[varrozans]

This is interesting as I was told that the floor in Noma Dojo did not have springs. Yushikan Dojo in Tokyo is a private dojo run by Takahashi Sensei. I was told he copied the design of the Noma Dojo for his floor which he built himself.

The design he used was arched joists. You can clearly see the upward curve of the floor from the edge to the middle as you stand back and look at it. It is very springy and gives great energy to your footwork.

Tokaidai put in a sprung floor in their dojo and the students began having leg injuries. Seems the floor is too springy.

My home dojo is on the second floor so the spring is derived from downward deflection into the space below. With enough people in there it will suck the door open if it does not get latched.

I would really like to see those pictures.

[CoenceLomneedtrue]

I would really like to see those pictures. I'll see what I can do.

[Kokomoxddcvcv]

Excellent!

I am interested in learning how you decided the spring rates. Did you just get them "off the rack" or did you have them made?

Looks to me that your main beams are approx 4x12 laminated and scarfed with 4x4 on top and 2x6 flooring.

I see the finished floor is not toung and groove. Did you glue them? Any concern about shrinkage?



We are hoping to break ground next year on a dojo. The outside is not a problem it is the floor that interests me the most. I have been thinking about springs and I like what you have done. Also tires are a possibility and some other thoughts. What were your considerations in deciding this final design?

Actually I have a million questions but these will be good to start.

[Indian Butt Magic]

Wow,
good questions.

The springs were custom made. They stand well over 1000kg each and the boards will spread the weight evenly so they are more than enough to stand our practise.
We talked about car tires but had the good chance of getting the springs quite cheaply.

The flooring is grooved from underneath and attached to beam with hooks made from nails.
If you look at pictures at:
http://aky.kuvat.fi/kuvat/Kendo/Dai+...rakennusvaihe/
you'll find pictures of both the hooks and the grooves. This way there will be no nails or other sharp things on the top of the floor.
Also the middles of the boards sides have small grooves and they are attached to each other by "cookies" made from wood.

Yes there will be some shrinkage, so we will do the final tightening of the floor in wintertime when its most driest.

Sorry, I'm not a professional builder so my answer may be somewhat vague,
but I can ask our dojo-building-senseis and get back to you afterwards.

[casefexas]

This looks awesome, there's a whole Scandinavian forest in there - yummy. So much effort but I'm sure it'll be worth it.

[Gometesstem]

What are the construction costs involved for that? At my current dojo we just built a floor for ~3800sqft or so using cork and flooring (i think it was in the niehgborhood of ~5k or so). building a truly sprung floor was going to be quite costly.

[pongeystrhjst]

Our community center is in the midst of rebuilding as well. They just replaced the parking lot, but the Dojo itself needs some repair, holes, blood splatters on the wall, you know, the usual.

[inhitoemits]

What are the construction costs involved for that? At my current dojo we just built a floor for ~3800sqft or so using cork and flooring (i think it was in the niehgborhood of ~5k or so). building a truly sprung floor was going to be quite costly.

A 60x60 floor for $1.30 sq foot sounds really cheap unless you hijacked a lumber truck.

About the cheapest finish floor I have found is T&G pine at about $1.50 sq ft. which does not count your cork underlayment. BTW, T&G pine makes a really nice floor (3.5" x 5/8 thick over two layers of 3/4 plywood) cost approx $3.00 per foot plus whatever your cost for the foundation.

I would guess that the 4x12 beams shown would cost you about $250 to make a 32 footer. On 8' centers you got 6 in a 32x48 floor for $1500.

Next they have 4x6 on what looks like 4' centers for another say $1200

Plus extras (springs+ $$$$)

My guess for rough floor would be in the neighborhood of $5.00 per foot (2x6 finish floor might be more, I have not priced lumber in a while)

total for 32x48 about $8000 plus labor plus all those little things that double and sometimes triple the price so I guess about $16,000- 20,000 plus the building.

If you gave it a whole lot of thought and were the GC and built it like the egyptians build the pyramids, i.e. slave labor, you could build a nice 1600 sq foot dojo for about $60,000 plus the cost of the land.

[accotMask17]

60K? Do you get heating, plumbing and insulation for that price?

[Aluback]

60K? Do you get heating, plumbing and insulation for that price?

yes for insulation, no for plumbing and heating. The location I have is such that we only need heat in the dead of winter. Since I have a nice woodlot I might use a couple of wood stoves in the dead of winter if it were used then. Cost about $4000.00 Woodsplitting training is fun. kind of like whitewashing fences.

Kitchens and bathrooms are usually the most expensive part of a building I think. A standard septic system in my neck of the woods would cost probably $20,000. Start putting in bathrooms and kitchens and you easily double the price. $80-100 sq foot with no profit margin would be about right.

I envision a separate building for showers and composting toilets (which are expensive right now). Essentially the dojo we are planning is a barn with a really nice floor.

I only need to deal with grey water then. As for getting the water, I plan a 4000 gallon water tank on the ridge about 70 feet above the site which will also supply water to the surrounding orchard. Water is drawn from a pond below via jet pump powerd by either solar or wind and heated with on-demand propane water heater.

Biggest problem will probably convincing the local government that it is ok.

That and gettng the money.

I already own the land.

[actifadepette]

Well if you don't have plumbing then the heating isn't so important. My judo club is in a machine shed at the instructor's farm. They just fire up the heater an hour or two before practice.

With a nice wood floor I'd be a little worried about cycling between extreme temperatures though.

But now that the Y's replacing the floor, I've got no motivation to build. We get everything we need (good floor, showers&lockers, central location, storage space for club crap) for way cheaper than we could ever do it on our own.

[CreativeAcrobate]

Well if you don't have plumbing then the heating isn't so important. My judo club is in a machine shed at the instructor's farm. They just fire up the heater an hour or two before practice.

With a nice wood floor I'd be a little worried about cycling between extreme temperatures though.

But now that the Y's replacing the floor, I've got no motivation to build. We get everything we need (good floor, showers&lockers, central location, storage space for club crap) for way cheaper than we could ever do it on our own.

With the temp usually comes the changes in humidity which is what screws up the wood. I think though that giving it some thought and building at the right time prevents lots of problems. Luckily my son has tons of experience building furniture (and having it warp or crack) and we have learned a thing or three.

Mostly I'm just interested in building to give me something to do while I'm waiting for my big ticket to get punched.

[ENGINESSQ]

total for 32x48 about $8000 plus labor plus all those little things that double and sometimes triple the price so I guess about $16,000- 20,000 plus the building. I think your quite near to our estimate of something like 20,000 euros.

We're lucky because we hire the space and it includes dressing rooms, showers and sauna so we didn't have to buy the land or house.

We have got from our sponsors or bought with money from sponsors everything you see in the pictures. So getting good sponsors has been what makes this all possible.

Also, all the work has been done by club members so no cost's there either, plus it has had great effect on club morale too.

[Preorbtat]

With the temp usually comes the changes in humidity which is what screws up the wood. I think though that giving it some thought and building at the right time prevents lots of problems.

What's the right time when your local temperature range is -40C to +40C?

[obegeLype]

What's the right time when your local temperature range is -40C to +40C?

The driest time is best for furniture and musical instruments because swelling up won't destroy it but shrinking will. So my guess for your local would be winter with the heat on. Bring the wood inside and let in acclimate for a week before you install it.
If you leave about 1/4 inch around the perimeter and make the finished floor free floating, when it swells it won't buckle (too much)

The Finland dojo looks like the floor is pretty much a slab with the "cookies" (we call them biscuits) glued in and the planks glued together.

[Aztegjpl]

I'm not so sure using biscuits and glue is the best idea for a floor that is going to be nailed to joists. Won't it buckle with weather changes?

[freddystone]

I'm not so sure using biscuits and glue is the best idea for a floor that is going to be nailed to joists. Won't it buckle with weather changes?

From the pictues it looks like the floor is not nailed to the joists but is floating. That is a heavy slab so it ain't like it's going anywhere.
I might have put an inch of rubber between the joists and the floor though.

Off to kendo class for me.

[anenselog]

That looks like it's gonna be one nice dojo! And congrats Neil ....bet that new floor will be sweet. The Ukrainian Federation Hall (where we do our sunday classes) just refinished their floor. Really nice to not have to worry about splinters anymore, but damn, is it ever sticky right now! You can't really slide along too well until you get a nice coating of dust and dirt on your feet.

[86GlSqSK]

From the pictues it looks like the floor is not nailed to the joists but is floating. That is a heavy slab so it ain't like it's going anywhere. At the moment the floor is not nailed to the joists. We will do that in february or march when the wood has dried. For now, we will nail only the ends of every board so we can use it for training. But as Ignatz said, the floor is so heavy it's perfectly ok to use.

Also as we don't use any glue, opening the floor again in winter to tighten those gaps that are caused by drying will be much easier this way.

[Nesskissabe]

What was yourthinking behing the butresses at the ends of the main beams? (the 45degree things that connect to the walls?)