When should you use underlay beneath your Gerflor floor covering?

No smoothing out of the original floor 

Underlay will not smooth out any imperfections in the surface on which you are going to lay your floor. It will actually magnify them. Therefore, you must make sure that the surface on which you are going to lay your new PVC floor is compatible with that type of floor covering (refer to the article entitled "Can I lay a PVC floor covering on top of my ceramic tiles?")

Sound insulation for flats only

Using underlay to improve sound insulation with vinyl tiles or planks is only worth considering if you live in a flat and want to reduce the noise of your footsteps. This noise reduction would only benefit the people living on the lower floors, such as if you are trying to resolve a conflict with your neighbours. 

However, fitting underlay in a properly insulated house or flat would amplify the noise when walking across the room, since it would create a resonance chamber.

Always choose a Gerflor-approved underlay 

Not all types of underlay are the same! If you choose an underlay that is not compatible with a Gerflor floor, there is a risk that the tiles and planks could become unclipped over time. Furthermore, if you do not install a Gerflor-approved underlay and product quality problems subsequently arise due to the installation, you will not be covered by the warranty, since this is not recommended in the installation guidelines for our products.

As you can see, underlay is a solution for those who wish to reduce the noise of their footsteps. As for the rest, only minor work will make a difference!