because our preferred system is designed to do that.”

Epoxy is injected into threaded rods.

The cavity fills from the middle.

I instruct the job supervisor as follows: “On the concrete that will support the post, find the spot that will be the center of each post, and drill a 6-in.-deep hole there, making sure no rebar is placed in that area. We will provide the rods. Please make sure to insert them with the injection nose accessible for filling the epoxy in once the frame is built.

“Regular concrete epoxy starts to cure in about 5 minutes, so each post needs to be stabilized in its final position for this time. With our system, you don’t need to hold each post in a definite position for 5 minutes. It allows the entire frame to be raised first. You can adjust the post locations, plumb them, and then inject the epoxy, which will set in place.

“The threaded rod is hollow; the injection nozzle plugs into it halfway down its length. The epoxy will flow out from the end of the rod, so when we see any excess from the injection hole, we know the entire space is filled.”

Setup for injecting the epoxy.  Note the small hole at the bottom of the timber.

The epoxy is injected into the hole. When epoxy oozes out, the cavity is full.

To summarize, here are the advantages of this system.

  • It requires no steel fabrication.

    It does not require any preparation in the concrete, except to make sure the center of the post location is rebar-free.

    The epoxy doesn’t need to be filled while building is happening; you inject the epoxy once all adjustments are complete and you’re ready to secure the post.

There is no distributor in North America for this epoxy system, so we carry the stock. For further details, please email us.

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An Air-Tight Joint

  |   Joinery, Materials, Newsletter

From Daizen News, September 2012

We see two different types of timber frame. One is a frame covered with Structural Insulated Panels (SIP) for high energy efficiency: a highly insulated, air-tight house system.

The other has an infill wall system where the frame is visible both inside and outside. In the infill wall frame, we use full-size tenons so the air cannot penetrate, but we also started using a gasket that is slotted into the joinery and then fills at the frame raising. The HannoWerk seal from Germany is a closed cell seal that expands to block any air or water that might run into the space.

Since we use a seal, the tenon does not need to be full size. We couldn’t achieve this effect with a bead of caulking because timber can shrink and, if a gap occurs, the caulk doesn’t have the ability to expand. Here you can see a groove just to the left of the tenon, where the seal will sit.

The seal in its groove. The groove is necessary so that the seal is seated and is not crushed as it expands.

The groove, with seal, is outside of the joinery. Most likely, the seal will be hidden by a framed infill wall.

Seal arrives to us compressed in a roll that will expand to almost 10 times its original size, to ensure that the gap is sealed.

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