So you've just had a beautiful concrete project installed and winter is coming fast. You are probably wondering if the things you have heard about concrete damage from winter elements are true. We we are here to help. The following is a short list of thoughts and procedures that may help you decide how you will maintain your concrete this winter. As we all know, winters in Indiana can be brutal.
Concrete in its hardened state is a very rigid and porous structure. On a microscopic level, you concrete would almost look just like a sponge. Exterior concrete is mixed and poured with an air entrainment additive to create millions of tiny air pockets within the structure to allow for moisture to find a place to settle, freeze and expand, with less chance of popping the surface off. When concrete is poured without an air entrained additive in exterior elements, the moisture in the concrete has no place to expand and will almost certainly de-laminate the surface.
Air entrainment is not a sure fire way to prevent damage from freeze thaw cycles. Concrete sealer is applied to almost every one of our exterior projects to act as a barrier protecting the concrete from the elements. There are many different types of sealer, almost all which perform the same task, but also wear rather quickly. Concrete sealer applied on an annual or biannual schedule is recommended to maintain the color and life of the surface of the concrete. This is another big step in the right direction for preventing damage from freezing ice and snow. Typical sealers will not protect from scratching or cracking. Be weary of any items that may scratch or score the surface of your concrete.
Now lets get to the point. We recommend against any use of any material that will melt snow and ice at below freezing temperature. Crazy right? Well here is the science. Any time you melt snow, ice, or moisture when the ambient temperature is below freezing, the melted moisture penetrates deeper into the concrete rather than evaporating in most cases. Once it penetrates deeper, it has a higher likelihood of freezing, expanding, and popping the surface off of the concrete. Concrete sealer and air additives can only do so much to prevent this damage but it will happen on a larger than normal scale once salts and de-icers are added to the equation.
Replacement of de-icers: We recommend folks use kitty litter or sand as a means of adding safe tractionable areas to their exterior concrete in high traffic areas. In the spring this can be swept or blown away and is very little mess. The best defense is a good offense. Sweep, blow, shovel, plow, or snow-blow, any snow off before it gets packed down by cars or foot traffic and you will be in excellent shape. Packed snow from driving or walking on fresh snowfall is probably the number one cause of ice formation.
Springtime checklist: Now that you've made it through winter, take a look around on the concrete and note any sever pop-outs or cracks that should be filled. Severe scaling or popping is defined as de-lamination of more than 25% of the surface area in a given area. Severe cracking or sinking is defined as any crack developing over 1/4" wide within the first year of use, or any concrete that has sank, settled, or risen more than 1" permanently. Concrete will naturally expand and contract with warm and cold temperatures and can actually move up and down and side to side up to 1"-2" between winter and summer. Concrete that has risen in the winter will usually settle back to its original position in spring. Concrete is expected to crack within the first 30 days of its life (hopefully within the control joints) but if a crack should occur outside of a control joint and widen to more than 1/4", call us so we can caulk and seal the crack. Spalling, scaling, or pop-outs can usually not be repaired and should be sealed rigorously as soon as temperatures allow. You can seal you own concrete with a basic "water base masonry waterproofer" from any big box store with a pump up sprayer so long as the surface is relatively clean and free of standing debris.
Please call with any questions or help with any of this! Happy Holidays!