It’s a very common mistake to think that the color of your cement is an aesthetic choice, or one of convenience. When it’s poured, the color is going to be exactly what the mixture wants, and it will continue to look like that forever. Just because you have green cement doesn’t mean you should have green curtains.
What’s more, you’re not limited to just one color either. In fact, as long as your building has a concrete foundation, there are three basic types of cement you can buy: colored (like yellow or brown), white (like gray or tan), and neutral (like black). And there are 12 other shades in between.*
The right color for your building depends on more than just the kind of house you want to build. It depends on its function as well: how much insulation and soundproofing you want; whether it will be visible from outside; whether it will be visible from above; how much maintenance it will need; whether it will get hot in the summer and cold in the winter.
We tend to think of the ideal house as a timeless, neutral, monolithic structure. But actually, if you’re building a new home in today’s market, you should be thinking about how to make it look good, and how to make it function well.
It’s not only that attractive houses sell faster. They also last longer and are more energy-efficient. The best houses are the ones that combine both functions.
The color of cement is just the start of what you can do to build a beautiful house – or any kind of structure. You can use a variety of other materials to give your house personality. These days people are more likely to consider color than they used to be; but there are other factors that make personality important, such as textures (carpets and textured ceilings), patterns (terracotta tiles and metal grilles) and even smells (a wood stove or composting toilet).
Cement is not a chemical. It consists mainly of the mineral calcite and limestone, with a bit of iron oxide. The main ingredients in concrete are cement, sand and water.
The mixture is made into concrete by adding lime or slaked lime, which reacts with the calcium in the limestone to form calcium chloride, which reacts with the iron oxide to produce calcium hydroxide and silica, which produces the glassy properties of glass. The silica makes up about 6 percent of a normal batch of cement.
A coloring material can be added to give your cement color. If you make your own cement at home, there are several colorants that can be added to the mix: titanium dioxide (for light-colored mortars), iron oxide (for grayish-brown mortars), manganese dioxide (for tan mortars), mica (for brown mortars), chromium oxide (for black mortars) and silicon dioxide (also called quartz sand). The most common pigment used is titanium dioxide because it is relatively nontoxic and easy to work with.
In addition to colored cement, there are completely colorless or nearly colorless products for special applications such as insulation.
Cement manufacturers are trying to seal their products, not just keep out water. If they can make a color that is as close to white as possible, they create a wall that is hard to distinguish from a painted wall. They also try to get rid of any colors that might cause people to choose another product.
So the colors you see in cement now all have a common purpose: trying to be white. They achieve this goal by adding pigment. The pigment is mixed into the cement itself, so the end user never sees it; he only sees the color of the finished product. All the colors have roughly the same amount of pigment added, but some colors have more than others. The more pigment, the whiter the color will look.
It’s somewhat like trying to make your skin whiter by adding soap flakes. The problem with soap flakes is that if you use too much soap flakes, your skin will start looking yellowish and greasy. But if you use enough, you can get a really smooth surface and almost no soap residue left on your skin or in your bathtub.
To make colored cement whiter, you need an even balance of pigment and cement powder; if there’s too much pigment and not enough powder, the cement will look stained
Cement is made by reacting calcium with oxygen. The color of the resulting mixture comes from something that is a chemical process, and not at all a pigment. If you want to make colored cement, you have to have a different chemical process that adds pigments to calcium instead of oxygen.
The chemistry of coloring cement isn’t complicated. But it’s not simple either. In fact, it’s really hard to make colored cement, because it’s hard to get the mixing just right so that when the reaction is completed, the pigments are evenly distributed throughout the mixture without causing clumping or filaments. Once you get it right, it stays right.
Color is very important in architecture. It’s one of the things that make a house special. There are many reasons for that:
First, color is a good way to make a house feel warmer or cooler. Usually, you want your house to feel warm; people put fireplaces in their homes because they like it warm inside. But the kind of wood you use matters; redwood is not the same as redwood. So too with color.
Second, color makes a big difference in materials and appearance.
You can’t build a green house out of simple concrete blocks, but you can build a green house out of glass and steel and plastic. That’s because green houses are usually made of different materials than ordinary houses: windows, roofing, insulation, and so on. Sometimes the materials used to make a design or to decorate or insulate a building can be as expensive as the design itself; sometimes not. The materials used will depend on how important color is for your particular design.
Color also makes a big difference in cost. The color of an ordinary concrete block wall is black, yellow or gray; it’s just concrete pigment in the mix without any special treatment to change its color. If you add some colored cement to it, though,
Colored cement is made from a fairly common mineral. The pigment to make it, however, is rarely found in nature. It must be produced in a laboratory by a chemical process that involves using highly toxic chemicals and producing an intense heat. Then the pigment must be ground down and mixed with water to make colored cement.
The pigment is made of pure iron oxide (also known as rust). When iron oxidizes it turns red in color, which is why the pigment is called iron oxide or rust. It looks like the material you would use to stop water from seeping through your walls; but instead of stopping water from seeping through, it stops air from going through, eventually turning your walls into asbestos.