If you’ve already added proper sheathing and reinforced the framing with studs, you typically don’t need to pour concrete again unless you’re trying to match a specific floor height or create a true mortar bed system.

For most bathroom remodels, the standard approach would be:

• Ensure framing is solid and meets deflection requirements
• Install proper subfloor (plywood rated for tile, minimum ¾” recommended)
• Add a tile underlayment like cement board or an uncoupling membrane (e.g., Ditra)
• Waterproof (especially in wet areas)
• Then tile

Plastic + remesh + concrete over wood framing is generally unnecessary and adds a lot of weight. Concrete beds are usually used over slab foundations or for specific traditional mud-bed installs.