Surface Maintenance - Surface Binder
Applying Polyurethane Binders to Macadam
Surface Binding for Macadam Courts
Macadam contains Bitumen Binder, the purpose of which is to bind the stone aggregate together.
On older macadam surfaces, the original bitumen binder incorporated into the macadam mix will age and eventually weaken.
With the progress of time, the surface begins to fret, resulting in areas of loose stone and noticeable wear, gradually leading to areas of complete surface breakdown.
Surface Binders are clear coatings that are applied to new or old macadam surfaces to provide enhanced strength to the playing surface. Binders are available in either water or solvent based acrylic or polyurethane formulations and are spray applied.
Binders also aid the adhesion of the paint coating to the macadam surface, acting as a form of tack coat.
The life of Tennis & Sports Courts Macadam Surfaces and their paint coatings are normally inter-dependent and are usually affected by the same environmental factors.
Uses for Surface Binder
- Close to trees – the binders will help resist the effects of tree sap and bird droppings on the court surface.
- High levels of use or where non-tennis shoes are likely to be worn.
- Prolonged periods of shade leading to damp areas.
- Used by wheelchair players.
- On older macadam surfaces, where the original bitumen binder incorporated in the macadam mix has aged and started to noticeably weaken, the application of a binder coat may prolong the life of the macadam surface.
Surface Binder Constraints
Binders do not have any form of texturing agent in their formulation the resulting film coating will be slippery when wet or damp.
Therefore, if a binder coat is applied a court must also be colour coated in order to provide grip.
Applying a binder will not improve the appearance of the macadam surface. Heavily pitted macadam will still be heavily pitted following application. However, the surface will be stabilised against any further loss of stone.
Rule of Thumb
If an Old Macadam Court is Fretting to the extent that it is likely to break-up during power washing. The level of deterioration is realistically so great that an application of binder will not be effective. – Resurfacing will probably be required.
In addition, on very weak macadam, the quantity of binder required to hold the surface together may be such that it seals or partly seals the surface resulting in a significant loss in porosity.