Self-leveling mortar for radiant floor heating with low flowability
Madrid, Spain
“The change was immediate. We were able to work faster, achieve a better finish, and avoid having to adjust the consistency by adding water on site.”
A company that installs underfloor heating systems contacted QUIMACER while working on a residential development of 40 homes in Madrid.
The project required pouring self-leveling mortar over multilayer piping systems, involving large areas and the need to maintain a steady pace of work.
The mortar initially used contained a conventional plasticizer, and the water content was adjusted on site to compensate for loss of flowability.
The initial pours revealed differences in behavior between the different mixes, especially on days with fluctuating temperatures and longer-than-expected waiting times.
The construction management team sought to maintain the quality of the finish, ensure proper pipe insulation, and prevent future problems related to cracking or poor heat transfer.
Problems Identified
- Rapid loss of fluidity after kneading.
- Water must be added on site to maintain workability.
- Poor pipe insulation in some areas, with a risk of pockets or gaps.
- The appearance of microcracks due to excess water and shrinkage.
- Risk of reduced thermal conductivity due to poor compaction of the mortar around the pipe.
Our Intervention
- QUIMACER reviewed the mortar system, water-to-cement ratio, mixing method, required open time, and coating thickness.
- A rheological problem was identified: the mortar needed to be more fluid without adding water, while maintaining cohesion and stability.
- It was recommended to replace the standard plasticizer with a specific additive for underfloor heating mortar.
- On-site tests were conducted using a staggered mix design to determine the optimal balance between workability, stability, and open time.
- The following practical tests were specified: mortar spread, consistency after 20–30 minutes, surface finish, and absence of segregation.
Solution Implemented
- Addition of QUIMAFLUX SR-10 as an additive for self-leveling mortar in underfloor heating systems.
- Recommended dosage: 0.5–1.0% of the cement weight, adjusted according to the type of cement, aggregate, and application temperature.
- Controlled reduction of the mixing water while maintaining application fluidity.
- Improved self-leveling properties and uniform coating of the pipe.
Target parameters: high workability without segregation, sufficient open time, and reduced shrinkage due to lower water content.
Results and Improvements
An increase in flowability of more than 35% compared to the initial formulation.
Reduction of mixing water by more than 20% while maintaining workability.
Better pipe coating and a more uniform surface finish.
Repair of microcracks observed in the first sections.
Approximately 30% reduction in application time due to improved pumpability and spreadability.
| Parameter | Technical Details |
|---|---|
| Sector | Underfloor heating / residential construction |
| Application | Self-leveling mortar |
| Project | 40 homes |
| Problem | Low flow and excess water |
| QC Product | QUIMAFLUX SR-10 |
| Recommended dosage | 0.5–1.0% of the cement weight |
| Key Improvement | +35% flow; -20% water; -30% application time |
WHY QUIMACER?
- Knowledge of technical mortar formulations.
- Simultaneous improvement in fluidity, strength, and thermal efficiency.
- A practical solution for installers and applicators.
- It reduces future problems and post-construction claims.
