I'm helping my coach build out his new gym space and he wants to do a floating floor. It seems the gymnastic foam is less bouncy than old tires and cheaper than gymnastic springs, so that's the plan. I was going to double-layer 1/2" OSB, covering all seams, and screwing the two layers together. Any tricks/tips? We'll be using 2" Dollamur flexi-roll mats on top.
Also, I found a place that sells remnant OSB in 2ft x 4ft pieces. This would save us about $400 over 4x8 sheets, but I'm worried about all those extra seams.....thoughts?
We share a facility with a gymnastics group at a ymca the sprung floor is great to take falls on, all we do is put our mats on top of the carpeted sprung floor to avoid carpet burn and because hygiene
We built the same floor when we opened six years ago. Here is my advice. Definitely screw the two layers of OSB together and DEFINITELY place the foam blocks all the way to the edge of each sheet of OSB. If you don't, you will develop weak spots over these joints where the two bottom layers meet (especially at the four corners). For a couple years you don't notice because the top layer locks them tight, but after a lot of falls and some big guys rolling/running on it, you will develop holes! We had to pull our entire mats a couple of years ago and reinforce the edges of each OSB bottom layer. Now its perfect without gaps, dips, or holes.
About 25 years ago I used tires, 1x12"s and 3/4 plywood. Covered in two layers of old carpet and tarped, it's as good today as when built. i have no idea where you get the idea the tires are bouncey, the foam in the pictures is more wobbly than a properly constructed tire mat. BTW, look for plywood and tarps at sign companys, the plywood is usually only a 1/4 but just double it up. Most of the components can be found free or close to it.
Thanks guys! Kevin, would you use plywood if you had to do it over again? A lot of the expensive gymnastic floors use 3/8" baltic birch ply but they are looking for more spring and not so much absorption. I have noticed in seeing other people's judo/bjj builds, they screw along the edges of the top layer. I would think it's better to secure along the edges of the bottom layer, no?
I know AOJ went with tires, so I'm sure it would work fine...but I don't even know where we'd get junk tires for cheap here in So Cal.
Tire dealers have to pay to have old tires recyled, most are happy to have you haul them away. The sign companies will usually let you have the old billboard plywood for hauling away also, you may have to pay for the sign tarps, but they will last forever. Office buildings being remodeled have a ton of carpet that they pitch.
I'd like to suggest construction adhesive between the layers of OSB. It will help bridge irregularities between the sheets. It also reduces the shear stresses on the screws so they are less likely to break or work themselves loose from movement
My concern is that a solid 1" layer of OSB will be so stiff it will negate the benefits of the foam. I do like the idea of taking stress off the screws, though. I'm leaning towards 3/8" plywood with screws and adhesive......
I did this years ago after a freak storm ripped off our roof and soak our antique floors, creating all kinds of cupping and irregularities. There was no other way to puts mats on it after that (building wouldn't replace it).
We did the 2 layers of plywood (I think it was 1/2 inch) and screwed them together, and it worked great. Kevin is spot on about making sure the foam goes out to the corners of the sheets underneath. The rigidity of the double sheet will not take away the benefits of the foam. It was a delight doing falls on the mats after we lifted it.
Be careful about where the floor transitions from mats to anything else, if that applies. We had problems with this because it was only a portion of the floor, and first our tatami mats would slide off. Then when we contained them, people were forever catching their foot on the border. It took a few iterations before we made something that felt comfortably safe.
Stupidnewbie - My concern is that a solid 1" layer of OSB will be so stiff it will negate the benefits of the foam. I do like the idea of taking stress off the screws, though. I'm leaning towards 3/8" plywood with screws and adhesive......
the entire floor absorbs the impact, as long as you have a few layers of carpet or 1/2" mats, it's fine. 3/8" is way too thin, you're in for a total failure and possible serious injury. 1/2" plywood,not OSB, will skate by if you only do mat work with no takedowns. 3/4" plywood is perfect and will last forever. Use 1x8",or even better 1"x12" across the top of the tires and screw the plywood to the boards. Source. I've built and used these mats since the eighties.
I trained on tires for years - didn't notice the bounce.
In fact I helped install the tires under the floor that I trained on. When I arrived to help I thought we would be packing the tires edge to edge - was kind of surprised how widely they were spaced out
