ask big al

Hey Stephane,

We have a method for putting sealing countertops and concrete objects that is time and labor intensive but gives great results! We cut our sealer with water and apply it with a microfiber cloth over a week or so. We have the cloth wet with sealer and hand work it into the piece, allowing the sealer to penetrate deep into the concrete. The concrete will darken when applying the sealer and lighten when the sealer cures. The first coat is very important because each application will inhibit the sealer from penetrating. The last coats, 7-10, are topical coats that cross-link with the other coats.

1. apply sealer liberally to the concrete piece working it in random, circular movements.
2. make sure that the sealer has penetrated to a sufficient depth.
3. wring out the microfiber cloth and quickly wipe down the piece in random, circular movements.
4. repeat step 3

It is important to not work the sealer too much when doing the final wipeoff. the sealer is self-leveling and should bee free of streaks. Lightly sand between coats If streaks occur.

Here is a video of the process

giving the world hand rubbed beauty,

Big Al

Hi Pierre,

The USGBC does not certify products for LEED. They certify buildings based on six different areas. Concrete counters have characteristics that apply to some of these categories. The use of concrete counters and other products may qualify your project to earn LEED points. Architects and LEED Accredited Professionals (LEED APs)can give you straightforward answers about LEED certification on your project. Different concrete counter craftsmen have varied methods of producing a "green concrete countertop" and some may be more environmentally friendly than others. Please keep in mind that countertops, be they concrete counters or other solid surface materials, are just a small part of most projects and their contribution is usually small as well. Concrete counters are like the cherry on top of your project, a piece of art in your kitchen.

Good luck on your project,
Big Al

Fibers can be used. We use fibers in our countertops and formed objects. The finished surface should be free of fibers. Big Al knows that the care that goes into pouring, trowing and curing a concrete slab has a big effect on the final product. Slabs that are poured on hot days and dry out before the concrete is cured can cause some interesting things to happen with the acid stain. The acid stain is mostly water and water is the one thing that the dry concrete craves to continue it's hydration. Once the concrete has the acid applied it resumes curing. This can cause an uneven appearance. An additional coat of acid can even things out but that can add a day to a project. Big Al suggests talking to you contractor about keeping the concrete slab wet during the initial curing phase.A good article on concrete slab curing can be found here.

http://www.concretenetwork.com/concrete/slabs/curing.htm

Always,
Big Al

Hey Char,

Big Al has used lots of cleaners on concrete countertops over the years. I have found that most of the time the stain is in the sealer and has not made it to the concrete. Big Al's philosophy is to use the most gentile method first. The most gentile abrasive cleanser that Big Al uses is baking soda. Baking soda is alkaline, works great and cheap! Any household cleanser that has the word gentile on the packaging should work. Big Al works the area dry or mixes in a little water to form a paste. Big Al has used soft scrub with bleach to remove strong stains like yellow mustard. Cameo and Bon Ami are good choices.

keeping it clean,
Big Al

Big Al loves cooking outdoors year round. A concrete countertop in your outdoor kitchen can be the centerpiece of your space with very little effort. The guys at Alpha Stone Concrete have made concrete bars and concrete countertops that have braved many New England winters and they still look great!

The most durable concrete is made with just the right amount of water in the mix. A properly made concrete countertop is free from cracks. The winter freeze-thaw cycle can make a tiny crack a big problem. Alkaline resistant glass fibers as well as polycarbonate fibers can help prevent cracks too. A ground surface is more durable, less prone to staining and is easier to repair. Proper sealing during the year will keep your outdoor kitchen looking new.

Concrete countertops, like most any outdoor equipment, should be covered with a tarp when not in use. Big Al recommends spending the few extra dollars and get a good tarp from your local hardware store. They pay for themselves by lasting longer and protecting you outdoor kitchen.

cooking year round,

Al

Hi Elaine,
Often when a concrete countertop is stained it is only the sealer that has the stain. Try a mild abrasive cleaner. Use it as dry as you can to abrade off the upper layers of the sealer and apply more sealer when the stain is gone. Florescent paper like sticky notes are really prone to bleeding and staining. However, the bright color does fade over time.

Please let me know how this works out.

thanks,
Al

Thanks for asking Big Al this question about epoxy and urethane sealers. If you ask someone that hopes to make a buck or two off you , they will sing the praises of their products and tell you how many satisfied customers they have.

Just yesterday the guys from Alpha Stone Concrete were down in Manhattan installing a concrete sink. To our surprise, there was another concrete countertop specialist at the job site repairing the countertops in the kitchen. These countertops were sealed with epoxy and urethane and had many scratches. We learned from our many experiments with these types of sealers that they often peel and tear away from the concrete over time. Surfaces with a ground finish often fare better than others.

Concrete is a naturally porous material. To make the surface repel moisture and stains, we add a coating of sealer that is usually some form of plastic. The trick is to have a product that does a good job at sealing without making the concrete look like a big chunk of plastic. Another concern is that as the concrete continues to cure over the years it may form deposits on the surface of the concrete. These can become trapped under a sealer

So, when Big Al thinks sealer, he thinks long term wear and repair. There is no silver bullet when it comes to concrete sealer for countertops. I suggest a sealer that is easy to apply and reapply as necessary. It may not seal as well as some of the other epoxy and urethane sealers but, you may find that it as better choice in the long term.

Here is a link to some information on the sealer that the guys at Alpha Stone Concrete use. http://www.concretenetwork.com/products-sealer/solution-library/pro-seal...

Good question finsher,

Mineral oil is not considered a sealer. Concrete is very absorbent and draws the mineral oil in. When concrete is saturated with the mineral oil it repels oils and other liquids. The oil can be applied with ease and is available anywhere. The finished concrete has a natural look and feel. Mineral oil is often used with a layer of wax to get a true seal on the concrete. Our first concrete counters were "sealed" with mineral oil and a layer of carnauba wax. The look was very appealing and had a nice feel. The counters were prone to water marks and staining. Modern sealers can give you a natural, durable and stain resistant seal. They are also very easy to apply. So the only advantage, as I see it, to using mineral oil is the price and availability.

doing the concrete thing,
Big Al

Hi Paul,
That is a very natural way to help seal and protect concrete. I've used that method for my own countertops in first house that I built. It feels silky to the touch and makes the concrete look real and not plastic. However even though you've somewhat satisfied the materials need to absorb by introducing oil it will still be thirsty in the near future and even though you've somewhat sealed the surface with the wax it will fail in the near future. By reapplying oil and wax i was able to keep my counters relatively unscathed even with kids. The only lasting blemish that I remember on those counters happened the time they made lemonade and left cut lemons on the counter all afternoon. It left an etch that could never be righted. Put as many coats of oil on before you wax and don't let the wax build up too much or it will spot from water.
If life gives you lemons?
Al

We've used many different methods to seal and protect our creations over the years including mineral oil, wax, epoxy and urethane. All have + and - and none are perfect. All stone surfaces should be sealed and protected not just concrete. Currently we are employing a two tiered method for protection. Roughly 7 days into the hydration phase we apply a highly modified catalyzed potassium hybrid siliconate. I use V-Seal 101. Then after about another week I begin to apply a polycarbon/polycarbonate hydrocarbon resistant film sealer. I use Pro Seal ultra shield 11A. I apply 6 to 10 coats one coat a day at 65 degrees and allow to cure in between coats and for at least 72 hours before use after the final coat. But that's just me.
We always use protection.
Al

Hey JC,
Carrying concrete samples around isn't your kind of workout? The good news is that you can choose a color by going down to your local hardware store and choosing a color from one of the paint chips provided by the paint companies. They are free and you can usually take as many as you want. You can then email or fax the color name and number to your concrete contractor. Concrete that is acid stained or has exposed aggregates are harder to match. You can ask for photos of some of the more exotic samples. The truth is that even a concrete sample will appear slightly different from a finished piece. When I pour a concrete countertop, a stanchion wall and a sample from the same batch of concrete, they all look slightly different.

Oh the wonder and mystery of concrete! Keeping a consistent color within concrete project is a challenge. There are many factors that that will affect the color of a concrete piece. This can be especially difficult when trying to match a color swatch. Big Al has had some real head scratchers in the past and the guys at Alpha Stone Concrete have put together a standard operating procedure to address this characteristic of concrete.

Try to eliminate as many variables as you can. The weather and temperature of your materials will have an effect on the look of your piece. Use pigments, cements and aggregates from the same batch or lots. Some aggregates may have dust or organic materials in them that will change the color. Take a look at two bags of portland cement that you purchased from the same vendor on the same day an you may find that the country of origin maybe different.

I am guessing from your question that you used a premixed bag of concrete. Many of these mixes uses a minimum portion of cement recommended for decorative concrete. If you poured them on the same day and used the same form material, the changes can be attributed to inconstancies in mixing or troweling. The thin layer cement paste is usually lighter than the rest of the mix that contains aggregate. Troweling methods can have a big impact on the finished appearance.

Big Al knows from experience that different thicknesses of concrete, even poured fro the same mixer, will have a variation in color. We have a display in the Alpha Stone Concrete show room that has sample from 1 1/2" - 5" thick. You can compare these to our standard samples that are 1" thick and a sample 7/8" backsplash. They are all different, within an acceptable range and beautiful.

yours,
Big Al

Hi Lisa,

Sorry that I am jut getting back to you now. We have been very busy with two very large jobs that use recycled glass as an aggregate and that means a lot of sourcing, soaking, smashing and sorting. Whew!

Too bad about about our version of ice stone not making the customer happy. I like the look of ice stone too, I understand that she wants the real thing. As far as the house with the cracked concrete countertops, removal and replacement of the countertops is all we can do. The cracks are an indication of poor manufacture. We replace our products if the ever develop cracks that are larger than the surface hairline cracks that sometimes occur naturally in concrete. Here are some likely culprits for the cracks.

• Large, structural cracking can happen when too much water or the right mix of cement and aggregate is used. A concrete countertop is very different from a sidewalk or slab that is supported throughout its entire area and needs to be super strong because it is resting only on base cabinets edges.

• The house may have settled and caused event the most well made, best installed countertops to crack. This is true for any solid surface.

• Some mistake may have taken place during the installation.

As far as the color, there is not much that can be done except for grinding and exposing the aggregate. The countertops have been sealed and used so acid staining is out of the question. I would be wary of anyone that claims to have an overlay that goes over the concrete. We get requests to do that for people all the time. We even got a developer asking us to put concrete over granite!

That's it. I hope that that answers your questions.

Eiko,

An easy way to get started is to choose a color from a color fan at your local hardware store. Concrete can be pigmented almost any color. Email the name, number and vendor of the paint.A sample for your approval can be mailed to you for your approval.There is often variation between samples and countertops, so consider that there will be concentrations of pigment as well as light and darker areas.

Yours,
Big Al

Good One Richard,

Here is some good information that you can pass on to your customers courtisy of Big Al. Concrete as a countertop material is just now becoming familiar to many homeowners. It has been around since the seventies and has been a favorite with modern designers and architects. Acceptance with the general public however has sometimes been a bumpy road. Concrete countertop materials and manufacturing processes have continued to evolve from a couple of guys in a garage using basic concrete and masonry supplies to state of the art facilities that employ products and techniques specific to the concrete countertop industry. As a result of this, there are many things that you should be aware of when you are considering concrete for your renovation or new construction project. A visit to a concrete countertop studio is a good investment in time that can give you a quick education on the manufacturing process and open the doors to almost endless possibilities.

Any size, any shape, any color is the mantra of the concrete countertop artisan. As you enter a concrete studio and production facility you may be overwhelmed by concrete displays, art objects and the many samples that seem to be everywhere. Concrete allows artisans to express themselves. This choice, this freedom to express yourself is where concrete stands alone as a countertop material. The samples are not your only choices but are a starting place for the imagination. Customers often bring color swatches, tiles, cabinet material samples or objects such as pottery or glass to help with color selection. Color samples can be made to order and taken to the job site to insure that the color is the right fit for the design.

Color variation may be the concrete's greatest strength but choice in shape and size is a close second. Unlike other solid surfaces, concrete countertops are made by artisans. Granite and synthetic solid surfaces begin their life as slabs produced in large factories and are then cut to the desired shape. On the other hand, the concrete production facility is often compared to the studio of a potter or sculptor. Organic shapes, drain boards and drain flutes, inlays and variations in thickness are standard fare for concrete countertops. You can be a valuable partner in design by suggesting or providing objects for inlays, sketching organic lines for edges or placing masks used in acid washed countertops.

The concrete countertop experience has an unequaled level of customer involvement. In fact the you may become a partner in design and manufacture. Concrete countertop manufacture is not a faceless operation where machines cut and grind prefabricated blocks but an operation where skilled craftspeople
nurture the countertop from concept to kitchen.

Easy John
You can relax, chances are that you and your customer are in no danger. We have been getting this question for a while now and when we first heard it we were alarmed. Big Al has done his homework and concluded that most of you out there with granite are in no danger. The problem is that most granite does not contain significant amounts of radiation producing minerals, like uranium. There are some exotic granites that do produce radiation.

There was much excitement when the early show produced a segment on the subject. You can watch it here. As you can guess, the granite and marble folks got pretty upset and saw their customers walking away. There has been a lot of finger pointing going on and some well meaning people putting out some wrong information on both sides of the issue.

Here is a good article from the Grey Lady that has some good information and links.

Big Al loves granite. When used along side concrete, each amplifies the natural beauty of the other. Big Al recommends that you have your granite countertops tested, just to be sure. If you aren't sure how to have your countertops tested, send us an email dang@alphastoneconcrete.com.

Wendy,

You and Jason should make sure that the piece will fit into the new space before the walls are closed up. Also be sure that you have proper support for the weight of the counter. At 2" thick it could weigh as much as 25 lbs. per sq/ft. Any part of the island that is cantilevered more than a foot should have additional support. I've made large concrete counters like this in multiple pieces incorporating varying thicknesses that were aesthetically quite pleasing. Is bigger always better?
Big Al

Dear Allen,
That's a pretty good idea. We've used many decorative additives to our mix over the years but never exactly what you are suggesting. I see no reason why it shouldn't work although I'm sure you are aware that you will have to grind/polish the surface to reveal the material that you add to the mix. By doing this you will also reveal everything else in the mix like sand and stone. Good luck with your project and send me a picture when you're done.
Big Al

Ok Pat,

Big Al is going to assume that you have new concrete countertops. Your care and maintenance instructions are going to depend the type of sealer that your concrete countertop manufacturer used on your project. Because the sealer is designed to repel liquids, you are really cleaning the sealer. Different sealers have specific instructions for the product. There are a few general rules for cleaning concrete.

Rule number one: Don't use any acidic cleaners. These include citrus based cleaners. They can damage many types of sealer and etch the concrete.

Rule number two: Be gentle. Mild soaps and detergents are usually adequate to remove most stains.

Rule number three: Clean up spills before they become stains. The worst case scenario is the morning after the big Cinco de Mayo party, with spilled margaritas and limes left on the countertops from the night before.

an ounce of prevention,

Big Al

Hi Sharon,
While granite and concrete are both solid surfaces and cost about the same their similarities begin to part there. Concrete can more easily and cost efficiently be fashioned into any shape or thickness because it is formed at the liquid state and not tooled. Concrete, the chameleon of solid surfaces, can be virtually any color. In fact the visual complexity of this material is endless and only bound by the imagination. Concrete is a renewable material and can be made of recycled materials. Ironically, concrete countertops can be made of granite as an aggregate.
Al

Wow Steve!
This is a big question and Big Al is going to give you a big answer. This is not only a question asked by customers all the time but, it is a question we ask ourselves every day. There is a growing number of companies crowing about their products and services being green. We approach these claims with caution when we buy our materials and plan our projects.

There are differing opinions on the environmental impact of concrete.
Concrete can be considered to be a green material for countertops when compared to other solid surface materials. That being said, all concrete countertops are not created equal as far as the measure they affect the environment. There are no hard rules on what is green and what isn't so, here are the things that Big Al considers when he determines whether something is green or not.

What is the carbon footprint of the project? Concrete has one dubious component, portland cement. There is a pound of carbon-dioxide for every pound of portland cement manufactured. The portion of portland cement accounts for about a quarter of the mass of the concrete used in our countertops. We can safely reduce this amount by thirty to forty percent by adding flyash or other pozzolans. Aggregates made from recycled materials such as glass, coal slag or reclaimed concrete will make the product greener. Manufacturing processes that reduce waste and energy consumption also will green up the project. Last of all, using a local material instead of something that is made from petroleum or is shipped halfway around the world is an rule of thumb in determining if a product is green or not.

green as you want it,
Big Al

Good one Dianna,
One and one half inch thick Concrete countertops weigh around eighteen pounds per square foot. Alpha Stone Concrete uses a light weight aggregate to keep the weight down and make our concrete products more environmentally friendly. Our concrete weighs about thirteen pounds per sq/ft. So a countertop that is twenty-five inches wide and eight feet long would weigh around two hundred and twenty pounds. Sink openings will reduce the weight by somewhere around forty to sixty pounds. That may seem heavy to you but we have seen old or inexpensive base cabinets support the weight with no problem. Base cabinets are basically a box, a structure that is very strong. Also, the weight is evenly distributed over the base cabinets. Any good template guy will inspect your cabinets to determine if there will need to be any reinforcing or modifications to your base cabinets.

Thanks for the weighty question,
Big Al

My dear Alissa,
Your problem is nearly solved because you still love your concrete counters. The darkening or patina that you are experiencing is probably due to an abrasion or break down in your protective sealer. Your concrete has absorbed water or oils which has caused it to change. The water will evaporate but the oils will remain. I suggest that you determine how your counters were sealed and have them resealed. The oils will continue to absorb and disburse over time but for now you might want to enjoy them memories of the activities that caused the change in the first place. It's better than a journal.

Up to my knees in concrete,
Al

Hi Jesse,
Cement is a primary ingredient of concrete. You know people ask me about "cement countertops" all the time and I never correct them. It's all right with me what ever you call them.
Concrete is made up of portland cement aggregate and water. Portland cement is made from limestone and sand or clay. Aggregate can be sand, stone, glass or just about any material that is non absorbent and does not degrade over time. For a good overview of concrete countertops click here.

Yours,
Big Al