Kitchen Remodel – 1

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Continuing on from the last post… with the old doma gone I could proceed with structural work for the kitchen. But before diving into that lets take a step back and look at some photos from when we first moved into this house, now nearly two years ago.

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The house when it was first built 120 years ago, had a ground level space called the doma, which was the main area you would first enter into. The doma space typically acts as a sort of flexible utility/kitchen space.

At some point the doma in our house was renovated, the floor was raised, and the space was divided with walls, creating a dedicated kitchen as well as a formal greeting room to entertain guests.

When we first moved in the kitchen looked like this:

My guess is that this was a renovation done sometime in the 70’s. The door on the far right is the passageway to the old doma which got torn down in the previous post.

The next photo shows the front greeting room.

From an aesthetic point of view, the front room was in decent condition, but the kitchen was in desparate need of a remodel. Structurally however things were a little more concerning. The construction of these two rooms involved raising the floor off of the original ground level doma, but doing so created an air space without good air flow below the floor. And it was clear that built up moisture was causing things to get musty, and parts of the kitchen floor were clearly spongy from the wood rotting.

So within the first couple of weeks that we were here I decided to tear apart these rooms to expose the underlying structure. In the process I also opened up the ceiling revealing the roof structure.

With the ceiling and walls down you could see the original structure of the building which had been completely hidden. The beams are all hewn with chouna (Japanese adze). It was pretty thirlling to discover and expose all this amazing woodwork.

With that intial demo done, we took a pause to focus on to other areas of the house while we pondered the best way to move forward with the kitchen/doma space.

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So now jumping forward in time to just a couple months ago, just after the old doma was demolished, it was finally time to continue on with this part of the project.

Initially I had planned to return the doma to it’s original condition by bringing everything back to ground level. However after demolishing the old doma, and assessing more of the underlying structure, I decided it would be best to keep the raised floor. That said the existing raised floor needed to go, as it had decayed pretty poorly in some areas from moisture buildup. (The space became chaotic as we conitnued to live in and use the kitchen while also moving forward with the renovation work.)

This part of the floor was particularly bad, and every time you stepped up to the fridge you could feel how soft and spongy the cheap laminate flooring had become. So all that had to go…

It was also time to finally do away with the old faux wood panelling on the walls.

With the raised floor out of the way and the structure more fully exposed I could get a better assessment of the situation. The east wall of the house (wall on the right side in the photo above) went all the way to the ground level, and the wall rested on a sill beam. The sill beam was badly rotted out, and needed to go. You can see a portion of it below after removing it.

Here’s another chunk of sill beam after cutting it out.

Termites and decay had rotted out so much of the interior that the beam just split in two as soon as I cut it out.

Given the situation I decided to deal with the kitchen and doma in a similar way to how I dealt with things on the back of the house. That meant removing the rotted sill beam and raising each post up onto new stones. At the same time I needed to put in floor joists to support a new floor structure. With the posts raised onto stones the new floor would then have open airflow eliminating moisture buildup.

Doing that work meant fully tearing open the east wall of the house which you can see in process below. With the wall open I started by jacking up each post, removing the rotted sill beams and temporarily placed blocking below each post to level the building out.

From there I started laying out joinery for the new floor joists to go in between each post. Determining the sizing and type of joinery required a fair amount of head scratching. I took my time to think about how much material I had to remove, and how much I could leave. In otherwords, it was all about finding the right balance of strength for the floor joist, while not removing too much material from the post. I definitely took a lot of inspiration from what I had learned working with Somakosha.

The upper portion of the mortise will house a floating tenon that passes through the post, joining the two neighboring floor joists. Below that is a stub tenon, followed by collar tenons running along the sides. This style of joint really balances strong engagement while minimizing the amount of material you have to remove from the post.

I started by cutting the through mortise.

And from there it was the stub tenon mortise, followed by the mortises on the sides for the collar tenons. I did most of this work with an auger drill, trimmer router, and chisels. On this first one I got a little carried away with the auger drill…

The neighboring corner post meets with another more recent (maybe 1980’s?) addition to the house which is made primarily of concrete block.

In order to properly cut the joinery for the floor joist I had to make room by knocking out some of the concrete. Eventually I’d love to redo the concrete part of the building as well, so doing a bit of demo was no problem.

One of the joinery conundrums for the floor joist was the location and size of the joists relative to the bottom of each post. There was already an established floor height that I needed to maintain, and for the given span of each joist the height need to be 180mm tall. The distance from the bottom of the joist to the bottom of each post then became fairly short (around 150mm), and initially I was hesitant to cut joinery for the full height of the floor joist for fear of causing the bottom of the post to split. In the previous photos the mortises were only 2/3 the height of the joist, but after mulling it over a bit, I decided to extend the collar tenons down for the full height. That way there would be full engagement for the full height of the floor joist (and full beam strength), and also more resistance to twisting, while also still minimizing how much I needed to remove from the post.

So with the sizing of the mortises sorted, I moved on to laying out the tenons on the floor joists.

First step, cut the end and remark the reference lines down the end grain.

Then I used a circular saw and roughed out the tenon cheeks doing a vertical rip cut.

From there I used a circular saw again to cut the shoulder for the stub tenon. Once the shoulder was cut I used a kiwa-ganna (corner cutting plane) to trim the cheeks of the tenon down to the final dimension.

After repeating the above steps for the collar tenons, I then moved on to roughing out the slot for the floating tenon. I used a circular saw to establish the sides of the slot, and then roughed out the waste with an auger drill.

And followed up with a bearing bit in my router to cut the final depth.

One more detail was to flip the joist over and cut out the lower half of the stub tenon. I used an auger drill to rough things out…

… and clean things up with chisels and the router again.

In the end this is how the joist joinery came out with the extended collar tenons.

One final detail was to cut the angled slots for the shachi-sen (trapezoidal wedges) which will eventually be used to lock the floating tenon.

And of course the exposed faces were cleaned up with a hand plane. The material here is air dried hinoki, and it was a joy to plane.

It’s always satisfying to get a smooth finish over knots. Once again air dried timber helps in that regard.

That’s all for now, but there’s a ton more to share, so stay tuned.

Thanks for reading.