There are three main methods for installing wood floors. Which one is suitable depends on the type of flooring you are laying i.e. solid wood, engineered wood or laminate and also on the type of sub-floor that it is to be layed upon. There follows a description of each method with explanations as to when that method would be appropriate.
The nail down or staple down method is probably the most demanding of methods, requires the most skill and potentially specialist tools such as a floor nailer and so, is usually carried out by a qualified flooring fitter or installer.
This method can only be carried out when there is a wooden sub-floors as obviously you wouldn't be able to nail into concrete, at least, it's not advisable. Nailed down installations are most commonly used with solid wood floors as due to their extra thickness plus the fact that they will be more prone to expansion, contraction and movement they tend not to work too successfully with the glue down method. The nail or staple down method can be used with engineered wood floors however, because engineered wood floors can be very successfully installed with the glue down method which is quicker and thus cheaper, this is usually the method that will be selected. It is not a method that's suitable for laminate flooring.
If a nailed or stapled down installation is to be over a wooden sub-floor of floorboards, the planks should be laid in the opposing direction of the floorboards. This ensures far greater stability to the laid floor. If however, the sub-floor is of a plywood construction the flooring can be laid in any direction which, tends to be in line towards any light source such as a window. It is also recommended to use a poly-foam underlay beneath the flooring which should eliminate any squeaking whilst also providing a bit of thermal and sound insulation.
As with any installation method, the condition and preparation of the sub-floor is absolutely key to sound, stable and successful installation using the glue down down method. The glue down method, as the name suggests, involves using specialist adhesives or bonding agents to fix the boards to the sub-floor. This method can be used over either wooden sub-floors or concrete sub-floors however, if it is to be used over a concrete/cement sub-floor, it will be necessary to first lay a two part damp proof membrane. This not only prevents any moisture getting into your flooring from the sub-floor but also provides a suitable surface for the adhesive to bond to. Always be sure to refer to the manufacturer's instructions and recommendations as to which adhesive to use as there are different kinds for different applications. The glue down method is suitable for both engineered wood floors and solid floors but is not recommended for laminate wood floors.
The floating installation method is the easiest of all the methods and the most suitable if you are a keen DIYer and thinking of doing it yourself though you will still need to be able to measure and cut accurately. Instead of fixing the flooring to the sub-floor as with the other methods, the boards are fixed to each other. This is achieved either by using a PVA adhesive in the groove of a tongue and grooved system or, in the case of clic-lock systems of which there are a clic-lock systems , the boards lock together without the need for additional adhesive. This means that when the floor expands, usually during the summer months, the whole floor expands as one unit. An expansion gap is left around the perimeter of the room plus any other immovable objects to account for this as is the case with any of the installation methods.
The floating method is most ideally suited to laminate flooring though can also be successfully employed with engineered wood floors. It is not a recommended method for installing a solid hardwood floor.