Searching For The Perfect Concrete Countertop Design

I've had a lot of fun creating sample concrete countertops.as you will be able to see from the pictures I've posted below.  You might think I've done a lot of this before; however, I have not.  My prior experience with concrete was with setting fence posts by digging the hole, throwing the bag of concrete mix in the hole (not even bothering to open the bag), then pouring some water in the hole while shredding the bag with the shovel and mixing everything together.  

The process of remodeling my kitchen has been fun because I've been able to learn almost everything I needed to know via sources on the internet.  Before the World Wide Web we had to learn things from books, school, or other experts.  With the World Wide Web anyone can watch DIY videos on YouTube and other web sites.

I've also been able to buy specialized supplies over the internet.  For the earlier stages of our kitchen remodeling project I was able to buy most of what I needed at the local hardware store.  Now that we have finished phase one and are starting phase two, I've found that the work in phase two is more specialized and there are things I can't buy at any local hardware store.  For example, the I've not been able to find any local sources for the following:

  * 10mm PVA Glass Fibers (blueconcrete.com)

  * AR Glass Fibers (blueconcrete.com)

  * Diamond resin embedded polishing pads (ebay:tools4stone)

  * Diamond profiling router bits (ebay:urdiamondtools)

  * Wet polishers (ebay:tools4stone and specialtydiamond)

  * Plastisizers (blueconcrete.com and directcolors.com)

  * Pozolians (ebay:venturabreeze)

With a little searching and help from friends, I was able to find local sources for the following:

  * White Portland cement (Buehner Block in Salt Lake City)

  * Lithium-silica concrete sealer and hardener (Intermountain Concrete Specialties in Salt Lake City)

  * Color/pigments (Bhuner Block in SLC)

  * Fine aggregates from PetSmart in the aquarium section

  * 3 1/2 cubic foot cement Mixer from Harbor freight

I could only find the following items for my concrete countertops at my local HomeDepot or Lowes:

  * Acrylic Admixtures

  * Rebar

  * Wire Mesh

  * Foam board for cut-outs

  * 15-amp Makita 7" Angle Grinder

  * Rigid 7" Turbo grinding cup (the orange one, not the blue one)

  " 4'x 8' sheet of melamine for my non-stick pouring table

  * 3 saw horses for pouring table

  * Lumber to support my melamine toped pouring table

  * Some decorative aggregates

  * Gloves, goggles, face mask and other safety equipment

  * Mixing buckets

  * Misc hardware and tools (i.e. trowel and float)

I also found the following websites an invaluable wealth of information:

http://www.concretenetwork.com/

http://www.trinic.us/

Both sites offer a wealth of information

One of my first objectives was to determine the concrete recipe to use.  Here is the recipie I used for a sample batch that I've adjusted up or down 

  1 lb Portland cement

  2 lb Sand

  0 - 2 lbs aggregate (depending on desired effect)

  1.6 Oz of Super Sealz

  2 Tbs PVA Glass Fiber

  3/4 tsp Color Pigment

  8 oz of Acrylic Addmixture

  2 - 8 oz of H2O (depending on slump)

I've found this mixture is great for small batches, has a high cement ratio for high performance concrete, and uses very little water.

I measure out each ingredient on a digital electronic food scale (wallmart), starting with the dry ingredients then adding the fluids.  I've been mixing the concrete until I can make a ball of it in my hands that remains solid as I move the ball in my hand, yet falls through my fingers when I let the ball rest in my hand.  

Once the cement is mixed, I pour it into one or more molds and let it cure over the weekend.

After the concrete has cured for at least 2 days, I can de-mold it and begin to grind it to expose the aggregate just the way I want it.

Once the aggregate is exposed I polish it up with the diamond polishing pads.

Usually there are voids and pin-holes I need to fillwith a slury mix.  I've been applying slury after grinding and polishing up to 200-grit.  I've even tried adding the hardener/sealer to the slury which has helped me rapidly slury coat my samples and resume working on them in a couple hours.

When I've polished the concrete slabs I've started with a 50-grit padd then worked my way up to a 6000-grit buff pad.

So far, I've created 17 samples.  Here are the latest ones:

My favorite is the one in the upper right corner.  My wife April decorated this one.  I call it, 'A River Runs Through It', after one of the last movies Robert Redford made.

Right now, there is just too much pink/orange in the color.  It's time for me to abandon using the buff color and switch to one of the other colors that's a warmer yellow.

Fabricating Sample Kitchen Countertops

Now that our kitchen has new lighting and paint, April and I would like to see what we can do about replacing our old formica kitchen counter tops.  When we started our kitchen remodeling project I had originally envisioned resurfacing them; however, as we worked on the kitcen we noticed things with the counter tops that we wanted to change.  

For example, when we were removing the cabinets from the kitchen we noticed that the countertop next to the ovens wasn't straight.  When I measured the depth of the countertop next to the oven I found it was 1/4 of an inch narrower on one end than on the other end.  Later in the remodeling project I accidentally burned a nice little hole in the island countertop.  There is also the issue of our old and obnoxious kitchen sink.

As with any remodeling project, the more we looked at the kitchen, the more we saw that we wanted to change it.  The problem with this is that, in practice, we never stop finding things we want to change, but I digress.  Ultimately, we just compiled mental lists, prioritized the list, then work on the tasks in iterations.  Kind of like Agile software development practices.  

The next items to replace in our kitchen remodeling project are the countertops.  We have countertops around the perimiter of the kitchen an on an island.  The challenge with the countertops around the perimeter are that we have a stove, sink, and large U-shape to deal with.  At the moment we think that we want the perimiter counter top to be one giant contiguous piece.  Concrete is very heavy so if we do keep these as a single contiguous piece then I'll be pouring them in place.  As for the island.  The island is quite large; however, with the help from a few friends we can lift the countertop so we will fabricate it outside and bring it in when it's done.  

It's important to us to be able to have at least one countertop available at all times so we will start simple and pour the island countertop in the cure it, grind it, polish it, and seal it in the garage first.  Once the countertop on the island is ready for full-time use, then we will turn our attention to the perimeter countertops.

Before I even think of pouring a counter top I'm going to try pouring some samples.  I've already started pouring samples and have achieved some surprisingly great results.  

Here is the very first sample I poured

It was important to me to be able to re-use the mold so I made one out of malamine

I've secured the melamine sides of the mold to the melamine sheet on the bottom with 1-1/4" dry wall screws then sealed the corners with black 100% silicone goop.  The silicone will give a nice round edge to the concrete and make it easier to remove the slab from the mold.  Before I poured the concrete into the mold I rubbed a little olive oil all over the inside of the mold to help release the concreate from the mold.  By the way, the olive oil work perfectly so I'm not sure why anyone would ever buy a specialized form release agent.

Before I poured my first sample I did some research on concrete countertops and found several recipies for DIY-ers, made a list of ingredients I'd need to purchase, and researched where I could buy the supplies I needed.  Surprisingly, I could only buy about half of what I wanted from Home Depot or Lowes.  If I could have accepted black or grey countertops I could have purchased most of what I need from the local hardware store; however, I'm picky and hate grey.  I also don't like pure white; however, I have more control over the color of my countertops with white cement because I can add pigment and stains.

For supplies for my first sample I picked up white Portland cement, white quartz sand, Ultimate Fortifier addmixture, silica fume, buff cement color, assorted aggregates, and a colloidal silica hardener/sealer.  The aggregates I picked up to try out were white marble, greay grannite, decorative pea gravel, and brown glass to grind up.

Despite all the cool aggregates none of them mean anything unless the surface of the concrete is ground down to expose the aggregate.  The bottom slab is fresh out of the mold but the ones on top were ground down into the aggregate.

In order to grind the concrete down to expose the aggregate I need some specialized tools.  In my research I found the consensus to be that a high-speed grinder is needed; howver, in order to polish the concrete, a high-speed angle grinder would not work; rather, a variable speed, watter-fed polisher is needed.

In order to pour larger slabs I've created a table in my garage.  The table consists of three saw horses, 2x4's, a 4'x 8' x 3/4" sheet of particle board, a 4'x 8' 3/4"  sheet of MDF and a 4' x 8' x 1/4' sheet of melamine.  I've also decided to try creating my forms without using dry-wall screws; rather I've used a hot glue-gun to tack down the sides of the forms onto the 1/4" sheet of melamine.  I've also mitered the sides of my 1-1/2" melamine strips.  Like this:

The roll of galvinized wire is going to reinforce the concrete.  When I poured the concrete into the larger 2'x2' molds I trimed the wire to fit within the molds and be between 1" and 2" away from the edge.  I also just pushed the wire mesh into to concrete after puring it into the molds. 

In the photo below I've removed the slabs and flipped them over after letting them cure over the weekend.  The closest slab has also been ground to expose the aggregate, an inexpensive pea gravel I picked up from home-depot.

These two slabs (above) are 2 feet by 2 feet and 1-1/2 inch thick.  Both of these slabs will become table tops for end-tables.  

Unfortunately, I'm not happy with the results of the two new 2" x 2" slabs.  I put too much color in them.  I'm also not happy with the color of the aggregate.  I feel I can do better.  April likes the slabs but agrees that they are too dark.  We both prefer the color in this slab:

However, we like some of the color of the aggregate in this slab:

We don't like the pink rocks or the broken glass in the slab above so our quest to find the perfect concrete mix design contines.  

For our date-night on Friday we went to the large Home Depot in Sandy to look at the Silestone countertops to seek some color inspiration.  We found that we actually liked the black flecks in the engineerd quartz countertops, so with some new-found inspiration, I went to Petsmart and picked up some bags of decorative Aquarium gravel.  It turns out that Petsmart has a huge variety of colors.  I picked up 25 lb bags of black, brown, and white gravel, as well as a 5 lb bag of black large-grain sand.  April also went to michaels and picked up a bag of green recycled glass that has a mirrored surface on one side, and a bag of beautiful brown aggregate.  

Last night I cut 1-1/2" forms to make four 1-foot square forms.  This time I'm not using the glue gun; rather I've fully taped the sides of the forms and have just used the black 100% silicon caulk to secure them in place.  I'd like to re-use these square foot forms.  Plus, It'll be much easier to convert the mixtures I use into larger portions when I do the final pour.  Here is a picture of the forms:

As  you can see from the pictures, I'm also going to experiment with rounded corners (closest mold) and sink knock-outs in the 2nd and 3rd form