To combat the cold, job sites fire up temporary heaters. While salamanders and propane heaters keep the crew warm and prevent freezing, they introduce a chemical risk to your concrete surface that is often overlooked until the floor fails: Carbonation.
The Chemistry of Failure
Direct-fired heaters release carbon dioxide (CO2) and moisture vapor as combustion byproducts. When high concentrations of CO2 interact with the calcium hydroxide in fresh concrete, a reaction occurs, creating a weak layer of calcium carbonate on the surface.
This carbonated layer is:
- Soft and Chalky: It lacks the structural integrity to hold a bond.
- Chemically High pH: It can interfere with adhesive curing.
If you install flooring over a carbonated slab, the adhesive may bond to the carbonation, but the carbonation will detach from the slab. The result is a delaminated floor, regardless of the moisture content.
Detection and Prevention
Standard moisture tests do not detect carbonation. This requires a surface analysis. As your independent diagnostic partner, IFTI technicians are trained to look for environmental red flags like unvented heaters.
We recommend:
- Using indirect-fired heaters that vent exhaust outside.
- Conducting surface tensile strength testing if carbonation is suspected.
- Grinding the slab surface to remove the carbonated layer before installation.
Ensure your substrate is sound. Request a comprehensive slab analysis from IFTI.
Ready to master every aspect of concrete moisture and floor preparation? Explore our full library of expert Resources to keep your projects on track.
