Introduction: How to Make a Concrete Countertop

Picture of How to Make a Concrete Countertop

I was amazed at how easy it is to create a concrete counter top. I've never done this before and I have little experience using concrete, but the result was amazing! Let me show you how to make your own.

Step 1: Make the Form

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It all starts with cutting a mould out of melamine to the size of the slab you want. The 2 main things to consider here are thickness and over hang. In my case I went with 45 millimetres thick and an over hang on the front of 30 millimetres. There were numbers that T decided on from my own research so as someone with little to no experience with concrete I felt safest using someone else’s experience. I’m sure you could go thinner if you wanted but the mix would need something like fibergalss added.

I then measured the inside length of the mould, which would be the total length of the counter top and lined up the strips I cut earlier.

I clamped these down and screwed them to the base making sure to pre drill each hole because you don’t want the melamine to expand from the screw. Also make sure to counter sink the holes, this’ll make sense later.

Covering the screw holes with tape makes sure that if any concrete ends up in there, and it will, you don’t have problems getting the screws out.

Step 2: Add Silicone Caulk to All the Corners

Picture of Add Silicone Caulk to All the Corners

Once all the sides have been screwed into place it's time for caulking. I’m terrible with silicone but the method I find works is to use soapy water and a lot of rags. This will be the round over on the top so find an object that reflects that edge. In my case I used a rounded pen lid. You also want to make sure that where the silicone meets the melamine there is a feathered edge. You cannot believe how precise the concrete shows absolutely every lump and bump.

After the silicone dries (24 hours is normally enough) wipe the inside surface of the form with olive oil. This will help release the concrete later.

Step 3: Mix and Pour Concrete

Picture of Mix and Pour Concrete

Then it was finally time to mix the concrete. I used a high strength mix from my local hardware store. All the videos I've watched either used Quickrete, which I don’t think we have in Australia, or it’s not mentioned. I get the feeling that any concrete, besides quick set, would work fine.

Make sure to mix the concrete as dry as possible. Using excess water reduces it’s strength.

You really want to force the first layer on concrete into the corners of the form. Because you’ve mixed it dry it won’t run as much you think.

After the first layer I vibrated using a rubber mallet.

Step 4: Add Rebar and Vibrate

Picture of Add Rebar and Vibrate

Now I added the rebar. I wish I had used a sheet of mesh instead of strips of tracks. I also researched how concrete uses rebar as strength and this helped to explain where it should be placed in the mix. Have a watch of this video, it helped me out a lot.

Then I vibrated for about an hour. You can use all kinds of methods for this but I found using the rubber mallet worked ok. Just make sure you tap the entire form. As you hit the form you’ll see bubbles rise to the surface and then pop. As it pops the hole fills with concrete, this is what you're looking for. Once this stops happening you’re done vibrating.

Step 5: Cover the Form and Keep Moist

Picture of Cover the Form and Keep Moist

I then covered the concrete in plastic to keep the moisture in and the humidity high.

Make sure to keep the concrete moist for about 4 days. You don’t need to cure it for any longer than that. Do a bit of reading up on curing if you’re unsure, it’s really interesting stuff.

Step 6: Remove the Form and Flip the Countertop

Picture of Remove the Form and Flip the Countertop

After 4 days I removed the mould. It should come away easily because of the olive oil.

I found once I had broken the water seal underneath the concrete (the side is down at this stage) using a metal spatula I was able to move the top. At 120 kilograms it wasn’t light but the water was creating a slight suction.

Then a friend came around and after lots of discussion and planning we flipped it over. Don’t he a hero, get someone to help out.

Step 7: Seal the Concrete

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I let the concrete dry for the next 4 days. Before sealing you need it to be properly dry and to test this you place a piece of rubber on top. If there is a wet spot underneath after 2 hours, it needs to dry for longer.

I used 6 coats of water based sealer starting the first coat at 25% strength then moving up to 100% on the last 2 coats. Thinning the first few layers helps the sealer to sink deeper into the concrete, improving it's ability to repel spills.

Step 8: Set the Countertop in Place

Picture of Set the Countertop in Place

Then the counter top was finished and needed to be installed. Any questions? Feel free to get in touch. Make sure to plan the whole process out from start to finish and have an understanding of each step.

But most of all, give it a go!

If I can, YOU CAN!


GoodC1 (author)2017-10-24

Awesome! Really neat countertop. You used silicone which can be tricky to work with - sticky. Would acrylic which is so much easier to work with do the same? That is smoothed easily with a finger. Or would it stick to the concrete?

Chrome98 (author)2017-03-05

you lost me in the first sentence... what is Melamine? is that a brand of some common material?

Chrome98 (author)Chrome982017-03-05

ah ha! here's what I get when I search for it at Lowes (our only local building supply store)

Bdrodge (author)2016-05-10

For getting a smooth round over on the silicone I use a tool designed for the purpose. Do a search for "caulking smoothing tool" and look at the pictures. It is tool with a special plastic that will not stick to silicone or caulking and a radius on the end. They give a nice even curve for those of us who are "challenged" at such things.

Robin Lewis (author)Bdrodge2016-05-10

Ah that'd be amazing, the stickiness is the worst part of the process. Thanks for the tip!

MichaelA473 (author)Robin Lewis2016-12-27

Use oil based modeling clay instead of silicone. Make a custom tool out of sheet metal or plastic for shaping it: basically a rectangle with one face against the mold edge nad one face on the mold bottom, with the radius cut between them. Roughly press the clay into place, and drag the tool along, firmly against the mold, as the excess clay is removed.

ty520 (author)Bdrodge2016-05-10

you can find another great tool in many hardware stores for this purpose - it is a little handheld silicone square, about the size of a credit card - each corner has a different edge profile.

They typically look similar to this:

easy application, and easy cleanup

TeresaM7 (author)2016-05-20

This is so tempting. I wonder, is it possible to dye concrete? not something weird like red or orange, but a marbled black? That would soooooo be my house! Great job, Robin! I'll keep your 'ible in case I ever get the other, more pressing things finished!

FlorinJ (author)TeresaM72016-12-27

Google acid staining of concrete. There are many commercial stains out there, but there are some people that developed DIY methods.

Only, make sure you pour several smaller pieces to experiment with, before applying it to the large slab.

TeresaM7 (author)FlorinJ2016-12-27

Good advise. Thank you, FlorinJ :)

bbkong (author)TeresaM72016-06-04

Hi Teresa!

In my meager experience molding concrete I've learned that concrete die comes in two flavors, very fine powder or syrupy liquid. Both require more than usual mixing to get the color consistent. To get a marbled finish I had to mix 2 batches (one colored) and pour them right after each other and gently stir it just a little bit with a nail. I haven't had much luck with it but the stuff I mold is pretty small, 1" or so.

I haven't tried this on something the size of a paver yet but that would be my next step so I could get some experience with it before I committed to a counter top.

For my .02 I think I would mix the batch a little on the wet side too. The bubbles come out a lot easier. I also use a palm sander to vibrate the table since it only takes about a minute.

SherylinRM (author)2016-05-20

You said you used a 25% mix of sealant.

What sealant did you use and what did you cut t with?

Thank you.

You made me see I can do this now :)

Thanks :)

FlorinJ (author)SherylinRM2016-12-27

I think you can also rub in hot beeswax. I've read other people had a good experience with tung oil.

Robin Lewis (author)SherylinRM2016-05-20

Hey Sherylin, thanks for the comment. The sealer is water based (it's used for pavers, but I think you can get a food-safe product specifically for countertops) so it was cut using water. If you used a solvent based sealer than you'd cut it with some form of spirit (thinners, turpentine, etc)

SherylinRM (author)Robin Lewis2016-05-21

Aha ok thank you. Wasn't 100% sure what you used so just wanted to be sure.

Thanks for a rapid reply :)

guerroloco made it! (author)2016-12-27

I made 2 concrete countertops a few years ago. We love them, but be warned -- they WILL pick up stains and etching from lots of different things: lemon juice, wine, etc. We added bike sprockets for interest, also made a built-in dish drainer. We used fiberglass

SergeyT9 (author)2016-10-04

Great project! Thank u for sharing!

jfalbanese (author)2016-07-08

awesome project. you might want to use self leveling concrete mix for this project. and also chicken wire , or another form of mesh wire to reinforce the concrete to help prevent cracking.

KarolinaK11 (author)2016-06-18

I love it. I am making one for my kitchen next month. Thank you.

Robin Lewis (author)KarolinaK112016-06-18

No problem, hope it all goes smoothly

Meglymoo87 (author)2016-05-19

The look of concrete is beautiful...thanks for sharing this!

Robin Lewis (author)Meglymoo872016-05-19

No problem, thanks for the comment

Morning. I have a question please. I want to make this for my outdoor barbecue and I would like the top to have seashells in it is it possible to put a layer of the stuff that's used for bar tops? I think it's envirotex or something like that. The stuff that's clear and durable.

I've seen all kinds of things added to the top, I'm sure sea shells would work great! I've never done it myself but I'd give it a try if I was you

JumpingThrghHoops (author)2016-05-12

If making a a countertop for a kitchen in a house is there a minimum depth one has to make the countertop so it is strong and will not break? My granite counter at my previous house was 2' and I know that 1.25' is sold now but I am not sure about least with cracking.

From what I've read you don't want to go less than 1.5'. I reckon professional manufacturers would be ok to go thinner but they've had time to perfect their mix.

bletwoodward (author)2016-05-12


bletwoodward (author)2016-05-12

concrete formply will leave a finish far superior to melamine or any other material, have seen formwork carpenters and steelworkers create things you wouldn't've thought possible with this stuff

Gadget93 (author)2016-05-05

Wow! This is amazing. I don't know anything about melamine. What is it and why do you use it instead of wood or something else.
I'd love to make this for my kitchen once I figure out how I'd move it to said kitchen.

Robin Lewis (author)Gadget932016-05-08

Thanks very much. I actually have no idea what melamine is made of, all I know is it's really smooth and nothing sticks to it! The other way of doing this is to cast the concrete in place, so you don't need to move it, but then you need to know how to trowel to a smooth finish. that's an art that I don't think most of us are good at.

lmnohos (author)Robin Lewis2016-05-12

i wonder if you could add stuff to the surface, maybe fabric to make patterns or class tiles randomly? if you are using some kind of sealant, that should help give it a "smooth" surface...

Senior Chief (author)Gadget932016-05-08

Melamine is the same thing as Formica. A very hard plastic that can be printed with almost any pattern but an smooth version will work to give your concrete a glass smooth finish. You can use the material to form the sides of a mold too. It is attached to Patrice board with contact cement and can be then cut to shape with a carbide toothed saw blade, usually a circular blade. For accuracy you would want to sue a table saw.

Senior Chief (author)Gadget932016-05-05

Do it in your kitchen with some drop cloths of course. Turn it over after it cures onto the cabinets!

That's a good idea

terrefirma (author)Gadget932016-05-08

I think it's because it's smooth so releases and leaves a nice finish. I have used glass to cast onto and a frame out of wood- even a drawer. and put a cutout in the middle to run a pipe through and you could set a vessel sink on top. Remember you are doing it upside down, so reverse things. And if you want to put something to show on the surface, stick it to the glass so it doesn't float up.

ty520 (author)2016-05-10

great tutorial.

I'd like to provide a little extra advice.

I helped put in a concrete counter using this exact method - we found that regardless of how many sealant coats we put on, it is still relatively porous, and needs to be resealed every 4-6 months.

I've discovered that hydrating the concrete with an epoxy resin additive makes the concrete harder and more hydrophobic.

I would also recommend adding fiberglass fibers - they act like rebar re-reinforcement at a miniature scale to help prevent hairline cracking, which can easily occur in conc counters (the epoxy will help with that, too)

Robin Lewis (author)ty5202016-05-10

Thanks for the comment, I'd never heard of using an epoxy resin. Sounds like a good idea

Abner T (author)2016-05-08

Stick to the wire mesh sheets found at local hardware stores, which is designed for thin-slab reinforcing.

Keep moisture in the concrete by laying a wet(not dripping) bedsheet or towels over the concrete, and then laying a piece of painters (1 mil) plastic over it for a few days...

SarahO33 (author)2016-05-07

I really appreciated this video....this has given me tons of ideas for a remodel...thanks for making this!

LawrenceA17 (author)2016-05-05

Unless you need a lot of structural strength,plaster lath can be used as reinforcement and especially if you're building an inside counter top. It is easy to embed into the middle of the pour,just place it and cover it up. For vibrating the concrete,use a 1/4 sheet sander on the bottom of the form,it'll explode the air trapped inside quickly. For coloring,you can use latex paint,which makes it smoother,just don't use too much. You can also use sand,gravel and Portland cement to make your concrete,giving more control over the strength.

Gadget93 (author)LawrenceA172016-05-05

I like your idea but I don't know what a "lath" is. I assume it's short for some other word. How is it used? Thanks.

LawrenceA17 (author)Gadget932016-05-07

Lath is a mesh of steel like expanded metal used in plaster wall and ceiling construction. Most "big box" stores[Lowe's,Home Depot] should have it. It's also used in tile wall and floor systems in old school systems. If I were making a 1-1/2" top from concrete,I'd put 3/4" down,embed the mesh,then pour the rest while the first part is wet. Lath comes in sheets 2x8',so easier to use.

LawrenceA17 (author)Gadget932016-05-06

Lath is what is used in plaster construction. It a mesh of expanded light gauge metal. Most "big box" building supply stores will have it. It would be more useful in a 1-1/2" depth,where rebar may be problematic. There is also a 1/2"x1/2" u shaped channel which could be placed on the bottom of the form to keep the mesh off the bottom of the concrete. If you have trouble finding lath,then use 3/8" rebar.

Senior Chief (author)Gadget932016-05-05

In this case, lath is a special wire mesh that is normally nailed to a wall or surface to allow a plaster mud finish to stick to the vertical surface. In old time construction lath was thin strips of wood with spacing nailed to the studs to hold the plaster. Wood is not called for here, the metal version is what you embed in the concrete to give it strength. You probably could use wat is called hardware cloth which is also a wire mesh in different opening sizes, normally used for a more open screening like a pet cage. Even chicken wire will work.

Gadget93 (author)Senior Chief 2016-05-05

Very educational. Thankyou.

Robin Lewis (author)LawrenceA172016-05-06

I've never heard of using paint, but I guess if it's water based than it should work a treat. Thanks for the comment

Aussie58 (author)2016-05-06

I just like it!

Were you happy with the radius of the silicon bead or would you go bigger next time? Did you use a release agent on the melamine surface such as a wax or just raw melamine?

Robin Lewis (author)Aussie582016-05-06

I think if I had children I would've rounded the edges a bit more because they are a bit 'sharp' now, but I prefer this look because it looks more modern.

All I used was some olive oil on the melamine but reading through a lot of the comments people are saying that you don't even need that. Stuff just won't stick to melamine!

Aussie58 (author)Robin Lewis2016-05-07

Many thanks for your reply.
Agree with you on all counts although I still might be tempted to use a release agent such as a wax or even PVA. I guess my experience with polyester fiberglassing, I am mindful of what happens when something does decide to stick to melaning. That said, it has only ever been on textured melamine that I have had 'stick-ups' whereas the gloss finish never seems to pose problems. I'm interested to form a shallow bsin into a benchtop - might have to think on that one for a while. Cheers from al fellow Downunder.

MartinL56 (author)2016-05-05

If I wanted to leave an opening for a sink, how would I adjust the form?
Would I just put in a second form, in the middle of the main one; before the concrete is added?

About This Instructable




Bio: I'm a woodworker/maker on YouTube
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