In this section, we'll discuss the main products used in hard underlays - hardboard, medium density fibreboard (MDF), fibre cement and plywood.

As we look at each product, you'll probably realise that in most cases the same type of material is available in a wide range of thicknesses and sheet sizes in building supply yards.

This is because these materials are used widely in wall cladding, cabinets, doors and other building applications.

However, when it comes to using them as hard underlays, you should always select the specific product line that's designed to be used as an underlay.

And when you choose between the different products, you need to take into account the site-specific conditions of the actual installation you're carrying out, including the likely exposure to moisture, the adhesive you plan to use and the surface condition and make-up of the existing subfloor.

This means that you should only ever use underlay products recommended by the manufacturer for that type of installation - or if you do want to use a different product, check with the manufacturer first to make sure it will be compatible with the other elements of the job.