I had bought three 4cm thick rubber mats to do power clean sets with the purpose of dropping the bar on the floor. Since I already lift over 80kg/176lb each time I find the weight too heavy to put the bar down with control and delicacy without dropping it. I have some bumper plates that I use to power clean and drop the bar calmly. And with weights of that magnitude it helps me to be fresher to face the next sets.
The fact is that after several months, I find that the tile floor (I think it's marble) is dented and cracked in the two areas where the plates hit when dropping the bar. I really didn't expect this, as many people who practice weightlifting assured me that the 4cm rubber was enough to protect the floor below.
I tried to fix it first by pouring dry concrete, but little by little it breaks again. At the hardware store they recommended that I remove the damaged tiles and make a formwork using Sikadur 42 epoxy resin. I called the manufacturer of the product and they told me that it was the most resistant material they had, but they could not guarantee that it would not break when I dropped the bar.
Does anyone know what material the base floor is made of under the rubber in gyms where weightlifting and CrossFit are practiced?
Tile is brittle and fractures easily, even if installed correctly, with the proper mortar type, preparation and placement, i.e., in small areas with the tile firmly pressed into the mud bed. It is particularly prone to impact damage. While rubber mats do dissipate energy, they don't dissipate all of it.
If you're not on a slab on grade, the flexure of the floor under load is going to make the tile susceptible to separating from the subfloor. Then you have a partially de-bonded tile that you drop a weight onto and it fractures at the location of the debond.
Just remove the tile from your Olympic lifting area. Even with mats, why would you drop a loaded barbell on a tile floor?
I forgot to upload an image in the start message for better understanding.
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The last time I fixed it with dry concrete I thought I'd try putting some newspapers down to level it properly. And after doing my power clean sets, surprisingly it didn't break. I don't know if this new fix will last me a while.
I'm guessing that 4cm mats (1.5" or so) are more for slowing down impact than they are for dispersing it, which is contributing to your problem. Platforms are made with multiple layers of plywood under a very dense rubber that's made for livestock (horses, cattle). This construction helps spread out the impact over a large area.
I'd see if you can remove the tile as Satch recommends, plus build an actual platform.
It's clear to me that the best option is to have a weightlifting platform. But I'm a little confused about the following. Let me see if I understand what you mean. You suggest that I remove the marble tiles on the floor. Correct? But what material do I put in place of the tiles and on top of the one that goes to the platform?
Satch's recommendation was to remove the tiles, to keep from having to worry about them, I'm guessing - that makes sense to me.
I'm guessing you're not in the US, Hugo - I'll describe things in US measurements, but I'm sure there's a close equivalent in metric terms, if that's what they use local to you. Platforms are easy to build with 4' x 8' sheets of 3/4" thick plywood. OSB (oriented strand board) is cheap and effective. If you have room for it, an 8' x 8' platform will provide space for your rack and space in front of the rack, giving you room to deadlift/clean outside the rack, as well as an unbroken level surface for using a bench inside the rack.
You put down layers of two 4'x8' plywood boards to make the 8' square, with the seam between the plywood boards rotated 90 degrees between each layer. Wood glue and screws hold the layers together. Two layers is good, three layers is better.
For your top layer, you can cover the whole thing with livestock stall mat. It's 3/4" thick, and generally comes in 4' x 6' pieces. It's made of recycled automobile tires, and it's dense enough that cattle and horses are steady on it. Because they are 4' x 6', instead of 4' x 8' like the plywood, you have to do some cutting to match the top size, but it's pretty straightforward. Screws through the stall mat will hold it in place to the top plywood layer.
Some people use plywood (nicer than OSB) for the middle section of their platform, with stall mat on the outer sides where the plates will be. This looks better, but stall mat is perfectly functional, and in my opinion easier to use across the whole top layer.
This gives you either 2.25" total platform thickness or 3", depending on whether you use two or three layers of plywood. Those layers of plywood are what provides the mass and stiffness to distribute out the impact of dropped weights over a large area, instead of having it focused into a small area of impact.
You want to make sure the floor is flat and level under the platform. You also don't want water leakage, because the wood can absorb that and swell, mold, etc.
If you just want a platform for deadlifting and cleans, you can do half the size with a 4' x 8' platform with single sheets of plywood, as well. If you have enough floor space to still fit a bench into your rack without having it on the DL platform, this should work.
Does that make more sense?
Thanks for all your input Jason. Yes, what you say makes sense. I had initially thought about building a platform from some of the sketches on YouTube like this one: https://www.youtube.com/watch?v=LcwjCrUDD6w
As you say, I don't live in the US and I'm more used to the metric system, but I did my homework on unit equivalence. Today I'm much more familiar with using inches, feet and pounds. I always use a calculator.
In the end I had decided to buy some 1x1m x 4cm thick rubber tiles. I had asked at a weightlifting club about flooring and they told me that this is enough to protect the floor from impacts. It's also a cheaper option. It turns out that when I recently told someone into weightlifting about my problem with the broken floor, he told me that the best solution was to build a platform. But he admitted that a few years ago he would have given me the advice to simply use 4cm rubber tiles, which is obviously not enough at least in my case.
So the composition of the stall mat is not the same as the rubber I had put down? (This is the link to my rubber tiles: Losetas de caucho de alta densidad especial para gimnasios. 43mm.) Could the material I have be used in the construction of the platform? Something that caught my attention was that the thickness of the stall mat (3/4" = 1.9 cm) was half that of the rubber tiles I had purchased (4 cm = 1,57").
And finally, removing the tiles from the floor below as you say makes sense because they break and I have more space in height. The question I had asked in the previous thread was regarding whether once the tiles are removed, the platform is mounted directly on the surface below the floor without tiles (which I don't know exactly what there is). The question is whether there is no danger that this floor can also break due to impacts and it is necessary to fill it before building the platform with another material. But if as you say, the structure of the platform itself is strong enough, the material of what is below should not matter much as long as it is flat and level.