I really want to try to make one. We have a simple 4' long island in our kitchen, so it would be a good place to try it out. I figure if it looks like crap or doesn't work out, I'll just put the crappy laminate top back on for now, till I can afford something else.
I helped a friend do his. Make sure you buy the correct concrete. It was not very difficult and the results are nice at first. Having said that the costs start adding up if you decide to add colors etc. His also has a few chips on the edges where things have hit. He currently is looking to replace with granite. The granite for a common color is not that much more than he has in the concrete.
Did mine about 10 years ago. Wanted color to match the tumbled stone backsplash we were using. I did a number of mock-ups using integral color concrete and just couldn't get the results I wanted. I ended up using a tan color hardener as my base color, then the wife mottled it with acrylic paints. Sealed it with a USDA approved Laquer based clear sealer (VERY expensive).
It's lasted just fine. I do need to recoat the sealer, as there are some high use areas that have chipped over the years.
All in all, we love it.
I've seen some that look great. Gives you the option of some shapes and forms that you can't get in other materials. They aren't super hard to make. They are really grout not concrete. Add a lot of air and fiber mesh. If I were doing them I'd also add fumed silica. They are too porous for kitchen use without a sealer.
You could possibly coat them with epoxy afterwards to seal them well.
I wouldn't be very likely to put them in my kitchen because they aren't any cheaper than some low cost solid surfaces. If I were single, I'd have stainless counters and racks with no cabinets.
I just finished installing my precast countertops. Getting to the finish line had a lot to due with the generous help provided on this forum. I thought I would provid a little insight to other DIY'ers considering concrete countertops.
A little background...I am a Project Manager for a Heavy Civil contractor so I have some education and real life experience with concrete. However, I don't build forms, pour, finish etc. I have great respect for those who do.
I am in the middle of a budget kitchen remodel and figured if I can manage the General Construction of bridges and retaining walls, I should be able to tackle a couple countertops. No problem. It's just concrete right?
Here are some lessons learned/advice:
1. Don't use quikrete countertop mix. I tried to simplify the process by using it. The process got a lot more complicated by quikrete and my final product is weaker and less consistant. In order to get the same slump from bag to bag, I would sometimes need to increase the water significantly and add super p and water reducer. It is not that difficult to buy the ingredients and mix your own. Search this forum and you will find a couple simple mixes. I made a lot of mistakes when building my countertops...quikrete was hands down the biggest.
2. If you have a very specific countertop in mind (or you are a perfectionist), you should plan on making a few test pieces, or hiring a pro. Form, pour, strip, cure, polish...repeat...repeat. If you are okay with your countertops turning out a little different than your (or your wife's) vision, you might not need to make test pieces.
3. They will take more time than you think. I didn't keep close track of my time, but I probably have about 70 hours into them. If I did it again, I could do it in 40-50 and they would turn out better.
4. Mine cost about $900 but I borrowed a mixer and wet polisher.
5. You might enjoy the process and final product more if you can embrace the unique characteristics of your countertop. I had trouble with too many pinholes and color matching problems due to quikrete. I used a darker slurry to fill the pinholes and like the effect. Also, my kitchen island has some color variation and swirls that add visual interest.
6. I used Buddy Rhodes Penetrating Sealer and Satin Sealer. I am glad I did. If you watch his Youtube videos, you can see how easy it is to apply. I considered using a more effective sealer, but I am glad I kept it simple.
7. I tried to pour a couple test pieces without a stinger and had way too many air voids. Rent a vibrator.
To add to Anthony's posts,I also work in civil construction, though in field management, and poured our own countertops 4 years ago.
I didn't get too technical with mine, I'm a fan of the simple and classic, so we dyed them black, added a few ammonites, a bread proofing area, and an integrated drain board.
I bought a Fu Tung Cheng book and due to being just overwhelmed with work, I followed his steps to a T, and am happy with the results. There's definitely a difference in pouring material that simply needs to look somewhat o.k., and have a solid 28 day break strength, and having a sealed architectural element in your house that your wife will scrutinize a couple 3+ times a day for the next many years.
I have more time in mine that Anthony, but I like I said above, I added a piece of stone for the wife to proof bread on, and I build an integrated drain board with brass rails that I bet I have over 40 hours of hand sanding in alone. With that said I'm tighter than a ducks butt with my own money, addicted to DIY, and it looks super t1ts, so no regrets there.
Fu Tung suggests using Quikcrete 5000PSI sack concrete (HD has in here in the PNW) and we've had broken plates and glasses but no chips in the counters.
If you choose his method through his site, he has a project calculator that dumbs down the needed admixtures (his are pre batched from Interstar in Quebec) This was my first time using this much water reducer, and the pour came out gooey, and was like striking off sticky gelatinous baby poo. Just a heads up.
I went 3" thick (had to reinforce the cabinets) and also suggest using a vibrator of some sort (tapping the form with a hammer isn't enough, a full sized vibratory is too much) We used a Bosch bulldog rotohammer by drilling a bit into a piece of 2x4 flat side 1/2 way, then switching the rotohammer to chip mode, and just sort of vibrated our way around. I had 0 spots to sack and patch besides the tiny pin holes that need to be re-slurried as in any architectural pour. You may laugh, but if I had to do it again I might get a cheap hard plastic vibrator and use that to work around the faucet holes and edges, areas that you're most worried about voids in.
I like them, and don't regret them, but for the next house/cabin/whatevs I'll probably do an engineered stone.
The this old house repair show had a spot on counter tops. The pro did a very nice job. But it still isn't to my liking. For less money and less work, for me using leftover stone is much nicer.
My kitchen is on it's way to being commercial looking and I think concrete is still out of place. Maybe industrial or ultra modern you could get away with it.
Constructeur, what heating element did you put under the stone to make it usable for proofing? Plain stone is too cold, that is why they use it for pastry dough. Three of the ovens in my kitchen have proof mode so I am curious.
Yeah installing a countertop is always a good idea. I agreed that plain stone is cold but sometimes you need to plan ahead to think about it. Proofing on the stone is another one of those important things that you should never miss out. I installed cayenne cognac vanity counter top and it worked out pretty good for me.
Cleaning concrete counter tops can be an issue, especially if they have had anything acidic split on them. It can also leave "wet mark" residue after cleaning - this dries after about 30 minutes, but can give a strange look to the counter top in the meantime.