Top dressing your lawn can be beneficial in many ways.

It is used to help with surface drainage by way of encouraging a new soil profile.It will as create a lower crown lever (Fig 1) which will create a stronger grass plant.

A Silica Sand is used for this treatment (Fig 2) and can be applied all year round using a walk behind spreader. This treatment will also help with surface drainage on your lawn as it will allow water through the soil quicker. Regular dressing will create an even surface on your lawn.

It is also extremely important to top dress after aeration to fill in the aeration holes.

Fig 1

Fig 2