Not surprisingly the number one most consumed substance on Earth is water. You might be a little surprised to learn the second most widely used substance is concrete. That’s right, according to the Pacific Southwest Concrete Alliance the concrete is the second most used material on the planet.
You might think concrete is a responsible choice for the eco-conscious consumer. After all, it is made up of little more than cement, sand, gravel, and water. That sounds like a harmless enough combination, right? Not quite. Cement is extremely energy intensive to produce. It requires incredible amounts of energy, and it also releases a large amount of CO2 (a harmful greenhouse gas) into the atmosphere.
Fortunately, there are several “green” alternatives to traditional cement and concrete. Read our article on eco-friendly concrete to learn more.
We hope you can use some of this information with your new garage plans to make your garage building project a little more eco-friendly.
When is the best time of the year to build your new garage? That depends on several factors, of course. The most restrictive part of your garage building effort is probably going to be the concrete that you use for your footings, foundation and parking slab. Concrete has particular curing conditions that will give you optimal results. According to the Portland Cement Association (PCA, www.cement.org, who would know better than an organization with cement in their url?) the best conditions for curing concrete are to keep its temperature between 50 and 75 degrees Fahrenheit (or about 10 and 24 degrees Celsius). When the temperature gets too hot the water in the concrete evaporates too quickly causing a poorer quality concrete. If the temperature drops below 50 degrees F during the curing period the hydration process slows down and your concrete stops gaining strength. A proper job of curing your concrete will improve its durability, strength and resistance to temperature extremes. You are also trying to keep the freshly poured concrete from drying out too rapidly. This can be helped by keeping a steady source of water on the concrete as it cures or covering it with plastic to reduce evaporation. The curing period generally takes about 5 to 7 days from the time you pour your concrete.
The PCA also tells us to expect some cracking to occur in the concrete because it does shrink a little as it dries. Expect about 1/16th of an inch shrinkage for every 10 feet of concrete poured. Your concrete contractor will know this and how to compensate for it so your slab doesn't end up looking like a desert lake bed during a drought. When you hear the concrete guys talking about a five sack (or bag) mix, they are talking about how many bags of portland cement are used to make a cubic yard of concrete. The PCA suggests that a good rule of thumb for quality concrete is to make sure your contractor (or you if you're doing it yourself) uses a six bag mix, or six bags of Portland cement per cubic yard of concrete. Other sources recommend a 5 or 5 1/2 sack mix, so it's probably a good idea to consult with your local concrete supplier. A sack of Portland cement (not the pre-mix concrete you might buy at your local Home Depot or Lowes) usually weighs about 94 lbs.
You've no doubt seen finished concrete surfaces that have flaked, or spalled. This can be caused by
freezing and thawing of the concrete
excess water in the mix
finishing before excess surface water is gone
There is a type of Portland cement called air-entrained that contains microscopic air pockets which can reduce the effects of flaking due to the freezing cycle. Other additives can also be added to the concrete mixture to have the same effect. Ask your concrete supplier.
So there you have it, temperature is going to be the driving force behind your garage building schedule. Concrete pouring and curing are the most restrictive elements of the project. For most areas that means you are going to have your best luck with your garage building project during the spring and fall seasons. We'll discuss some other driving forces in your project in future posts.