Making a caupona or other structure for events

[Musivarius]

One thing you might like to consider for any future projects instead of using plywood are the baseboards using in tiling work. These have that advantage of not being affected by water in the same way as ply but also they're a lot lighter. There are 2 types;
Cement fibre board - Hardibacker, No More Ply. heavier board usually in 6mm and 12mm.
Compressed foam board - Marmox, Shluter Kerdi board, Wedi. Lightweight and come in 6mm to 25mm. Marmox is about the cheapest (about £10 for a 1200mm x 600mm sheet). They can be cut with a stanley knife. Used for tiling onto for walls, if you wanted to make things like a lararium then this would be ideal.
it's worth looking around as there are a lot of these things being developed now.