Plastic can be found floating in the ocean in barrels on vacated rafts and in loot boxes.
Use plastic sheet on raft.
You can purchase huge sheets of these and cut them to fit the size of your tank or tanks.
And then laying of reinforcement is done on spacers over the foundation bed.
Uses edit edit source plastic is used to make.
Using 4 plastic barrels building a fram around them would make a raft that will maybe out last you.
Today most experts feel very strongly that engineered films designed specifically for use as vapor retarders should be used as vapor retarders.
Plastic is used for 18 different items including the raft foundation.
Polyethylene sheeting under concrete slab under slab vapor retarders play a very important role in retarding moisture from coming up through the concrete and into the structure.
This is something that you could use on a yearly basis it could be anchored somewhere to swim from or it can be used to float down the river or acoss a lake.
Secure the garbage bags with duct tape.
Form two sausage shaped floaters.
Food water edit edit source empty cup 4 empty bottle 6 simple purifier 4 advanced purifier 6 cooking pot 6 sprinkler 12 scarecrow 3.
This is a good choice as the cost is minimal and the holes can be easily made or enlarged to accommodate your plants.
Then a waterproof plastic sheet is laid over the earth and a thin layer of plain cement concrete pcc is poured just to create a perfectly flat and level base for the foundation.
Polystyrene sheets these are cheap to buy and surprisingly effective in your floating raft system.
After this a waterproofing layer is installed if it is a basement.