Alternately titled - Learn From My Mistakes. Ha ha. Before we jump in, let's talk about concrete for a minute. And some important things we learned along the way. :)
- Concrete seems like great countertop material to me. It's solid and durable, and functionally it seems similar to granite for a fraction of the price.
- Concrete is heavy. Seriously. With 6 people, we barely got our 6' piece in the house. So get lots of help!
- Concrete is imperfect. I think that is just its nature. Our finished tops have different shades and markings but that is what adds to the industrial charm of concrete. If you are a perfectionist or want your tops to look exactly a certain way, concrete is probably not for you.
- 5/8" Melamine - This will be the forms for your countertops.
- Concrete - duh. We used a countertop mix concrete from Menards. It was quite a bit more than a regular old bag of concrete ($13 vs. $3), but we wanted to make sure we got this right the first time so we splurged for the good stuff.
- Concrete dye - if you want to change the color of your concrete. We left ours au naturale.
- Welded wire mesh - something fairly sturdy to give your countertops more structure.
- Countertop sealer - see our post about sealers here.
- Silicone caulk - for sealing your mold corners and sealing your seams.
- 1/2" plywood - this will be the base for your countertop, so you need enough to cover your cabinets.
- Support brackets - if you're planning to have a bar or overhang you'll want some extra support
- 2" Screws
- Caulk gun
- Table Saw - you could use a circular saw but you need to make sure your cuts are super straight!
- Shims - for leveling your forms
- Utility Tub - for mixing concrete
- Hoes - for mixing concrete
- A Board - for skimming your forms
- Mallet or Power Sander (for removing bubbles from the forms)
Now you need a plan. If you are replacing existing countertops, you can just measure them and pour your new tops to match. If, like us, you're starting from bare cabinets, you'll need to measure the size of your cabinets and add an overhang allowance. You should plan 1 - 1 1/2" overhang on the front edges, and 1/2 - 3/4" overhang on any exposed edges (any edges that butt up against appliances would have no overhang). I found it really helpful to draw a rough sketch of the countertops so I could mark where to add overhangs and such. Also be sure to account for any odd spaces - we had to make sure we left a notch where the countertop would run in front of the window, and our farmhouse sink needed notches in the front corners of the countertop. Another option that I read about is to create a template for your countertops. This option would be great if you have crooked walls or funny angles to work with. You would just use craft paper cut and taped to fit your space exactly. We didn't have anything very tricky, though, so we just measured. Once you have your measurements figured out, you can decide where you want to put your seams. We decided to pour ours in four pieces, putting our seams in places that seemed natural like at corners (you don't want to carry anything too long because it will be crazy heavy and more likely to snap in the middle).
Prep the Cabinets
Before you install your countertops, you need to put down a base layer of plywood. We cut out plywood to sit flush with the edges of our cabinets so it wouldn't show under the lip of the countertops. For our bar overhang, we cut the plywood 1" short for the same reason.
We secured the plywood by screwing it into the frames of the cabinets. Also in prepping, you want to check that your cabinets will be able to support the weight of concrete tops. You want them to be built out of plywood (some cabinets, especially older ones, are made of thin particle board that would NOT hold up to the weight of concrete). If you're in doubt, ask a professional. If you have an overhang, go ahead and put up any support brackets you need as well.
Build the Forms
Once your cabinets are prepped and your measurements are all figured out you build your countertop forms! These will be built of melamine because it is a non-stick surface. When you pour your tops, the bottom side (the side against the melamine) will actually end up being the top and the melamine will give it an wonderful smooth finish. This stuff is pretty expensive (about $40 for the sheet) and since we like to be cheap we did some math ahead of time to figure out the most economical way to use our melamine. We ended up buying the full sheet to use (and reuse!) as our form base. We figured out that if we kept the piece whole and reused it by pouring a couple pieces at a time, we could get by with just one piece. We also bought a narrow piece (called a utility shelf panel, I think) to cut up and make our form sides.
First, you need to get your form base level. The best thing to do here is to find the levelest spot you can to work on. Lucky us - we didn't have anywhere very level. Ha ha. :) We had to work in our garage because the forecast was rainy, so we found the most level spot we could and used shims to get things as level as we could in every direction (we leveled side to side, end to end, diagonally, and really just all over the place!).
Next we cut strips to make our form sides. We used a table saw to cut our melamine shelf board into 1 1/2" strips. A standard countertop is 1 1/2" thick which is why we chose that size, but you can do what you like. I've seen some that are 2" and they look awesome...but they were probably a nightmare to carry. :)
We used our measurements to cut our melamine piece to size. Make sure you take the thickness of your form sides into consideration when you measure. You want the inside area of your form to be the size of your countertop. It sounds obvious, but trust me, you want to double check that before you pour! If you made a template of your countertops, you can just lay that on your base and build your sides around it. Easy peasy! ***IMPORTANT*** You need to build your forms upside down from your measurements. Remeber the bottom of the form will be the top of your countertop, so you need to piece to be the right size and shape when you take it out and flip it over*** And yes, we did start with the biggest section. It's called "optimism."
Once our sides were cut to the right size and mapped out, we checked for square by measuring corner to corner. Measure from bottom left to top right, then from top left to bottom right. If you are square, these measurements should be the same. (if you're using a template, skip this part)
Next we attached the sides down to the base by drilling pilot holes through the sides (spaced every 6-8"), then screwing them down with 2" screws.
Here you can see how we notched out the space for our window. :)
Once all the sides were secured, we had to caulk all the seams around the bottom and corners.You need a 100% silicone caulk for this job... I don't know exactly why, but that's what everybody says. So that's what did! This is the one we used:
One thing caulking does is keep the concrete from seeping out under the sides and creating messy edges. But wait. There's more. Remember that the bottom will actually be the top when we are done, so making nice smooth seams here will mean nice smooth edges when we are done. We wanted a nice, slightly rounded edge so after running a small bead of caulk along the seams, we used the rounded corner of a pan scraper (like the ones from pampered chef) to make the caulk smooth and rounded (to make the corner on our bar overhang really round, we used lots of caulk to fill in the corner, then the roundest edge of the scraper ) Be sure to keep a paper towel close by to wipe the excess caulk of your scraper every few inches. We found that ANY extra caulk, even the teeniest bit, showed up pretty significantly in the final product. So be sure to wipe up any excess!
Now for the wire. We chose a mesh wire that was fairly firm, but soft enough that we could flatten it out. We cut it down to be about 2" from each side and laid it in the form.
The directions on the concrete package suggested using wires to suspend the mesh before pouring, which we tried on this form. Let me tell you - this was a terrible idea. We poured the concrete and this baby sunk like a rock and we could not get it back up. There is spot on the countertop where the mesh was *so* close we can see the pattern (but it's not actually poking through, thank goodness!). We had much better luck filling the form halfway with concrete, then laying in the wire, then filling the form the rest of the way. Lesson learned.
Mixing & Pouring
We opted for a cheaper option than renting a cement mixer and decided to mix by hand. We had to mix in batches, one bag of concrete mix at a time. Using a utility tub and a couple hoes, we mixed the concrete according the directions - we started with the water then added the concrete bit by bit. (note: my dad says you should definitely wear shoes because too much contact with wet cement can actually burn your skin. oops.)
Anyway, we started by mixing the amount of water the box suggested and... we ended up with this:
That can't be right. So we slowly added more water to get it a better consistency. This is where we started to learn things. While we do think more water was necessary, it is important to add it SLOWLY. We found that sometimes a single cup was all it took to get it right. We wanted it wet, but not soupy, if that makes sense. We found that the parts where we used really soupy concrete didn't turn out as smooth as the rest, and that the amount of water used affected the final color with the runnier parts being a lighter gray.
Then we poured! And learned more (like that we should add the wire later, which I mentioned a few paragraphs ago). On our first piece we started pouring at one end and worked out way down the form, but after it dried we found that any variance from batch to batch was really obvious across the countertop. With the rest of our tops we spread our first batch across then entire bottom of the form, then added our subsequent batches on top. These tops turned out much better with an even color all the way across.
We had to work pretty quickly so things wouldn't set up before we were done. We poured in batch after batch to fill the form. After each addition - this is important - we used a mallet or belt sander to vibrate the edges of the form and release any bubbles (because bubbles now = holes in your finished top). We still had a few tiny bubbles left that made some little pin holes in our finished top, but we did get out most of the bubbles and all of the big ones!
See all that extra water in the form? That's bad. That means you are using TOO MUCH water.
As we filled up the form, we used an extra board to skim across the top of the board and get it as smooth and even as possible. To do this, rest the board on the sides of the form and slide it from end to end while working the board back and forth in a sawing motion. This will smooth out the cement and remove any excess from the form. If you have any low spots that sit below your skimming board, fill them in and go over it again until it is as smooth and even as you can get it. Now we wait.
Removing the Forms
According to the concrete mix package, we let the forms dry and cure for 18 - 24 hours (although they are not fully cured at that point). For the first form we waited the full 24 hours, for the other we waited just 18 and didn't really notice any difference between the two. Once the the tops had dried long enough, we loosened the screws in the sides of the form and pulled them away. Leaving the screws part way in the side boards gave us something to pull on. Make sure you do not pry against the cement because at this point it is still soft enough to be scratched or even gouged by tools!
We removed all the sides, then got ready to pick up the countertop and move it into the house. I don't have any pictures of this part because this thing was darn heavy and all hands were on deck! I started by laying several old towels along the right side (in the pic below) of the countertop form. Then while a few people spotted the countertop, the rest of us grabbed the left edge of the form and tipped it up. The edge countertop slid onto the towels and we kept tipping until the top was standing up on its edge. The spotters held the countertop there while we moved the form out of the way. Then we all lifted the top, making sure a strong person was in the middle to reduce the strain in the middle of the countertop and make it less likely to snap. We high-tailed it into the house... as fast as we could with a few hundred pounds of countertop. :)
Installing & Sanding
Some tips I read suggested using a caulk or adhesive to secure the countertops to the plywood base. We did a little for some of the pieces, but seriously, these things weighed a ton. I don't think they are going ANYWHERE. But if you want to use an adhesive, please, do it BEFORE anyone picks up the countertop. They don't want to hold that thing any longer than they have to. :)
Then we slid the countertop into place. Whew.
Now we had to repeat that process to build the rest of the pieces. We flipped our melamine base over to make a clean work surface, then attached sides for the rest of our forms.
Here they are drying...
By this time we had learned more about how much the water impacted the finish and our remaining piece turned out much more similar and even than the first. This is an example of how much the color varied on our first piece. We are totall fine with it, but just be warned that if you make concrete tops they will probably end up like this in some places.
After the remaining pieces dried for 18 hours, we removed the forms and installed them on the plywood base.
Now you want to sand it down ASAP. This will help you smooth any rough spots, but you have to do it soon because as the countertop cures it will become much harder (if not impossible!) to make any difference sanding. We also mixed up some slurry (which is just a super runny cement) to fill in a few of the holes left by bubbles and sanded that down after it dried. We waited 3 or four days before we let anything touch the countertop after that (which may have been over-cautious... but better safe than sorry!) and after that point were careful to work on a towel to protect the countertop because it wasn't sealed yet. I read that it takes up to a month for it to fully cure, but afer a few days it is cured enough to use with a little caution.
Time to seal! This will make your tops waterproof and stain proof. You can see our review of the sealant options here. We decided to go with the Sealer and Enhancer which slightly darkens concrete (to the color it would be when wet) and seals it without making it too shiny. We did a test section in the back corner to make sure we liked it first:
We could tell before we even opened the bottle that this was going to be a stinky job, so we put it off until we were ready to head out of town for the weekend. Then N did the dirty work while Baby B and I played outside by the packed car. :) N said it was pretty simple to apply. He painted it on, let is sit 1/2 an hour, wiped off the extra, let it sit another 1/2 hour and repeated. Then we left town, planning to come home to a beautifully finished, albeit slightly stinky, countertop. This is the piece that turned out the best:
And this is the kind of sheen it has:
But it didn't all work out that way. :) Some places (probably where it didn't get wiped off evenly) were streaky or splotchy.
The super light edges on this section are where the cement was way too runny. Like I said, lesson learned.
Here are some streaks:
And some splotches. Fortunately with some soap and scrubbing I was able to get rid of most of this and even things out quite a bit. What does that say about the long-term durability of the seal? I don't know. We'll just have to wait and see, I guess. After talking with a Lowe's employee, he suggested using a rag to kind of rub in the sealer instead of painting it on. Maybe that would have given us a better finish?
Almost done. After the seal dried we just needed to caulk all the seams to keep crumbs and especially liquids from creeping down into there. I used a clear silicone sealer for this.
And put a tiny bead of it down the seams between the pieces, around the sink, and against the wall. Don't do too much because we don't want any extra left on the countertop.
Then I used my finger to smooth it out and remove any extra, being careful not to get any on the countertop.
And we're done! Woohoo!
But I'm sure you have a few more questions, so here are a few more countertop details for you:
How much did it Cost? We did about 30 square feet (15 linear feet) and this is what we spent:
- $143 - Countertop Concrete Mix at $13/bag
- $20 - Wire Mesh
- $30 - Countertop Sealer
- $6 - Silicone Caulk
- $45 - Melamine (one full sheet and one 8' shelf)
- $40 - 1/2" Plywood for the base
- $6 - Brackets for the Overhang
- $15 - Extra Tools (shims, mixing tub, trowels, etc.)
That's about $11/square foot. Like I mentioned back at the beginning though, we bought the expensive countertop concrete mix, so if you're willing to risk regular old concrete you could do it for even less!
How long did it take? Well I'm glad you asked. We managed to all the prepping, form building, pouring and installing in one long weekend, then did the sealing another weekend. Here are some timing breakdowns:
- Building Forms, Mixing and Pouring - this depends on if you mix by hand, how many forms you build & fill, how many people are working, etc. We spent probably 2 -3 hours on the first piece and 4 hours on the rest of the pieces. It went kind of like this:
- 1/2 - 1 hour buidling each form
- 1/2 hour caulking (plus 1 hour waiting for the caulk to dry)
- 1 - 2 hours mixing, pouring, skimming
- Drying & Curing - this could be different based on the concrete mix you use, so read the package carefully
- 18 - 24 hours for initial drying before we removed the forms and moved the pieces
- 2-3 days additional curing after installation
- Filling Holes & Sanding - spent probably 1/2 hour on this... wasn't super thorough, but I'm okay with that. :)
- Finishing - like everything else, this will depend on the product you use but this is how it worked for us.
- 2 hour sealing (15 minutes sealing, 30 minutes waiting, 10 minutes wiping, repeat)
- 3 days out of the house for the stinky sealer to air out
- 20 minutes caulking
That was long and confusing, can you be more concise? Uh... well... Can you at least summarize? Yes. Yes I can.
- Measure or make a template
- Put a plywood base on the cabinets
- Build the forms (upside down! and level them!)
- Caulk the forms (wait for cauld to dry)
- Mix & pour the concrete
- pour a layer across the bottom
- use mallet or sander to remove bubbles
- repeat if necessary to fill form half way
- lay in wire mesh
- continue pouring layers & removing bubbles to fill the form
- Skim the concrete to make it even
- Wait 18 -24 hours for the concrete to dry
- Remove the forms
- Put adhesive on the plywood base if you want to
- Carefully and with much help stand the countertop up on its side, then carry it in and install it
- Wait 2-3 days for it to cure.
- Seal it
- Caulk the seams
And there you have it. Countertop DIY. Do it.
Also, grab some cheap herb plants, slap them in some pots, and see how much fresher and cheerier it makes those spiffy new countertops look.
It's magical in my kitchen right now. And it's not even done yet.