That depends.

Usually if the wall is "squalado" palitada or wall finishing should be minimal. Thickness may vary from 1/2 to 1 inch. This would be rough finish, followed by a smooth finish (surface ready for painting).

For the size given, its more convenient to order materials by bulk, like 1 elf of sand, and 25 bags of cement. Pag hindi lahat nagamit ang cemento, you can still use it for smooth finishing. Take note that it could take more materials, so its best if you have it estimated by a mason.

I also suggest you mix "sahara" or "morta-seal" into your palitada mix. These will act as waterproofing agents on the wall exposed to the elements.