Build a cushioned dance floor

This page shows the process I used to build a cushoned dance floor. The only tools needed are utility knives and a circular saw. The project took one weekend to complete. I got all the materials and cut out 4 mat's worth of 3" tiles on Friday night. The subfloor was completed on Saturday, and the "marleys" were installed in a couple hours on Sunday.
(NOTE: Click on any image to see a larger version of the image)

Inspiration

My kids are heavily involved in Irish dance, and practice for hours every week. When we moved from Cincinnati, OH to Jacksonville, FL, we were unable to take the dance floor I had built out of plywood and 2x4s. With the opportunity to build a new floor, I wanted to make it as safe as possible for my kids, and to fix a couple complaints I had heard about the old one. On our first trip to the new dance studio, I asked the teacher about her floor, and she let me take one of the cut-off pieces of the floor she had installed. It looked like a standard EVA foam mat glued to the bottom of a tongue-and-groove OSB panel. It looked easy enough.

A Family Affair

If you're building this for your dancing child, your dancer should be able to help, regardless of age. I had the help of 4 of my dancers - ages 7, 9, 14, and 17. The younger kids were very helpful in peeling the papers off the double-stick tape so I could put them in their correct place on the OSB (my 9-year-old could put some blocks on that didn't require measurement), and the older kids cut out squares from the mats and applied double-stick tape to them. The two older boys installed the "marleys" mostly by themselves, under my direction.

Sources

A quick DuckDuckGo search showed that the piece of floor I'd been given was likely a Springstep IV-D panel, which retails for $18.50 per 2'x2' panel ($4.625/sqft). It is made from a 5/8" OSB panel with "L"-shaped foam forms on the bottom. Further research on the StageStep website showed that they also sell 3"x3" self-adhesive foam squares. Looking at their 2020-2021 edition of their Flooring Guide also proved helpful, as it provided a layout for 3" squares on a 4x8 sheet of plywood.

Supplies

These are the supplies I used to build my floor. The quantity is based on my project - an approximately 19'x20' 2-car garage. The prices do not include sales tax.

Item	Description	Link	Price Each	Quantity	Total Price	Price per Square Foot
EVA Foam Mat	12-pack - We Sell Mats 1 Inch Thick Martial Arts EVA Foam Exercise Mat, Tatami Pattern, Interlocking Floor Tiles for Home Gym, MMA, Anti-Fatigue Mats, 24 in x 24 in	Amazon	$118.74	1	$118.74	$ 0.31
Tongue & Groove OSB Subfloor	23/32-in x 4-ft x 8-ft Tongue and Groove OSB Subfloor	Lowe's	$40.38	12	$484.56	$1.28
Double-sided Mat Tape	Meister Double-Sided XL Floor Mat Tape - Secures Exercise Mats & Rugs in Place	Amazon	$14.99	2	$29.98	$0.08
Gorilla Tape	Gorilla Tough and Wide Black Duct Tape 2.88-in x 90-ft	Lowe's	$14.98	2	$29.98	$0.08
Shower Pan Liner	Oatey Shower Pan Gray PVC Shower Pan Liner	Lowe's	$6.78/linear foot	80 linear feet	$542.64	1.43
Total Cost:					$1205.90	$3.18

Process

Cut the foam blocks and apply tape

Cut the foam mats into 3"x3" squares using a utility knive and straight edge. I laid out four mats with their edging, and measured 3" from each end and cut about 80% through the mat. After cutting all the cuts this way in one direction, I cut all the way through the mat perpendicularly every 3 inches, making 4' strips that were 3" wide and were mostly cut through every 3".

Initially, I cut each block out and when I had enough for one sheet of subfloor (52), I would tape them individually by placing a block on the stick side of the tape, and the cutting at the edge of the block. After doing this for a couple sheets of subfloor, I placed the entire strip on the tape and then cut through the tape and the rest of the foam at the same time. This proved to be much faster.

Add the blocks to the OSB

Using these measurements, I added the blocks to the bottom of the OSB. I measured from one side, then the opposite side. All measurements are approximate - there's no need for absolute precision in positioning the blocks. Using a T Square, I was able to place all the blocks on one long edge, and then use the square against the side of those blocks to place the others in line with it at their required measurements.

Install the floor

Put down the floor. Match up the tongues and grooves, and cut to fit. Fit factory edges together as much as possible. If you need to hammer a sheet of OSB to secure the tongue into a groove, use a pounding block so you don't damage the tongue or groove you're pounding on.

Install the "Marleys"

40 mil PVC Shower Pan Liner makes a great substitute marley. It's not cheap, but gives a decent dance surface for a fraction of the price of an actual marley. It is sold at Lowe's by the linear foot (in a 5-foot width), and buying more than 15 linear feet gives you the a 15% discount. If you're getting a lot, check the supply online for your local hardware store. Sometimes they won't have enough in stock and you'll have to go to a different (or even multiple) stores.

To tape the marleys down, we tape both long sides of the first marley to the floor, with 2.88" Gorilla Tape, and then place the second row next to the edge of the first marley, over the tape, and then tape both sides. If you tape in the same way, you will need twice as many linear feet of tape as you have shower liner, plus 10 feet per strip of pan liner (for the short ends).

Cleanup

The PVC marleys can have some off-gassing and may have a toxic film. You should wipe down the surface of the shower liner with some light detergent or a vinegar/water solution and open the windows to let the fumes escape.

Dance!

That's it! Now get your dancers (who hopefully have helped you put this all together) and DANCE!