References page

I have no problems with an open invite to my dojo anytime we have a scheduled class.
Ikei,

After discussing by mail with Hatashita who’s built dojo subfloor I have decided to go with a 33 blocs configuration. In his case he always use 2 layers of 3/8” plywood but it cost a lot so I decided to go with 7/16” OSB. As John Graybeal I have a ceiling problem so I used 2 inches thick foam.

I made lot and lot of calls to finally found 48” X 108” X 2” with 2.2 pcf polyethylene foam sheets here in Montréal, Québec, Canada. We had used bench saw to cut the sheets in 3” X 48” X 2” and used a cut-off saw to get 3” X 3” X 2” blocs. It was very funny to catch blocs pitching by the cut-off saw, it come out very fast so it’s good to practice reflex. We finished with 2300 blocs and have used around 2000 of them under a first layer of 59 OSB sheets.

I know that the type of glue is always a problem, but in our case we used a water based cement contact “LePage” who works great. With that cement you will need to wait between 2 and 3 minutes before gluing blocs on wood but the blocs will not fall down when you will return the sheet.

The size of my Dojo is 14.3 X 12.8 meters (47 X 42 feet) and here is cost and material to build the subfloor:

Polyethylene : 4 sheets at 75$ = 300$ + tx for a total of 338.63$ = around 15 cent per bloc.

2” x 4”, screws, paintbrushes, duck-tape, fuel to carry material, lunch for everybody, etc. : 225.49 + tx for a total of 256.35$

I didn’t find used mats so I had to buy 18 new tatamis : 18 X 3’ X 6’ mats at 165$ = 2 970$ + tx for a total of 3 384,32$

After a complete week of training on the new floor, every judokas have the same comment, wow it’s so nice to fall that we now want to replace uchi-komi by nage-komi. I really want to thanks a lot for your help and let you know that everyone appreciate the comfort of our new dojo.

James
We finally got it all together and got the floor constructed. Your plans worked like a charm. Thought you'd like to know. The roll out wrestling mats feel so much better. Falling on them when it was on a concrete floor was painful. Now it is like falling on a cloud.
Thanks for the plans and advice.
Ernie erniedoss@uberpuppy.com

Yes, we've installed it and love it!!! Huge mat space of around 1,200 sq/ft.
We are in Costa Mesa, CA (Orange County).

Take care,
Bill D
billdeb@me.com

I never did thank you for all of the information you sent me about your judo floor. We built it earlier this year and it turned out great.

We have a large floor, approximately 24’ x 42’. We used Wisconsin foam for our ethafoam, going with the 3x3x4 inch blocks and gluing 33 blocks long side up on a 4x8 sheet of 7/16 osb plywood. Instead of using butcher paper for the template for the glue, I cut the holes in a sheet of plywood in the 33 block pattern, then used it to mark each sheet using a heavy marking pencil. The sheets of plywood were light enough for one person to do all of the marking by himself and it resulted in every sheet having the same pattern. No problem with remembering to flip the butcher paper over.

We used the contact cement as recommended and went through 3 gallons gluing the approximately 1050 blocks to the 32 sheets of plywood.

We rotated the top sheets of plywood 90 degrees to the bottom layer and secured them with the sheetrock screws.

We covered the floor with Swain flexible mats which come in 6 foot widths and 42 foot lengths. To fit across the width of the room and secure it, one mat was cut so the map was fitted tightly between the walls, then regular molding was secured to the walls pinning the mat to the sub-floor. The ends of the mat were secured with 1 x 4 molding that was laid on the very edge of the mat and screwed through the sub-floor, onto a board that had been ripped to 4” to fit under the sub-floor in the space created by the foam blocks. The result is a rigid edge that does not give at all when walking on and off of the mat. Absolutely no problems with the mat moving at all. The seams between the 3 mats are taped with tape supplied by Swain and it lasts about 3 weeks to a month before it needs to be replaced, which takes about 15-20 minutes.

We all love the floor and it makes falling easy and comfortable. Total cost for the complete floor was approximately $5,500. 4,500 for the mats and 1,000 for the sub-floor. Not to bad for a great floor with over 1000 sq feet of surface area. It took four of us approximately 10 hours to do everything, from taking up the old mats to securing the molding. We started and finished on one long Saturday.

A couple of observations. We do a variety of martial arts at our school, ranging from Han Mu Do, a style very similar to Hapkido or KuK Sool Won to Brazilian jujitsu. Han Mu Do has many throws similar to judo but also has the same variety of kicks as Tae Kwon Do. To provide for a good base for the kicks, I believe you need a somewhat firm floor. That is why we went with the 33 block lay out and secured the top layer of plywood to the first layer with the screws. I think going with the 27 block layout or letting the top layer of wood float on the first would make the floor to soft and spongy for kicks. As it is, there is just enough give to the floor while kicking to require a little more attention to balance, which is a good thing.

Thanks again. Please feel free to have anyone contact me it they need any information on our floor. Bill Hidalgo

I noticed your question on your website: “If anyone can find out what they use in the ethafoam factory to bond the ethafoam layers let me know!!!”.

The industry standard method of joining pieces of PolyEthylene foam is heat bonding. There are basically three types of PE foam; molded into shapes, single-layer plank and laminated plank. At the foam factories that make laminated planks, large sheets are laminated in a large machine that melts and then joins the surfaces of the foam so that they are permanently bonded. Smaller pieces of PE foam can be bonded by using a heavy duty hand-held “blow dryer” heat gun. A third option is to use a hot plate with non-stick surface but these are not as easy to use and find as the heat guns. The key to using the heat guns is to focus the heated air and quickly join the pieces. A little practice will show you what I am talking about. On one hand, you do not want to create a puddle of melted foam and on the other hand, you do not want a weak bond. The bond should be at least as strong as the parent material.

As for reinforced vinyl mat covers, I found that the in general, the best sources are commercial truck tarp shops. Most good ones can make a mat cover as large as you need, and offer a variety of colors. I have not found the source for the rice straw tatami textured vinyl, though. Please let me know if you have a source, preferably in the USA. Thanks.

Hope this helps you. I would like to visit your dojo if I ever find myself in your area.

Hello Sir,

I wanted to thank your for your excellent floor web page. We recently installed a tire floor and found your page a great resource. Our floor page is at http://www.kattaekwondo.com/floor.htm Feel free to use it in your list of resources. We didn't really know what we were doing at first, but did a lot of trial and error on what works and we seem to have found a pretty good solution.

Sincerely,

Bill Pottle
www.kattaekwondo.com

The floor looks great. Iowa State U. built one and my boys have been to
three tourneys there. Now they want one of their own!

Thanks for making this available!

Thanks for the info on the web re: sprung floor
I did it to my personal dojo space / garage conversion
came out unreal!
I had to correct for a 2" slope, so I purchased different thickness blocks
from Wisconsin Foam (2 1/4" - 4 1/4", used the template for cementing the
foam to 7/16 osb plus another layer screwed down to 1st. Then put my
puzzle style mats back down.

3 days - 1 person with wife's help on occasion
Came out perfect!
Trained on it today with my private instructor and we were like kids again
Scott

Scott Sargent
EURO VIDEO
650-369-4366
http://av-workshop.com

Hi,

We just completed our sub-floor and its great. As soon as we were done, I took some big falls on it and it felt like falling on air. The plans were very helpful, thank you so much for sending them to me.

Looking at pictures from other dojos was very helpful so we decided to document everything we did to create the floor. Here are the pics and a short description of how we did it. Please feel free to share this information with anyone who wants it and feel free to post it on your website as well.

----------------------------------------

I was able to find the foam at a couple of different shipping stores up here in DFW. Sheets of 4X9 foam are around $85-95 dollars right now, but I found a guy who sold seconds for $65. The second piece of foam had one corner that was a little messed up but the rest of the sheet was perfect and it saved me around $30.

It didn't take long to mark the foam and cut it up with a knife. I went with 3X3X2 blocks. A longer knife works better and the dachshund pitched in a little too. In no time you have a stack of blocks ready to go.

Next, I marked a board for the template. I used a solid piece of board similar to a peg board. It is light but strong enough to make a lasting template for future use. I went with the 33 block layout because I like to have firm footing. After marking the squares on the board, I drilled out 3 of the 4 corners of each block for speed marking. Then I laid the template on the OSB and marked the holes with a marker (red works best). Then, I just glued the blocks in place with Heavy Duty Liquid Nails. It works best if you put some on the board, press the block on to it, and twist the block 180 degrees into place to spread the glue evenly on the block and seat the bond.

After all the blocks were in place, we would flip the boards over and put them in place. You don't have to wait for the Liquid Nails to dry, but you do have to set the board down flat. If you don't set it down flat or try to move the board, the blocks will shift on the board, so be careful. We had very little problem with the blocks shifting so I would say its safe to do it that way if your careful. Remember to turn the sheets on each row as indicated in the instructions so the blocks line up correctly.

We started screwing the top layer on as we went across the room. I think this is helpful because the bottom layer is unstable, so the less you have to walk across it with a sheet of OSB the better. You have to really be careful at this point and look at the plans. If you dont place the top layer 90 degrees and place it correctly on the floor, your not actually tying the floor together and it will do nothing for the stability of the floor.

After we were done, we laid the mats on top of the sub-floor (we have 4X8 swain tatami folding mats) and admired our finish product for about 5 seconds before we went and put on our gi's and did some aikido!!!

Foam $65
Glue, screws, template board $25
21 sheets of OSB $115

Total cost to build my sub floor - $205
Total time for 2 people - 8 hours

After several test throws on the new floor, I would have to say it was well worth the effort. The floor is very solid to walk on, but feels great to fall on. I am very happy with the result.

Thank you,
James Bedwell
Kaizen Dojo
http://sites.google.com/site/bedwellaikido/

james.bedwell@yahoo.com