Redoing a kitchen or bathroom with concrete countertops is a home improvement project you can do yourself. While it takes some time — be prepared to spread the work out over several weekends because of the time required for curing — you will save yourself the high cost of purchased granite or marble countertops.
This tutorial will provide all the information you need for planning, creating your own forms and molds, making joints, and distributing the poured concrete. I figured all of this out because I wanted to redo the kitchen in my 1916 Foursquare and I was bored with all the countertop options. (Unless you're getting formica, they all cost about the same as granite or marble, look just like granite or marble, and are as typically typical as granite or marble.) The one material I found that was much more customizable than the other solid surfaces was concrete. Concrete’s colors and textures are endless, you can mold it into just about any shape you can imagine, and it retains the advantages of solid surfaces. But it's concrete, so it must be cheaper than milled stone, right? Not so. If you have a professional do it for you, it can actually cost MORE than other solid surfaces. Do it yourself and you can save a bundle. I priced granite countertops for my kitchen and they came out at around $4,000. My custom concrete countertops ended up coming in at below $800, including the rental of the the concrete mixer. Now, before you get ramped up and ready to pour, I will preface all of this with the drawbacks to doing your own concrete countertops.
1. This is not a project that can be completed in a weekend. No matter how small the countertop is, there's at least a 10-day curing process during which you will need to do your grinding and polishing.
2. Concrete needs to be properly sealed at the beginning and waxed about every 30 days to avoid staining.
3. The final outcome might not be exactly what you expected, especially if you're doing it for the first time. The good news is that there are ways to remedy many outcomes that you don’t like.
I also highly recommend that you buy the book Concrete Countertops by Fu-Tung Cheng before attempting ANY concrete countertop project. Fu-Tung Cheng is the master and if you're looking to be the Karate Kid of concrete countertops, buy this book. Ralph Macchio wouldn't even think of doing concrete countertops without Fu-Tung Cheng’s help.
As you'll see in this Instructable, I've got the assistance of Mr. P; an evil genius (albeit "special") who lends his raw power and expertise to the project. There are many steps that can be accomplished solo, but concrete is heavy and you should expect to need anywhere from 2 to 4 people to help move around your countertops on more than one occasion. You'll need at least 3 people involved in your pour. And it's best to cure the countertops inside a garage; however, grinding and polishing them is very wet and messy so you'll want to do that outside. Then you'll need to install them in place so prepare to have people available to help at different times.
Note from Mr. P: "If a substance does not have a MSDS, testing should be carried out before prolonged exposure. Not all methods of testing are OSHA approved. With all due sincerity; wear a mask, gloves and safety glasses when mixing concrete or using adhesives and solvents."