When working in hot weather, it is important to consider four key temperatures: water, powder, air and surface. Higher temperatures for any of these can reduce a grout’s working time, especially for fast-setting products.
Here are best practices to help ensure successful grouting in the heat of summer.
1. Ensure the powder temperature is between 60 F and 80 F (16 C and 27 C) prior to mixing. Store bags in a shaded or conditioned space, if possible. Powder generally makes up between 78 and 86 per cent of the final weight, which means hot powder will lead to a short working time, even if it is mixed with cool water.
2. When possible, plan the job to avoid the hottest part of the day and sun exposure. Ideally, start early in the morning and use shades to cover the installation. If an area cannot be shaded, try to complete the installation during the coolest part of the day.
3. Be cognizant of the water temperature. If necessary, add ice to cool the water. Cool water and cool powder can greatly extend working time in hot conditions.
4. If reusing buckets, be sure to clean any residual product out of them before starting the mix. Cross-contaminating grout with other cement-based products can shorten working time.
5. Always add the grout to the water before mixing with a low-speed drill. A speed of 300 to 500 revolutions per minute is recommended for grout and mortar installations. Allow the grout to slake before remixing. Be careful not to over mix the grout.
6. Mixing at the high end of the water amount will extend pot life. Be sure not to exceed the maximum.
7. Pre-moisten the tile before grouting. This will help keep the tile cool and extend working time. Do not install grout on tile that is hot to the touch.
8. Work in small areas to ensure easy clean up. Be sure to use the grout float to remove as much excess grout as possible from the surface of the tile as you work through the installation.
9. If the grout begins to set up, it can be gently remixed to a groutable consistency. Do not add additional water.
10. Start the cleanup process as soon as your finger comes away with no transfer after lightly tapping the grout joint. The time it takes for the grout to firm up in the joint can be drastically shortened in hot weather, so it is important to check the grout’s readiness for cleanup earlier. Be sure no haze remains on the tile afterwards.
Heather Ruhl is the training program manager for H.B. Fuller construction products. Heather specializes in ceramic and porcelain tile installation techniques, surface preparation and adhesives. Before taking on her current position, she spent three years as a technical representative with TEC, offering technical support, on-site training and troubleshooting.