Tile Grout Specific Redispersible Polymer Powder: Preventing Cracking

Cracking is a common performance concern in cement-based tile grout. Redispersible polymer powder (RDP) 

can be used to modify key properties of the grout, particularly bonding strength and flexibility. 

For formulations exposed to water, waterproofing may also be an important requirement.

The right RDP should therefore be selected according to the required performance of the finished tile grout 

rather than simply choosing a general-purpose grade.

How RDP Supports Tile Grout Performance

For tile grout formulations, the main RDP-related performance requirements may include:

1) Bonding strength – important for adhesion within the grout system and to the relevant surfaces.

2) Flexibility – helps the formulation meet its required flexibility and reduce the risk associated with cracking.

3) Waterproofing – relevant when the grout formulation requires additional water-related performance.

RDP is only one component of a tile grout formulation. Cement, fillers, cellulose ether, water content, 

additives, mixing conditions, and curing conditions can also affect the final result.

How to Choose RDP for Tile Grout

A practical selection approach is:

Tile grout requirement → Required performance → RDP grade → Formulation testing

For a general tile grout formulation where bonding strength and flexibility are the main requirements, 

JINT™-502 can be evaluated. It is a high-bonding-strength RDP for dry-mix mortars, and its listed 

functions are bonding strength and flexibility. The product page also specifies tile adhesive as an application.

JINT™-503 is a universal-grade RDP for dry-mix mortars. Its listed functions are bonding strength and flexibility,

 and the product page includes tile adhesive among its applications. It can be considered when a universal-grade RDP is required.

When the tile grout formulation requires bonding strength, flexibility, and waterproofing, JINT™-745 is the

more directly relevant grade to evaluate. Its product page specifically lists joint filler as an application and identifies all three functions.

How to Test RDP in Tile Grout

Before selecting an RDP for production, compare candidate grades in the actual grout formulation.

A basic evaluation can include:

1.Bonding strength – compare the required bond performance under the relevant curing conditions.

2.Flexibility and cracking behavior – inspect the cured grout and compare cracking or failure behavior under the selected test conditions.

3.Water-related performance – test this when waterproofing is part of the product requirement.

4.Application properties – check mixing, workability, filling behavior, surface finish, and curing.

For a meaningful comparison, keep the formulation, RDP dosage, water level, mixing procedure, curing conditions, and test method consistent.

Select RDP Based on the Finished Grout

RDP selection should start with the performance requirements of the tile grout.

For bonding strength and flexibility requirements, JINT™-502 or JINT™-503 can be evaluated according to the

formulation requirements. Where bonding strength, flexibility, and waterproofing are required, JINT™-745 

provides a more direct product match based on its listed functions and joint filler application.

JINTEDIFU supplies redispersible polymer powder for dry-mix mortar applications. Contact us to discuss 

your tile grout formulation, RDP selection, and testing requirements.

Name: Molly.Wang

E-Mail:molly.wang@jtdf-rdp.

Mobile:+86 156 5045 0156（Whatsapp）