Thread: A Japanese timber framed garden shed

Two full days of work, mostly by a neighbor and friends since I'm a bit too old to be a roof monkey. But I was a champion go-fer and in a few sticky cases the decider. Ceiling boards are done.

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Originally Posted by GRadice

And the joinery for those perimeter frames where they meet at the ridge. The frames sit on, overlap a bit, and are screwed to the barge boards that I've already shown. According to the Japanese carpentry text I'm using as a guide the barge end frames have this odd joint which is not fixed by any wedges or pins but seems to mainly be used to align and register the frames on the two sides of the gable.

One thing I love about this text is that even though the text is in Japanese, which I can't read, the drawing are clear and measurements are proportional.

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And one set of my attempts.

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So, is 1 Shaku close enough to 1 foot for the carpentry work you are doing?
Or 1 Bu close enough to 1/8" for the joinery you are using?

It looks like the Japanese units of length are just about the same as the imperial system, but in decimal increments !?!?!!

Thanks for showing us the details of the various joints you are using in the process of building your "shed". Always interesting trying to work out how they actually "lock"!

Cheers
Yvan

You are correct that the shaku is close to an English foot, (1 shaku = 0.99409 ft) but divided into decimals. Not close enough to be interchangeable if you mean marking a mortise in shaku and its tenon in English. In my situation, I need to stick with English for the roof parts because my roofing materials are produced in feet/inches. But yes, overall this shed built with the shaku system would not be noticeably different in size from what I'vce done. I am using metric for all of the rest of the shed parts which has meant lots of conversions from English to metric and back.

As I mentioned, the Japanese joinery text that I like uses proportions. So a mortise will be 1/4 the width of the post it is in, for example. Or a tongue will be 1/3 the thickness of its board.

And I've installed two of the gable end lattices. I hope to get the other two installed tomorrow. I still need to add their trim pieces on the outside and eventually demountable screens inside to keep the bugs out.

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And the other two lattices today. I still need to add some small trim pieces but now, except for the roof cladding yet to come, you can see how the whole gable end will look.

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This end faces west. At sundown the low angle light makes it through the lattice. I was hoping it would look something like this, and it does!

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This is an experiment. I'm not a carpenter and I'm working for myself so I'm allowed to do weird stuff.

I want to attach some trim pieces to contain the gable lattices but I don't want to use metal screws or nails. One reason is esthetic. I'm not painting or caulking and I don't want screw or nail heads showing. I also really don't want the metal corrosion staining the wood. The other reason is that metal cools faster than wood and is a point of condensation in humid weather, which leads to rot. In old buildings often the degrade starts at nail holes for that reason. Or so I've been told. But the trim pieces are too small for wood joinery.

I'm trying bamboo nails.

I bought a package of 150 mm x 4 mm bamboo barbeque kebab skewers. I cut them into ~ 35 mm lengths. I cut off the tip of the skewers and used a pencil sharpener to taper the ends of the other pieces.

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Alas, I don't have metric drill bits. I found that decent substitutes are 5/32" or 9/64" Imperial bits. Drill and then tap in the nail. I chose to pare them flush. They are barely visible but not garish.

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There are some odd flag shaped trim bits where the rafters meet the middle of the eave beams. Those got a single bamboo nail.

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I have no idea how well this will work over time. But I reckon the stakes are low. If the pieces work loose with seasonal expansion and contraction, I or a future owner can probably shoot some metal nails in from the non-visible back side and set it right.

your on a winner with that one

The past week or so was unusually clear and dry for November here so I was able to remove the tarp and get the roof planks installed with some much needed help from a neighbor. I've never been comfortable with heights and especially now at 71, I admit to being shaky on a ladder and a roof. But we got it done and no one got hurt.

Here is a view from my kitchen window at the start of planking on rare sunny morning. We screwed the planks rather than nailing them. That took longer.

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And over the few days it took to finish the job I came across this news feature from Japan:

Repair workers turn up 400-yr-old chisel found left under roof of Kyoto temple - The Mainichi


Which gave me an idea. And yes, I did.

A friend who was at the frame raising in July sent me his collection of short video clips he took. I made a rough movie of them. The real time sights and sounds give a pretty good impression of how the day went starting with assembling the first bent and finishing with me tacking up the laurel bough on the ridge.

I've always wanted to direct...

https://www.youtube.com/watch?v=4qd50X1v9k0&feature=youtu.be

I finished and installed the kamoi for the doors and window. I described making these and how they work a few months (!) ago and now finally got a chance to see them in place. To refresh, a kamoi is a combined header, upper jamb, and door/window track. In typical "stick built" construction in the USA these would be three separate pieces with the header a permanent part of the framing. In this old school Japanese construction it is one piece and added after the frame is assembled. That complicates installation since it has to fit precisely between posts, level and square to prevent the sliding doors or windows binding, and give a finished look without applied trim or caulk or paint. Don't try this at home! I got it level and square but I'll admit to some gaps where the kamoi meet the posts. That was because the post surfaces were not exactly square to each other and I didn't think to try to scribe the kamoi. Oh, well. Next time I'll do better.

The door and window kamoi are in red.

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And what they look like from the inside, installed. You can see from underneath a groove for the inside door and window. The groove for the outside door and window will be in a separate jamb applied to the face of the shed.


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To get a tight fit between the posts, the preferred method is to cut the kamoi a fraction of a millimeter too long, and then temporarily spread the posts apart somehow. A post with an adjustable, screwed base can be adapted. I used some clamps/cramps that are reversible for spreading rather than drawing together. It worked. Not the best picture, sorry. But you can see the mortises for the sliding tenons.

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And here is one of the clever sliding, dovetailed tenons after tapping it into its corresponding mortice in the post. I sweated laying out and making those mortices on the already raised posts. Only one chance to get that location and dimensions right, and I think I did.


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I had worried about this part of the build for months. I treated myself to a nice single malt afterwards.

All good results deserve a good single malt

I'm not an aficiando but do treat myself to one bottle to last the dark, cold rainy season here that has just started. Last year it was an Ardbeg Uigedail. I liked that very much. This year its price jumped considerably. I'm on the Ardbeg 10 year now. I don't like it as much, but it is better than no single malt!

Originally Posted by GRadice

A friend who was at the frame raising in July sent me his collection of short video clips he took. I made a rough movie of them. The real time sights and sounds give a pretty good impression of how the day went starting with assembling the first bent and finishing with me tacking up the laurel bough on the ridge.

I've always wanted to direct...

https://www.youtube.com/watch?v=4qd50X1v9k0&feature=youtu.be

Yet another proof that force should never, never be used...only bigger mallets !!!

This garden shed ain't goin' nowhere!

Cheers,
Yvan

I'm on to the window and door jambs. I'm using a design that from what I understand is not common in Japan. But my guru here in the USA likes it and used it on his own home, and that is good enough for me. The idea is that you place the jambs outside of the frame so that the weather doesn't attack the important frame components but rather the smaller and sacrificial/replaceable jamb parts. The scheme also adds a layer of architectural interest. OK by me.

Here is what the two slide-by windows and jambs will look like, more or less, in Sketchup:

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And here is where I am now with the jambs. Dry fit and some linseed oil paint primer on the end grain.

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It gets more complicated since this exterior jamb overlaps an interior stool that is joined and fit tightly to the shed frame.

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The odd mortices at the end of the stool accommodate a spline that joins with the post. It is hard to describe and illustrate how this works but here is an image from a Japanese carpentry text that may explain things. One end of the stool has a tenon, the other has the spline.

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And my version of that morticed end. Later filled by a spline and two little loose stub tenon that are not shown. The spline prevents the stool from bowing up and binding the window. The little loose stub tenons prevent the stool from moving horizontally into or out of the window opening.

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This may be confusing to you all since it certainly was to me. But I think I have it right. I'm happy to explain better what I am doing if you have questions.