Your Finish Is Only As Good As Your Care.
In colder climates we have issues with maintaining our hardscape surfaces. With freeze thaw cycles and different ice melting products available how do we know what is best for our concrete hardscapes?
The goal is to offer you, the client, tips for the best looking and longest lasting finish for your concrete hardscape installation.
This article describes the effects of different ice melting products and what the potential effects of these process will be on your concrete hardscapes.
There are 4 basic types of De-icing products and each will affect the concrete in different ways and will eventually cause scaling of the surface.
SODIUM CHLORIDE (ROCK SALT) is the most common de-icing product available. This is generally used by most cities and municipalities on roads and sidewalks. The watery BRINE solution created is the most corrosive and damaging of all Ice Melting options.
CALCIUM CHLORIDE is generally a white pellet product. This product was originally marketed as a safe ice melt product for concrete pavers and concrete walkways. This is the most commonly used product for Impressed Concrete. It will work in temperatures as low as -30 C.
Potassium Chloride has been developed to be safe to plants and will not irritate your skin. It is generally marketed as a Pet Friendly Ice Melting product. This combination melts more slowly than the others and will not work if the temperature drops below -10 C.
Magnesium Chloride is the newest form of De-icing product. Its composition is deemed to be the least harmful of all de-icing products. It has the highest melting point and will not work under -6 C.
DO NOT USE Ice Melting Products.
I know this is hard to fathom but products that melt ice are very bad on Concrete and Hardscape surfaces. You should not use any type of melting products on concrete surfaces for at least 12 months on new installations. If you must then you need to use as little as possible and clean off any slush or excess as soon as possible.
It is not the De-Icing product that damages the surface but the melted slush that sits on the surface of the concrete. This slush finds it’s way into the concrete pours and will then freeze causing the surface to flake off. Using a High Quality Silicate Based Penetrating Sealer will help deter this.
The length of time required to cure concrete will vary based on the weather and the Concrete Mix but is generally 28 days. After 7 days, concrete has usually reached about 65% of its full hardness. After 14 days it typically reaches about 90%, and the final 10% is around the 28-day mark.
With any concrete surface and more so with Decorative Concrete, Freeze Thaw Cycles will cause the surface to FLAKE. This FLAKING process is called Scaling. Concrete will eventually form a ROCK-HARD surface, but this is performed over time. Concrete completely sets in about 28 days but will continue to harden over the following months. During this time, it is important to protect the surface so that you do not see the scaling.
Using De-Icing products creates a FALSE Environment of Freeze-Thaw cycles. Potentially hundreds per day. These cycles can force water into the surface of the concrete causing scaling.
Some contractors have written in their contracts and clearly advise their customers of the dangers of using these de-icing chemicals to the concrete surface. This education will help prevent damage, call backs and result in a better-looking job and less callback’s.