I have two issue that needs to be answered.
The background is that the deadlift platform will be located in the backyard placed on brick flooring which will be covered by shelter. The plywood would consist of three 15mm thickness. x 3 so that is 45mm thickness in total.
I am plan on getting a cage that is 220mm by height and do i want to place the cage on-top of the platform but due to the ground and ceiling it will be too tall. I was thinking if i was able to take off the brick flooring and leave the sand and ensure that the ground is flat and levelled for me to put the platform and the cage ontop.
Another issue is that I don't really know what kind of plywood i should be getting for myself, as I have heard OSB is the one to go too, but I have been told other wise to have marine plywood to ensure the wood is stronger and stable due the wood being in the weather more than the OSB
Welcome to the Bunnings Workshop community @IceCream. It's wonderful to have you join us, and thank you for sharing your question about what boards to use for your deadlifting platform.
You heard correctly, Marine Plywood is made for exterior use and is far stronger than ordinary plywood. OSB - oriented strand board is constructed much like MDF and that it's sandwiched timber with timber glue holding it together. They are both prone to moisture damage. I recommend having a look at this discussion - How to DIY a weightlifting platform and which type of plywood to buy?. You might find my recommendations for the build applicable to your project.
Your other option is to make your platform smaller so that the cage sits on the ground and the platform inside it. Is there a reason why we can't have the cage on the brick floor? If you still proceeded with plywood, I recommend Marine Plywood to make sure that it will withstand the weather. My only other suggestion for your build is to put Gym Tile with beveled edge 1x1m Rubber Blk High Dens at the bottom. This is so that the plywood will not be in direct contact with the ground and will last longer.
If you need more advice or information, please let us know.
Thanks for the reply @EricL
Well the thing is that I cannot make the cage itself smaller than the original production as it come with the cables which I cannot mend to the height of my backyard ceiling - that being said the gym cage does have the bench for me to use so i dont have to adjust the height every single time i use it and change the seating to the correct height to ensure its the same level. If you understand that.
If the height is the issue you should be fine removing the brick flooring so that it fits in your backyard ceiling. Would it be possible for you to post a photo of the cage, its measurements, and the area where you plan on setting up your weightlifting platform? This will give us a better idea of the situation. Our members can then offer you recommendations on how to set it up.
We look forward to seeing the photos.