Warm weather can ruin flooring products faster than cold, making correct storage and handling absolutely essential onsite, says David Powell
WE spend a lot of time talking about cold weather and the problems it causes with flooring products. Cold slows everything down – curing, drying, tack development – and most experienced installers have learned to plan around it. But warm weather can be just as detrimental.
The good news is that it’s easy to manage, and most of the time it comes down to storage. Get that right and you won’t have any issues.
Your van is the biggest risk
If there’s one thing to take away from this article, it’s this: get your products out of the van. Vehicles act like greenhouses. Sunlight comes through the glass, heats up the interior surfaces, and that heat gets trapped. On a warm day, the temperature inside a closed van can climb well above what it is outside, and with no airflow, it just sits there.
People often think leaving products in the van overnight isn’t a problem because it cools down at night. But in summer, daylight hours are long, and by the time the temperature drops, those products have already spent most of the day soaking up heat. Smoothing compound powders are the worst for this.
Because of their bulk density, once they’re warm, they stay warm — bags that have been in a hot van can hold that elevated temperature for days, even after you move them somewhere cooler. When you come to mix them, that stored heat speeds up the reaction and the compound stiffens up too quickly to work with properly.
The fix is simple. Unload your products into a cool, sheltered spot on-site as early as you can. It’s not glamorous advice, but it’s the single most effective thing you can do.
What heat does to your liquids
Different products react to heat in different ways, but none of them react well.
Epoxy-based products – typically your high-performance surface DPMs – are two-component systems that start curing the moment the parts are mixed together. If those components are already warm when you mix them (25deg C and above), the reaction speeds up significantly. You’ll notice the product thickening in the bucket much sooner than expected, which cuts your working time and makes it much harder to get a consistent, even film on the floor.
Water-based primers and DPMs go the other way. They become thinner and runnier, which makes it hard to build up the film thickness you need. And film thickness is everything with these products. If you’re applying them too thin, they’re simply not going to do their job.
Adhesives get hit on two fronts. When a water-based adhesive is too warm it loses body and won’t fill the V-notch on your trowel properly, so you end up with insufficient adhesive on the floor to form a reliable bond. On top of that, the water in them evaporates much faster in the heat, which dramatically shortens the open time. An adhesive that gives you a comfortable working window at 20deg C can become very difficult to lay into at 30deg C.
Keep all liquid products out of direct sunlight wherever you can. If you’re struggling to keep them cool enough
on-site, try standing the sealed containers in a bucket of cold water before you need them. It’s not a perfect solution, but it’ll bring the temperature down enough to buy you back some working time.
Check your adhesives before you start
Here’s one that catches people out. Acrylic adhesives, even in sealed buckets, can eject water to the surface when they’ve been stored in warm conditions. Open the lid and you’ll find a layer of liquid sitting on top. It doesn’t mean the product is ruined, but you do need to give it a thorough stir before you use it to get that moisture back in and restore a consistent texture. If you skip that step, you’re asking for an inconsistent bond.
Remember what the data sheet assumes
Every open time, working time and curing time on a technical data sheet is based on what we call ‘room temperature’ – typically 20–23deg C. That’s not a rough guide. It’s the baseline that every stated performance figure is built around. Go significantly above it and curing accelerates, open times shorten, and working windows shrink.
You can work in smaller areas to stay within reduced open times on a hot day, and that does help. But it’s a workaround, not a fix. The real answer is to manage your storage so that products are as close to that 20–23deg C range as possible when you come to use them. Look after your products and they’ll look after you on-site.
www.bostik-profloor.co.uk
David Powell is technical consultant, Bostik UK
