Here's what to keep in mind when fitting tiles during a heatwave  

Screed

When temperatures rise above 25 °C, screed can dry out much faster than expected. This can cause the top layer to “burn”. The water evaporates too quickly, leaving insufficient moisture for a proper chemical reaction with the cement, which compromises binding.  

Tips:

• Lightly spray the screed with water in the first hours after laying, using a plant sprayer.  
• Create as much shade as possible.  
• Do not cover the screed, as this will only slow down the drying process.  
• If the screed has burned and binding has failed, replace the top layer with at least 5 cm of new screed.  

Tile glue

Hot conditions significantly shorten the “open time” of tile adhesive – the window in which tiles can be placed after applying glue. Direct sunlight, hot winds, high temperatures or a highly absorbent substrate can reduce this to just a few minutes.  

Tips:

• Always check that the glue is still wet and hasn’t formed a skin.  
• If in doubt, remove the glue and remix.  
• Never add extra water, as this weakens adhesion.  
• Work in shade wherever possible, even early in the day, since tiles can heat up and cause the glue to burn and fail later.  

Grout

High temperatures can cause grout to lose too much moisture, making it crumbly or powdery and reducing adhesion.  

Tips:

• Use fast-setting grout.  
• Work early in the morning when temperatures are lower.  
• Provide extra shade and lightly mist the joints with a plant sprayer.  
• Don’t cover freshly grouted joints.  
• Avoid grouting in the evening: even if the tiles feel cool, the substrate may still hold residual heat. Test this by pouring water on the tiles — if it warms up immediately, the substrate is still too hot. 

Key takeaway

During hot weather, screed, glue and grout all dry faster than usual and require extra care. Work during the coolest parts of the day, use shade, and lightly moisten when necessary. These steps help ensure strong adhesion and a long-lasting tiled floor.