Anybody ever try concrete countertops? I'm about to...

[Badfish740]

The ongoing saga of my basement renovation continues....I'm getting close to finishing the alcove for the TV which is basically a built in entertainment center flanked by built in bookshelves on either side. It's actually the repurposed framework of a closet the previous owner of my house had built. Here is what the partially finished alcove looks like:

You can see where the TV will hang (the panel on the wall has a receptacle plus a pass through for coaxial, HDMI, ethernet, etc...) and the built in underneath which will house the satellite box and other assorted multimedia gadgetry. The question for me was what kind of surface to put on the topside to finish it. I wanted a kind of "hearth," (how appropriate ) so my first thought was stone, but then I thought about finding the piece, getting it cut, the cost, etc... So I started reading up on concrete countertops. It's something I've thought about doing for a while. One of these days we'd love to redo our kitchen ourselves and concrete counters would be a nice alternative to shelling out big $$$ for granite or some other stone. However, they are not the average DIY project, so I figured this would be good practice. Here is the top I've designed for the basement:

Last night I bought a 4x8 sheet of melamine faced 3/4" particle board which will be used to make the form along with some other supplies (silicone caulk to seal the form, metal lath and 3/8" rebar for reinforcement). Tonight I'll probably cut out the forms and maybe assemble them-hopefully pouring concrete this weekend! I found out that Quikrete makes a concrete specifically blended for countertops with strengtheners and anti-cracking additives already mixed in so I'm going to order three bags today as it's not an item stocked at my local big-box. I'm curious to hear if anyone else here has tackled concrete counters before?

 

[lukem]

I haven't personally, but a friend of mine has. He bought the Styrofoam forms with the backsplashes, trivets, dish-drainer, etc.

They turned out pretty good...but he works in construction and has a LOT of experience with both concrete finishing and countertop installation.

Just make sure you get a good resin/epoxy to coat it. That makes all the difference in looks and durability.

 

[ironpony]

I have done several. I do not like the idea of particle board for a form, the possibility of swelling is to great. generally using duroc or hardi backer rebar on a 1 foot grid or less for you application, run one parallel to the front edge about 2 inches back tied to ones running front to back. I would also thicken to 2.5 inches. keep wet towels on top of it to slow curing of the surface that will help with cracking.You can finish with a steel trowel to get a smooth finish and if the finish is not great you could always polish it with diamond pads, exposing some aggregate. the diamond pads are reasonably priced. seal it natural or stain it when done.

 

[ironpony]

radius the front corners by cutting PVC pipe into quarters and feathering them into the form. the inside corners you have are going to want to crack, it will be hard to prevent that.

 

[Badfish740]

I'm going to stick with the melamine board because it's easy to work with-it's widely used and most people I've seen simply tape the exposed edges with packing tape and silicone the corners of the form. I had a thought though-since the melamine will give a completely flat and smooth surface which is not necessarily what I want (a more stone-line appearance would be nice) I thought it might be interesting to spread a thin layer of sand in the bottom of the form, making it "wavy" and then laying 3mm poly over it and tucking it tightly around the corners, etc... Do you think that would give the appearance of something like a piece of cut stone?

 

[WhitePine]

We priced concrete counter tops when we were building our home in 2009. Granite was cheaper! And not just cheap granite, either.

We went with granite.

 

[Badfish740]

We priced concrete counter tops when we were building our home in 2009. Granite was cheaper! And not just cheap granite, either.

I'm assuming you're talking about having someone else do the work? Given how labor intensive it is I'm not surprised. I've seen entire kitchens done by DIY'ers for less than $600. I could have finished my basement for about $8,000 but I did it myself and probably spent about $3000 (just materials along with picking up free stuff along the way)-on the other hand I started two years ago and I'm still not done

 

[WhitePine]

I'm assuming you're talking about having someone else do the work? Given how labor intensive it is I'm not surprised. I've seen entire kitchens done by DIY'ers for less than $600. I could have finished my basement for about $8,000 but I did it myself and probably spent about $3000 (just materials along with picking up free stuff along the way)-on the other hand I started two years ago and I'm still not done

Yes, done by a professional. We found that granite was cheaper than concrete and most other materials, too. About the only thing cheaper was laminate. It was really surprising.

 

[Badfish740]

Made a template from 3/4" plywood and tested the fit:

I'll eventually cut the piece down and use it as an underlayment for extra support.

 

[semipro]

I've seen some good articles in Fine Homebuilding on this. They recently mentioned the availability of bagged concrete.
Don't forget the built-in dish drainer. I think that's a great idea.
Not sure if you've seen this article. Its dated but.... http://www.finehomebuilding.com/PDF/Free/021090086.pdf

Edit: found this too: http://www.finehomebuilding.com/item/22305/heres-how-to-do-a-pour-in-place-concrete-countertop

I'm curious. What do you plan to seal it with? I'd like to do concrete but the requirement for sealing is my only concern.

 

[semipro]

I believe the bagged concrete contains reinforcement fibers also. If so, you may want to skip the metal lath and just add some rebar along the longer sections. Unless you can very carefully control the position of the metal lath it can move and end up too close to the finished surface causing problems.

 

[Badfish740]

Don't forget the built-in dish drainer. I think that's a great idea.

I agree, but it might look a little weird under the flat screen TV

I'm curious. What do you plan to seal it with? I'd like to do concrete but the requirement for sealing is my only concern.

There are a lot of options out there-plenty at the local big box. The sealer is the first step. After sealing you then need to wax it about every 30 days for kitchen use (since mine will be in a dry location I will likely only wax it once)-you can use 100% caranuba wax which is available at any auto supply store-it's safe for use around food.

I believe the bagged concrete contains reinforcement fibers also. If so, you may want to skip the metal lath and just add some rebar along the longer sections. Unless you can very carefully control the position of the metal lath it can move and end up too close to the finished surface causing problems.

My biggest fear is cracking, so I'll be using rebar, lath, and fiber reinforced concrete. I've actually decided to make the slab 3" thick (again, because I'm worried about cracking) so I'll pour 1.5" of concrete, lay the lath on top (cut to the pattern of the slab, but one 1" off of the edges), incorporate the rebar, and carefully place the concrete on top. I've seen countertops done without rebar, but never without lath or reinforcing wire, plus I haven't seen too many issues with using it. Starting on the form tonight!

 

[semipro]

Sounds like you've thought this through pretty well.

I guess one thing to keep in mind when you're putting all that steel in there...concrete is not water proof. Moisture eventually makes its way in and corrodes metal reinforcement causing spalling. Its happening to much of our transportation infrastructure.

Of course, (now) i realize you're not expecting much water around your TV so it probably makes no difference given your application.

Can't wait to see how it turns out.

 

[Badfish740]

I guess one thing to keep in mind when you're putting all that steel in there...concrete is not water proof. Moisture eventually makes its way in and corrodes metal reinforcement causing spalling. Its happening to much of our transportation infrastructure.

I think that's why they recommend sealant (I've seen as many as three coats) and the frequent waxing. I've seen a lot of pictures of concrete countertops in kitchens-if this goes well I'll definitely do them in the kitchen as well.

 

[Shawn Hays]

You are definitely on the right track. You will find a lot of useful information and videos at www.buddyrhodes.com and askbuddyrhodes.com. You can reinforce with fiber. No need for the metal.

 

[mikefrommaine]

I've made counters for 5 kitchens. Always done 1.5" thick with rebar tied together and wired to edge of the forms so it stays in the middle so I don't have to worry that it sinks to the bottom and shows through what eventually becomes the top. Never had any issues or concerns with cracking. The latest sealers and wax from cheng concrete hold up well, much better than the food safe sealers from 10 years ago. And they don't have a thick ''epoxy" look to them.

 

[NE WOOD BURNER]

Check out the Soapstone counters. I think they look cool. Craigslist has lots of used pieces of granite and soapstone that can be cut very nice for cheap! Headstone dealers sometimes have odd pieces lying around also that can be negotiated.
I understand that the concrete can be died to your color and or have patterns etched/painted on before sealing? similiar to walkways
Post some pics when you getta done!

 

[Badfish740]

I've made counters for 5 kitchens. Always done 1.5" thick with rebar tied together and wired to edge of the forms so it stays in the middle so I don't have to worry that it sinks to the bottom and shows through what eventually becomes the top. Never had any issues or concerns with cracking. The latest sealers and wax from cheng concrete hold up well, much better than the food safe sealers from 10 years ago. And they don't have a thick ''epoxy" look to them.

What did you use in your mix? I've seen a couple of different "formulas"-some use regular high strength (5000 psi) concrete with fiber added and some use that plus anti-crack additives of various kinds. Still others use a type Quikrete makes specifically for countertops but it's pricey at $14 a bag plus no one stocks it so it takes a long time to get.

 

[mikefrommaine]

I've been using cheng concrete mixes. Results in a nice dense slab. But make sure you have two people to do the pour, it tends to set quickly. And make sure you have a way to vibrate the forms. I bought a cheap harbor freight vibrator. Makes for much fewer voids. I used standard $3 a bag quikrete. On my first counter I used fiber but the strands can show through. Which you can burn off with a torch during finishing. Don't think fiber is necessary though.

(broken link removed to http://store.concreteexchange.com/CHENG-Concrete-Online-Store_5/CHENG-Concrete-Countertop-Pro-Formula-Mix-and-Supplies_2/CHENG-Concrete-Countertop-Pro-Formula-Mix)

 

[Badfish740]

Finally poured today!

Here's the empty melamine form-I sealed all of the exposed particle board edges with clear packing tape so as to guard against water swelling it, and then caulked all of the corners with silicone which should produce a nice rounded edge:

$40 Mixer rental from Home Depot and 5 bags ($70) of Quikrete Countertop Mix:

Mold release agent:

Finished product:

I'm going to leave it in the mold at least seven days if not longer-it should reach 3,500 psi by then. Quikrete's literature says that the mixture eliminates the need for mechanical vibration but I gave the form a good tapping with a hammer all around and then went over the entire thing with a random orbit sander-there were a fair amount of bubbles. Can't wait to see what it looks like!

 

[UMainah]

I'm going to leave it in the mold at least seven days if not longer-it should reach 3,500 psi by then. Quikrete's literature says that the mixture eliminates the need for mechanical vibration but I gave the form a good tapping with a hammer all around and then went over the entire thing with a random orbit sander-there were a fair amount of bubbles. Can't wait to see what it looks like!

I would cover it with plastic sheeting and after it sets up I'd make sure it was staying damp for those 7+ days you leave it there.

 

[Badfish740]

I would cover it with plastic sheeting and after it sets up I'd make sure it was staying damp for those 7+ days you leave it there.

I didn't include that but I do have it covered right now. Especially importance since the wood furnace resides in the basement not too far away from where the countertop is curing. I was planning on also checking it every day and giving it a spritz with a spray bottle. When I worked construction for my cousin we poured a huge garage pad during a really hot summer and he set up a series of lawn sprinklers around the pad and let them run during the day for an hour or two at a clip for a week. Not one crack!

 

[stee6043]

I can't wait to see how this turns out. I've been watching this thread since the beginning. I'm considering doing a concrete bartop for my basement. Pennies on the dollar compared to real rock. Looking forward to seeing how yours turns out!

 

[legrandice]

I will be following your progress here. I too have been kicking the idea around for when we redo our kitchen. That project keeps getting kicked down the list lower and lower...but it will get done one of these years!

 

[Badfish740]

*bump*

Does anyone have sealer recommendations? I was going to use something generic like this:

http://www.quikrete.com/productlines/concretesealer.asp

Then I'll follow up with wax once it's dry. Planning on popping the form this Saturday.