The short answer is no, vinyl floors themselves don't necessarily need a subfloor. However, you may need one depending on the acoustical requirements of the building. If you are going to place the PVP on an existing vinyl floor with cushion backrest or on a tile floor below floor level, you won't need to use a subfloor. But if you're covering existing hardwood floors, vinyl floors that aren't padded, or concrete floors, then you'll want to use one.
QuietWalk Luxury Vinyl is the base you'll want to use for your application. It has a moisture emission protection of 6 pounds per 1000 square feet per day. If your concrete subfloor emits less than 6 pounds, you won't need to install any additional 6 thousand vapor barriers. If it weighs more than 5 pounds, you'll need to install an additional moisture barrier, such as Moisture Block.
Performing a calcium chloride test will determine the amount of moisture that the concrete subfloor emits. The key to installing luxury vinyl on concrete is to make sure the floor is level and clean. The bottom layer isn't necessary, but it can add noise-reducing qualities or extra softness to the product. For that reason, the preferred base for vinyl floors of this type is foam (or something else that can fill the space).
The subfloor can also help cover some imperfections that the existing floor may have, but it can only go so far. It is possible to combine the subfloor with underfloor heating, but you will have to check with the manufacturer. For example, the lack of subfloor may cause the floor to not work well or to not last as long as it should. Choosing the best subfloor for vinyl floors depends entirely on a lot of different factors, some of which aren't so obvious. Advances in 3D printing and printing techniques have made current vinyl plank brands virtually indistinguishable from pre-finished wood floors, which is why many people buy them as an alternative for everything from pine floors to teak floors and much more.
In general, moisture won't be a problem, but a lower layer will help make the new floor soundproof and, at the same time, provide an additional layer of cushioning. The floor is made up of several parts, including the joists, the subfloor, the subfloor and the floor finishing material. The type of subfloor you should use depends on the subfloor and whether it is concrete, plywood, or an existing floor material. Most homeowners who skip the recommended lower layer tend to end up regretting it because the floor usually emits a “applause” sound. The only time you don't need to install a subfloor is if there is already a pad attached to the LVP floor you purchased. The subfloor performs several functions, such as dampening sound, softening the feel of the floor underfoot, and can also act as a moisture barrier.
It's important to consider all these factors when deciding whether or not you need an underlayment for your vinyl flooring.
