Tips for using repair mortars in cold weather

Cold temperatures can significantly impact the performance of repair mortars. As a result, one needs to be acutely familiar with how lower ambient and substrate temperatures (like cold weather) can negatively affect product performance.

As published in our products’ Technical Data Sheets, the lowest allowable installation temperature for cement-based repair mortars is generally 45°F (7°C). These are some of the recommended precautions and tips for cold-weather installations:

• Use an infrared thermometer to accurately determine the substrate and ambient temperatures.
• Never apply repair mortars over frozen or frosted surfaces.
• Use recognized methods supported by industry standards to bring substrate and ambient temperatures well above the recommended installation threshold of 45°F (7°C). 
• Use a non-chloride, liquid, accelerating admixture such as MAPEI’s Planitop Accelerator for high-early-strength and reduced setting times.

The rule of thumb for Planitop Accelerator is that when the temperature is 23°F (-5°C) and rising, two Planitop Accelerator bottles (each at 5.07 U.S. oz. or 150 mL) can be added to all the products listed in the table below. If the temperature is 32°F (0°C) and rising, only one bottle is to be added.

Please use this as a guide for recommending the proper dosage of Planitop Accelerator and, if needed, perform a test before the application. More guidance for using repair mortars in cold weather is available in our Technical Bulletin “The impact of cold weather on repair materials,” view it here.

For more information, application tips and a personalized customer service, call our Technical Services line at 1‑888‑365‑0614 or visit our Website at www.mapei.com/us.