Mapei PlaniLevel™ 420 is a high-strength, calcium-aluminate-based self-leveling underlayment and repair mix designed to repair or refurbish interior concrete and engineer-approved floors before traditional floor coverings are installed.
It flows easily for placement and leveling and is ready for tile in 24 hours. Light foot traffic is possible after about 4 to 5 hours. For fills of 1" to 5", clean non-reactive pea gravel can be pre-placed or mixed in, per the data sheet.
All substrates must be primed with the appropriate Mapei primer before the underlayment is applied.