Radiant Heat and Concrete – Why proper curing is so important
To stop concrete from cracking, the first thing to understand about concrete is that it reacts to moisture. The moisture within it creates a chemical reaction that hardens the concrete.
Many people believe that once concrete appears lighter in color, with a hard surface that it is dry, but in reality concrete takes at least seven days to cure and several weeks to completely dry.
For concrete to become strong and for the surface to wear well, curing concrete needs moisture. Concrete needs to dry out at a slow continuous pace; otherwise shrinking and cracking will likely occur.
The strength of concrete when accurately cured is about 80 to 100 per cent higher than concrete, that hasn’t been cured at all. To increase concrete’s strength this curing process should be stable and continuous. If concrete becomes too wet or too dry, cracks will certainly develop, resulting in future flooring problems.
Which means that if you are curing concrete on a hot sunny day, the chemicals within concrete will stop reacting once sufficient moisture is gone – leaving it in a weakened state. Therefore concrete should be protected from damaging effects such as wind, sun and inconsistent weather.
The ideal temperature for hydration is 23°C. It is best to keep the temperature as close as possible to that level, as curing takes place.
To keep in moisture and slow down the drying process, a membrane can be used.
But there are many types of membranes on the market, and you will want to make sure the one you select is right for the type of flooring you are planning to install.
There are a variety of chemical and liquid membranes on the market, which are growing in popularity. You can apply them easily by hand or with a power sprayer and are classified under the four following base types: chlorinated-rubber, resin, water, and PVA.
Another way to prevent moisture from evaporating is to use a waterproof building paper or plastic film. Plastic sheeting is a flexible and easy covering for complex shapes. Plastic sheeting can be pulled back quickly to allow you to check the concrete over the course of curing.
Another idea is to get a spray atomizer and spray water on the concrete’s surface prior to putting on the plastic sheeting. Using a finer mist spray almost like a fog, works very well also.
Using an absorptive medium like sand or canvas is also an effective way to retain moisture.
To sum it up, if you are pouring concrete you should create an optimal environment so it can cure properly. As your concrete hardens and starts to get rid of excess water, it will shrink.
For a trouble free installation, being proactive and implementing preventative measures during curing will result in strong concrete that won’t crack.
The advantage of an installation that carefully controls moisture levels and temperatures is immense and something that should not be ignored.