Skip to content
English - United States
Contact us
  • There are no suggestions because the search field is empty.

Working with Phoscrete in Cold Temperatures

Phoscrete’s Magnesium-Phosphate-Cement (MPC) repair materials are engineered for reliable performance, even in cold weather. Learn how to achieve fast, durable repairs with Phoscrete when temperatures drop below 50°F (10°C), including sub-freezing conditions.

Why Cold Weather Matters

  • Low temperatures can slow set times, make mixing harder, and affect bond strength.
  • Phoscrete F1-HC can be installed in temperatures as low as -5°F (-20°C) when best practices are followed.
  • Phoscrete F3 products are suitable for use above freezing (32°F/0°C); special care is needed below this point.

Materials & Tools Checklist

  • Phoscrete F1-HC or F3 kits (ensure “use by” dates are valid)
  • Phoscrete Fast-Set Admix (for F1 only)
  • Large insulated bucket/cooler (for warming components)
  • Hot water for warming activator jugs
  • Heavy-duty mixing drill and paddle/auger
  • Clean, dry mixing buckets (8-gallon recommended for cold work)
  • Propane torch (for drying and warming substrate)
  • PPE: gloves, eye protection, dust mask

Step-by-Step Cold Weather Installation

1. Condition Materials Before Mixing

  • Warm the Activator:
    Place sealed activator jugs in hot water until they reach room temperature.
    Do not boil or overheat.
  • Warm the Dry Mix:
    Store dry mix bags indoors before use.
  • Use Fast-Set Admix:
    Add the recommended number of scoops to the activator per the usage chart (see below).

2. Prepare the Substrate

  • Surface must be clean, dry, and sound.
  • Use a propane torch to gently “kiss” the surface to remove ice/moisture and slightly warm the concrete.
    Caution: Do not overheat—prolonged heat can degrade compressive strength.
  • Remove all slurry and dust; surface must be dry.

3. Mixing Phoscrete in Cold Weather

  • Always add activator first, then dry mix.
  • Use a heavy-duty drill and paddle/auger—mix longer in cold weather (1–2 minutes or until fully wetted).
  • Admix Usage: Refer to the Fast-Set Admix chart for the correct number of scoops per kit (see below).
  • Use a larger bucket (8-gallon) for easier mixing.

4. Placement and Finishing

  • Move quickly: Working time is short, especially with added Fast-Set.
  • Use a pencil vibrator to improve flow and finish, especially in cold conditions.
  • Place and finish in lifts for deep repairs; blend each lift well.

5. Curing and Opening to Traffic

  • Phoscrete F1-HC typically achieves traffic-ready strength in under 1 hour, even at 40°F (4°C).
  • In extreme cold, allow extra time and check set before reopening to traffic.

 

Fast-Set Admix Usage Chart (F1-HC)

Usage chart

Never exceed 10 scoops of Fast-Set per kit. Mix longer as temperature drops.

 

Pro Tips

  • Plan ahead: Pre-warm materials and have all tools ready.
  • Test a small batch: If unsure about set time, do a trial mix at the jobsite.
  • Use a propane torch to dry and slightly warm the substrate—never pour on wet or frozen surfaces.
  • Avoid pouring water directly on Phoscrete at any stage.

 

Troubleshooting in Cold Weather

Screenshot 2025-06-11 at 12.04.17 AM

Need More Help?

Contact your Phoscrete Sales Engineer or call our main office at 561-420-0595 for custom mixing guides, on-site training, or to troubleshoot a tricky job.

For more technical guidance, view our cold temperature concrete repair guideline.

You can also use the live chat on our website or fill out the contact form below