Instructables

Basic Concrete Countertop

Featured
Picture of Basic Concrete Countertop
This instructable shows how to build a simple concrete countertop. There are several sites on the net with good instruction and lots of details, including one here on Instructables. This project is much more basic for those who may be interested in trying to build one but want to start with something simple (relatively speaking). The countertop was for my friend's new kitchen island and was built by just the two of us with no prior experience. There are no bells and whistles, just a plain rectangular top 74 inches x 37 inches, 2 inches thick.

This will also be a reference as to problems that could arise, mistakes that could happen (read, mistakes we made), and fixes/work-arounds in case they happen to you. You don't want to spend the time building something like this only to have it end up as a small patio in your backyard instead of the countertop you wanted. Believe it or not, the concrete is much more forgiving than you'd think.

On to the good stuff...
 
Remove these adsRemove these ads by Signing Up

Step 1: Gather Your Materials, Have a Plan

The basics for making a concrete countertop are simply building your mold, pouring and finishing the concrete. There are several acceptable materials for building the form, but we chose cheap and easily obtainable...melamine coated particle board. You'll need a piece larger than your desired finished dimensions, we chose a 4 foot x 8 foot piece 3/4 inch thick. Other items needed are:

- Additional melamine boards for the sides of the form
- Sturdy and LEVEL sawhorses to build on (our finished top weighed around 400 lbs)
- 3/8 inch rebar for inner support
- Remesh for more inner support
- Wire for attaching the rebar and remesh to the form
- Screws for building the form (we used 3 inch and 1 5/8 inch drywall screws)
- Drill (you MUST pre-drill the particle board to avoid splitting)
- Saw(s), circular hand saw and/or table saw to cut the form sides. We also used a chop saw.
- Silicone caulk in a color easily seen on your Melamine (we used black)
- Concrete tools consisting of float(s) and trowel(s)
- Long screed board
- Hacksaw/bolt cutter/wire cutters for cutting your rebar, remesh, and hanging wire
- Level
- Rubbing alcohol
- Concrete (of course). We used Quikrete 5000 without additives like fibers or water reducer.
- Pigment of choice. We used a little black so the natural color would just darken a bit.
- Concrete mixer. Ours was rented and we mixed and filled everything in 4 hours.

Before you build your countertop, you should definitely build a test form. We built two 1 x 2 foot forms with rebar and remesh to test pouring consistency, color, technique etc. This also allows you to test finishing techniques on something other than the real countertop. Please don't skip this step.

Plan the size and shape of your top and mark it out on the Melamine sheet. We didn't need to make any templates since ours was a simple rectangle and was going on an island and not against a wall. Be sure to take into account the thickness of the boards being used for the walls when drawing the guidelines.

*While our sawhorses were both sturdy and level, they were only on the ends of the mold base. After curing, we noticed a very slight bow in the countertop. In retrospect, we should have had two additional supports across the length. *
dougroy1 month ago

Great project! Very inspiring!

Did you use any release compound like WD40?

shaungandrews2 months ago

Love what you've done. I'm working on a bench top too and am hoping you can advise me...

What concrete ratio's did you use?

I don't really want my finish to be showing aggregate stone etc and more of a plain dark concrete finish...similar to what you have finished with from what I can see.

Thanks for your help!

bettina-sisr2 months ago

Hello, very nice complementary instructable to go along with the few other really good ones. But what happened to the link to the slurry Fu-Tung Cheng's slurry mix.?? It is a 404, thanks for the instructable I am doing my kitchen counter tops in a similar way.

Bohemianation2 months ago

Nice job with the instructions, photo's and insets (nice touch), I am confident I could do this after your instruction.

Mz Eve8 months ago
I built a wet bar in the den and will be making concrete countertops. I am pouring in place tho...
doughyxrl11 months ago
I was wondering if you or anyone else interested in doing this have thought about doing "exposed" concrete countertops.
expatty1 year ago
We used to use a sponge dipped in slurry to wipe over the concrete. Then when it starts to dry, wipe off the excess. Also we only used 10mm galvanised mesh and it worked for much heavier applications. The only thing is that we added a chemical to stop the reaction between the cement and metal, I can't remember what the chemical was though...
Honeylam1 year ago
Nice job!
This WILL be happening here at home this summer. THANKS!
Great, i had to try this myself and its actually dead simple,

followed the steps, poored the concrete, sanded it down to grit 400 dry, added slurry yerterday evening, this evening sanding down dry to 400 and probably wet to 800, than top it with tung oil, mine fits on a BBG table.

my round DANCOOK BBG was the actual mould shape to make the round hole,

now the top of my BBG is flush with the top of the concrete tabletop.

6stygos2 years ago
If you wet your finger in soapy water you can smooth out the seams without getting any caulk on your fingers.
lkarmaz23 years ago
Most concrete counters are angle grinded to get a really shiny surface, but you seem to have achieved a reasonably good surface without it. I am doing a desk, so angle grinding is the most expensive part (I don't have a workshop full of tools).

How does the surface of your counter compare to a polished granite one in terms of smoothness and sheen?

You could be saving me a lot of work.
maliavdo3 years ago
Hy...what kind of wax did you use?
sir_eric783 years ago
did you have any problems with cracking doing the 10in overhang?
bkr1969 (author)  sir_eric783 years ago
No, the rebar went to the edge all the way around and supported it just fine.
You mention digging the concrete out of the screw heads. If you put a piece of painters tape over each screw head, it usually stays put. Just pay attention when you are screeding it.
carmankm4 years ago
What was the brand of polyurethane you used?  Can you find it at a local hardware store or did you have to special order it?
bkr1969 (author)  carmankm4 years ago
 This was my friend's countertop.  I wasn't directly involved in the finishing, but I believe he bought the polyurethane at Home Depot.  Just make sure it's marked as "food safe" or something similar. I'll try to find out for sure the next time I see him.
gabe.lopez14 years ago
Did you do any sanding?
bkr1969 (author)  gabe.lopez14 years ago
In step 10 we went over the top with a wire brush, kind of like a very course sanding.  Once small holes were exposed by this, we slurry filled and sanded them down once dry.  It was my friend's counter so he did all the sanding.  I'm not sure how course, but I know it ended up with a fine sanding and buffing.
Pro

Get More Out of Instructables

Already have an Account?

close

PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!