The decision is completely subjective, but there are some characteristics related to the two types of flooring that can help you choose. The underlayment has a shorter shutter speed, it is walkable after just 24 hours, but after the massive installation must be sanded and finished on site (an advantage when you request a custom finish, detail) operations which take about thirty days . The prefinished has a greater dimensional stability; due to the phenolic birch, plywood and you may have maximum sizes higher than in the solid. The underlayment is also recommended for installation on heated screeds and / or cooling in the floor and in the event of restructuring of existing floors, places where the laying of the massif could give you some problems if you do not take the right precautions. Those who want to recreate an environment characterized by an antique flavor, choosing a completely natural material (no glue, 100% noble wood), require the massive.