Grout retention or grout staining is a specific concern to end users. An installation that experiences grout staining is often expensive to fix. Currently ASTM does not have an adequate test method to evaluate this issue. Causes of unacceptable grout retention can include (but are not limited to): tile manufacturing issues, grout manufacturing issues, and/or installation issues. It is acceptable for some products to retain a small amount of grout. Therefore not all grout retention is detrimental. It is necessary to evaluate each system on a case by case basis. Grout retention characteristics are a function of the materials being used and installation practices. The industry needs a method to differentiate this criteria and troubleshoot issues. This method also provides a tool for installers to utilize prior to installation to determine if a specific tile-grout system is viable.
The title and scope are in draft form and are under development within this ASTM Committee.