Junk in your J-trunk (room)

[Wage Slave]

No weight up there? Did they build with used chopsticks and cardboard or did they take "stick frame" literally?

The dangerous reverse pendulum effect, disastrous during quakes... You know like those fucking elevated highway they build everywhere with T shaped pillars. That collapsed so gracefully in Kobe...l

Exactly the worry. The house is light steel frame rather than heavy steel frame so that may make a difference. As far as I can make out, It relies on a large number of fairly light steel girders arranged in a fairly dense cage with strategic panels in the corners built much more strongly. There isn't any doubt it will withstand a quake well but is a product of fairly careful design and calculation rather than brute force over engineering. Hence, mess with it at your peril was the consensus.

My home was built by Sekisui House 15 years ago. Main steel frame is 3.5 mm thick or so (I have to measure to get the exact thickness), with beams shaped in a エ form that is 200 mm high and 100 mm wide. There are also thinner beams, shaped in a コ form with height 75 mm and width 45 mm (I don't have the measurements of the thickness of the steel at hand).

Covering the whole attic with a floor would add about 1000 kg, assuming I use 15 mm concrete panels (コンパネ). It may be an option to use 12 mm and laying the floor in only part of the attic to save on weight and cost. Even a floor of 25 square meters up there would be very useful.

Design safety factors of each structural member in a building is typically around 2.0, which I assume may be applicable in this case too. This is relatively low, because loads are well understood.

Yep, maybe I should reduce the floor space up there...

That sounds pretty similar to mine except you describe it far better. One across the road was demolished recently so I got a glimpse of the wall structure too and it is similar to your description too except for the special panels in some corners.

Seriously, invite Sekisui to quote on the job. They will turn up with a whole bunch of file drawings and data on the house. The guy who showed up here was happy to leave some of it with us and talk about other aspects of the house in some detail. Nice people but for our extension the way they insisted on doing it was very proper but just uneconomic. The local builder had a better solution involving building around the balcony rather than removing it and not attempting to integrate the two structures.

[matsuki]

Covering the whole attic with a floor would add about 1000 kg, assuming I use 15 mm concrete panels (コンパネ). It may be an option to use 12 mm and laying the floor in only part of the attic to save on weight and cost. Even a floor of 25 square meters up there would be very useful.

Why not use wood??

My place is around 25 years old, and it withstood that freakin' earthquake (6+ or something ... damn it was strong). All traditional wood frame construction, but thankfully after the big change in the architectural regulations.

There was, however, a bit of damage to the roof. Not serious enough to cause leakage, but it does need to be fixed, so this is how Hammer Manor looks today:

RoofRepairs.jpg

The building in the foreground on the left is my shed/workshop, which is the potential trouble spot for "stuff".

Glad to hear it survived with minimal damage...did your insurance step in at all for the roof repairs or was that all you?

That workshop looks fun! I noticed many of the inaka homes here have man-caves like that in the front yard.

[Russell]

Covering the whole attic with a floor would add about 1000 kg, assuming I use 15 mm concrete panels (コンパネ). It may be an option to use 12 mm and laying the floor in only part of the attic to save on weight and cost. Even a floor of 25 square meters up there would be very useful.

Why not use wood??

コンパネ is plywood used for paneling concrete. I like it because it is made stiffer than other plywood types to resist the weight of the concrete. It is also water resistant to a certain extent.

[Yokohammer]

Glad to hear it survived with minimal damage...did your insurance step in at all for the roof repairs or was that all you?

That workshop looks fun! I noticed many of the inaka homes here have man-caves like that in the front yard.

Unfortunately, on the advice of a relative who is now permanently on our shit list, we only bothered to get fire insurance when we moved up here in 2009. I can assure you that we have full insurance now though. The repair costs will not be too high (although any repair costs for a house can be kinda scary).

The man cave ... yeah, it's great. I'll try to take an interior shot or two when I'm not in the middle of a project with wood and tools strewn hither and thither (right now I'm building some bass traps for my studio .. what a mess).

[Yokohammer]

コンパネ is plywood used for paneling concrete. I like it because it is made stiffer than other plywood types to resist the weight of the concrete. It is also water resistant to a certain extent.

Regular structural plywood ... 12mm or 15mm thickness ... should be fine if the beams are spaced closely enough. I mean, it's just for "stuff," right? You're not going to live up there, are you?

[Coligny]

My place is around 25 years old, and it withstood that freakin' earthquake (6+ or something ... damn it was strong). All traditional wood frame construction, but thankfully after the big change in the architectural regulations.

There was, however, a bit of damage to the roof. Not serious enough to cause leakage, but it does need to be fixed, so this is how Hammer Manor looks today:

RoofRepairs.jpg

The building in the foreground on the left is my shed/workshop, which is the potential trouble spot for "stuff".

Isn't that one of those super heavy tile roofs ?

[Russell]

コンパネ is plywood used for paneling concrete. I like it because it is made stiffer than other plywood types to resist the weight of the concrete. It is also water resistant to a certain extent.

Regular structural plywood ... 12mm or 15mm thickness ... should be fine if the beams are spaced closely enough. I mean, it's just for "stuff," right? You're not going to live up there, are you?

Nope, I have no plans (yet) to live there. Anyway, clearance is insufficient to stand up. Important is that I won't be walking around there regularly, so there will not be too much strain on the floors.

Beams (to be installed and made of wood supporting on the structural steel beams) will be spaced about 40 cm apart, so yeah, 15 mm will do, according to some sources on the interwabs. Even 12 mm may be fine, though it feels much less stiff than 15 mm. Considering availability and cost, I still may settle for 12 mm.

Major worry is if it's strong enough in case I store boxes of books and documents...

[Yokohammer]

My place is around 25 years old, and it withstood that freakin' earthquake (6+ or something ... damn it was strong). All traditional wood frame construction, but thankfully after the big change in the architectural regulations.

There was, however, a bit of damage to the roof. Not serious enough to cause leakage, but it does need to be fixed, so this is how Hammer Manor looks today:

RoofRepairs.jpg

The building in the foreground on the left is my shed/workshop, which is the potential trouble spot for "stuff".

Isn't that one of those super heavy tile roofs ?

Yup, heavy tile roof.

But apparently the weight of the roof is part of the overall design, and actually helps to keep the building stable.
People who have replaced their heavy traditional tile roofs with lighter alternatives, in the mistaken belief that lighter is always better, sometimes run into serious structural problems later.

[Russell]

Glad to hear it survived with minimal damage...did your insurance step in at all for the roof repairs or was that all you?

That workshop looks fun! I noticed many of the inaka homes here have man-caves like that in the front yard.

Unfortunately, on the advice of a relative who is now permanently on our shit list, we only bothered to get fire insurance when we moved up here in 2009. I can assure you that we have full insurance now though. The repair costs will not be too high (although any repair costs for a house can be kinda scary).

The man cave ... yeah, it's great. I'll try to take an interior shot or two when I'm not in the middle of a project with wood and tools strewn hither and thither (right now I'm building some bass traps for my studio .. what a mess).

That looks like some serious workshop from the outside. Yay, some pics will be great.

My workshop is not yet properly set up and used mainly for storing stuff. I basically do not have enough space to work there. Did I tell you I need storage room under the attic?...

[matsuki]

You guys both have the jump on me...all my tools are stored in the kitchen and after 2 days of both of us going at it with Japanese weed whackers (picture a table saw blade on a pole) we have only managed to clear away the forest/jungle from the parking area of our build site. I think it's time to call in the bulldozers...

[Coligny]

Try with goats...

Mah 12 tatamis delivery room/workshop is so dirty and crowded that I barely go there... Plus there is no more working aircon... Dad called the power company to lower the amp service for the 200v since we don't use the XRay masheen anymore (who was a huge 200v hog) and those idiots from the power company cut the 200v line going to my floor. Who was powering the workshop aircon... Down to fridge temperature in full japanese summer...

[matsuki]

I'd call Greji up for some goats but that would require fencing in the area...and this place is biiiiiiig! Plus, I don't want to see what happens when wild monkeys meet goats.

All zeee Americans say "Use a brush hawg!" but so far I can't find one in J-land and what I've seen here isn't too impressive. I soooo wish I could buy one of these...

[Russell]

I like the top comment on this video:

This is the perfect way to get around in case of a zombie apocalypse!

[Coligny]

Living this here:

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[Taro Toporific]

Here another king of Japanese Junk-in-the-Trunk...

hermes.jpg

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Read the rest-of-the-story of the Trunk Monsters at RocketNews24: What in the world is going on at Hermes in Shibuya??