Maarten Zwartjes is a small terrazzo company that is specialized in the crafting of concrete countertops. He is constantly working on renewing his work with inspiration from international concrete-architects like Rudy Riccioti, Fu-Tung Cheng and Mark West. By following the developments in the concrete technology and applying them to his work, he is always searching for innovation. An example are the countertops made from polished concrete.

Because of these innovations Maarten Zwartjes offers a wide selection of products. In addition to the traditional terrazzo and concrete tabletops he also makes walls, bar tops and versatile concrete. You can ask for a noncommittal offer via email. Offers can almost always be made on the basis of building plans. If not then Maarten Zwartjes will come on a working  visit.

Maarten Zwartjes is associated with the NOA. On all the supplied work their  warranty conditions apply before delivery. He is a recognized floor-approbation company with the foundation 'Afbouwkeur'  This is how the quality and working method are measured every year.

Although Maarten Zwartjes is specialized in the making of terrazzo and concrete countertops on-location, he is also able to craft countertops in his workshop. Tops of 3 metres (10 ft. 7 in.) are also a possibility.
A big benefit of an on-location made countertop is that it always fits. Even if the walls are not straight or right-angled. The countertop always consists of one solid piece without seams. This looks way better in big kitchens. One disadvantage is that the proceedings on-location always cause some form of nuisance and need to fit in the timeframe of renovations.

Maarten Zwartjes is specialized in the making of concrete tabletops. But he also makes other concrete elements like floors and walls. The concrete has a tight and modern look and the manual crafting gives it a unique look.

Method

Concrete is a mixture of cement, sand and water. The concrete is poured into a mold, when it is totally cured it gets sanded. It is possible to do this at your location or in his workshop. By adding pigment it is possible to give the concrete different colors.

Making a concrete countertop

There are two ways to make a countertop upside-down: in a mold or pouring the concrete into a mold and smoothening it by hand. Both ways have a very different look and therefore different advantages and disadvantages

By upside plunging in a mold the mold is created first. The concrete in the bottom of the mold will be the top of the countertop. Therefore the bottom part of the mold has to be one solid piece. Otherwise there will be a seam on the surface of the countertop. And this is why there is a limit to the size of the countertop. But by doing it this way the countertop's surface is very smooth and equal.

The other way to make a concrete countertop is to pour the concrete into a mold and smoothen the top manually. If you do this the surface keeps more structure and gives the surface a more 'raw' look. the result of this is that the top has a more robust and artisan look. Another advantage of this that larger countertops are possible without seams.

Finishing touches

After about 2-4 days the concrete is hard enough to be sanded and polished. This is done with a diamond tipped stone barn until the surface is extremely flat and shiny.

Impregnating the concrete

Concrete is made with natural porous. Because of this sanitizing the countertop can cause spots and stains. That is why it is important to impregnate the countertop after scouring it.

Maarten Zwartjes has, after testing in his workshop for a long time, discovered that the newest nano-impregnating medium Lithofin is also the best one. It draws into the countertop without  forming a visible layer on the surface so the countertop keeps it's natural look.

Yet even with this impregnation, protection against stains is not a hundred percent safe. If dirt remains on the counter for too long it still creates stains. Especially acids can cause staining as concrete is a calcareous product. On request Maarten Zwartjes can therefore use a two-component polyurethane sealer. This excludes the countertop completely from stains, even against acids. However, this is known to leave a coating on the surface. A true concrete purist finds it less attractive in terms of appearance.

Putting together a good mix is critical. It's the little nuances that make the difference, see the samples above. In addition, the possibilities are endless. Some clients, such as architects or designers know exactly what they want. Their choice reflect their particular style.

Each terrazzo-worker also has his or her own recognizable style. Maarten Zwartjes finds a mixture that consists of one kind of stone beautiful. The good thing about terrazzo is that you can determine  the composition and the color itself. If desired, a different kind of sample can be made for each seperate client.

Also, you can make concrete countertops in many different colors. For this, Maarten Zwartjes uses the Bayferrox metal-oxides made by Scholz. These pigments can be mixed. The good thing about these pigments is that they are resistant to the alkali in the cement and the colors won't fade.

Another way to give the concrete a color is to use colored sand. If you do this, stone is mixed with natural white cement. So in terrazzo it's possible to use the same stone for the stone chips as well as the sand in the cement.

Maintenance Information

Information from Lithofin for maintenance.

Drawings about underlayment

Drawings for concrete underlayment.

Drawings for wooden underlayment.

Terms & Conditions

Maarten Zwartjes works under the following terms & conditions:

General consumer conditions for completion companies (in dutch)

General conditions business traffic for completion companies (in dutch)