There are two kind of defects on a rubber flooring that probably and unfortunately all wetpour (pour-in-place or PIP) installers have at some time suffered in some job site. Both effects are easy to pinpoint and a concern for the customers when occurring on the top layer.
On the next few lines I will try explain the main causes that I know about both issues that are mainly responsibility of installers and very weirdly have to do with the materials quality.
Granules crumbling or disintegration
This problem of crumbling or disintegration where granules are spreading around is one of the most frequents flaws that I’ve seen on rubber flooring during the many years I’ve been involved on rubber Safety Surfacing projects.
This problem is in near 100% of cases an installation problem, so material manufacturers have nothing to do with it and will usually do not accept any responsibility in case of a warranty claim as they have no control on the process used by the installer.
All main polyurethane binder and EPDM or TPV granules good quality manufacturers have tested cross compatibility within the most significant products with high share on the market, so for sure gluing of the granules have been fully tested in different conditions.
There are several potential causes for granules crumbling and in my past experience I only found one that could be originated by the material quality itself:
- Insufficient proportion of binder used. More than 20% is usually the recommended for top layer as some colours may need a slightly bit more than others to achieve a similar gluing performance.
- Binder used had very low viscosity for the ambient temperature at installation time and as a result binder drained down to the bottom keeping the granules dry and impairing their gluing.
- The mixer is not appropriate for wetpour requirements or mixing time was insufficient leaving some granules dry. Specialised mixers are needed for wetpour.
- The granules are dusty and the gluing becomes more difficult so a higher binder proportion will be required. This is an example originated by a dusty EPDM material.
If the crumbling is not widespread a potential solution is to apply a top coat with one of the specialised coats or using diluted polyurethane binder (be aware of yellowing effects, so use aliphatic if the original colour required it).
Foaming effect
This is a defect that I’ve also seen, especially in some of these countries with frequent rainy weather. The cause of foaming is a too high curing speed and excess reactivity due to presence of excess of water during the curing process.
There are then several potential causes for foaming:
- The granules were wet of water when mixed with the binder.
- You sprayed too much water to speed up the curing process.
- Unfortunately there was a heavy rain shortly after finishing top layer and during curing process.
- Ambient humidity was very high while using a high reactivity binder on top layer.
If you are a wetpour installer, this is my final reminder to avoid foaming: store granules bags on job site under cover from potential rain, select the appropriate binder for the expected weather conditions, don’t try to seed up the curing spraying too much water and after finishing the top layer, cover the job site in case of rain forecast.
Take care
Rubberman Blog 