Since it is only the surface of the floor which takes the abrasion and the wear, it seems pointless in most instances to produce a floor which contains solid resin throughout, and some element of doping is acceptable.

The agents used for doping vary from Industrial Talcum Powder, to a variety of sands, on to granite, gravel, and heavier aggregates, and the proportion of resin to filler is critical to the eventual performance of the floor.

The addition of too much filler will produce a screed which is depleted of resin, is internally honey-combed, and exhibits high absorbency. These characteristics are all typical of poor quality floors, and negate the very reasons for using resin in the first place!

The temptation to exceed acceptable dosing levels is fuelled by two main factors.

Firstly it is a means of reducing system prices and thus sell more product, and secondly it generates more profit for the contractor.

The absorbency of a highly filled system can be eliminated at the surface by the application of one or two roller-coats of neat resin. This will indeed sink into the surface and strengthen it, but once the floor has been scratched, or simply cracks, then the weak interior is opened up to serious contamination.

The lack of resin within the system makes it vulnerable and swift disintegration is sure to follow.

Although a new floor may look acceptable, it is not usually possible to determine the quality of a screed by visual inspection after it has been laid.

One of the best ways to ensure that you are buying a good quality floor is to ask the question of the contractor "What is the filler to binder ratio of your screed?"

Obviously the lower this ration then the better the quality of the screed. Most contractors will be purchasing branded product and will need to refer to the manufacturers.

A typical ratio for a wearing screed would be 8 or 9 parts filler to 1 part binder, anything more than this is over-extending the resin, though such are the qualities of most resins that even filled at 11:1 it could be used as a bulked material to form falls prior to overlay with a resin-rich floor screed.

This is an accepted practice where reduced contract time is required

A heavily filled resin screed will enable the flooring contractor to create the falls required, and then top it off immediately since there is complete compatability between base and topping.

This cannot be achieved by the use of cementitious systems because of the water content of the screed, and the floor will either need a DPM on the surface, or a few days of drying, before a resin screed can be applied.

In these instances the reduced price of the sub-floor system can cause expensive delays to project completion, and thus turn out to be the dearer option for the client.