I've tried googling this and asked people at the shop where I bought all my stuff for it but besides adding more concrete to the Base in the sunken areas I can't seem to find any advice.In some areas it is sunken by a couple centimeters and in others it is completely level so I need some sort of material that can vary easily in thickness. Currently I'm using plastic wrap balled up underneath while I screw the joists together but I need something permanent for when I attach the frame to the concrete base. via /r/DIY http://ift.tt/2sy21GM
