From Solid Surface Countertops to Concrete: What you need to know

Many countertop fabricators, whether they offer natural stone, engineered stone, solid surface or a combination, are recognizing the consumer demand for greener, more custom products such as concrete. As a countertop fabricator considers adding custom concrete countertops to his or her offerings, there are a number of practical considerations such as startup costs, learning curve, profit margin and the logistics of incorporating concrete into shop space and production process flow.

Please note that this article addresses only custom-made concrete countertops, not pre-made concrete slabs such as IceStone and Vetrazzo.

Startup Costs

Adding concrete countertops to your offerings incurs low startup costs. There is very little equipment to buy. The largest equipment purchase is generally a concrete mixer, at about $2000 – $3000. Most of your existing grinding and polishing equipment can be used. Typically concrete countertops are hand processed using hand held one-head or three-head grinders, but a radial arm polisher can also be used.

It is important to understand, however, that the diamond pads used for grinding and polishing concrete are different from those used for granite. Unlike stone, which is uniformly hard, concrete consists of hard sand and aggregate bonded with relatively soft cement. This is extremely abrasive to diamond pads, and will tear the diamonds out of the binder on typical diamond pads, resulting in much faster wear. It is more economical to purchase diamond pads specifically designed for concrete.

The materials needed for custom concrete countertops are very inexpensive. From-scratch mix ingredients, along with all the consumables such as diamond pads, forming materials and sealers, generally cost only about $8 to $10 per sq ft of finished 1.5″ thick concrete. If you use bagged mixes, material costs will be significantly higher.

Learning Curve

Although templating and installation are almost exactly the same for concrete as for stone, concrete is cast, not cut. For shop employees who are accustomed to cutting shapes out of slabs, creating forms and molds can be challenging because it is a different way of thinking. Add to this that precast concrete countertops are typically cast upside down, and you have the potential for mistakes.

Another steep learning curve involves working with the concrete mix, whether you use a from-scratch or bagged mix. Precision is extremely important, with differences as small as a gram sometimes having significant consequences. It is also important to understand technical aspects of concrete such as water/cement ratio, water reducers and admixtures, because the behavior of concrete depends on many factors such as humidity and temperature.

Profit Margin

Custom concrete countertops command a high price, generally about $80 to $120 per square foot or higher, depending on your market area. Due to the low startup costs and low material costs, the profit margins can be very good.

However, you need to be acutely aware of your labor costs. Custom concrete countertop generally require a high amount of hand labor, although there are ways to optimize and automate this, which will be discussed later in the article. As with other materials, the biggest barrier to high profit margins in concrete countertop manufacturing is mistakes and re-dos. Avoiding re-dos in concrete countertops requires all of the normal quality control procedures you have in place, plus a good understanding of concrete as explained above.

Shop Layout

Even the fastest casting and curing methods for concrete can require that a concrete countertop project take up space on casting tables for at least half a day. Casting table times are more typically around two days. You will need to allocate space in your shop for casting tables to accommodate the concrete slabs during forming, casting and curing. You will also need space for the mixer and mix ingredients.
It is possible to install a racking system to store concrete slabs while they are curing, however moving newly cast concrete slabs must be done with great care.

Process Flow

Templating and installation of concrete are almost identical to stone procedures.

Most concrete countertop shops create physical templates manually, then hand build forms around the templates. They use materials such as melamine and foam to create the forms along with sink and faucet knockouts.

Digital templating is rarely used with concrete countertops because most concrete countertop-only shops simply do not have the equipment.
If you do have a digital templating process that feeds into your CNC machine, you can take advantage of this to greatly streamline the templating and forming process. Use your existing digital templating process, but then instead of using your CNC machine to cut countertop shapes out of a slab of stone, use it to cut a hole out of a slab of foam. This will create your form quickly and automatically.

Installation of concrete countertops is very similar to stone. The countertop slabs are transported vertically, and can usually be carried using the same equipment as stone. The biggest difference in installation is the seam filling. Sanded acrylic tile caulk is used instead of epoxy, and cleanup must be done with a sponge, not a razor, especially if a topical sealer was used on the concrete. Also, the underside of an undermount sink opening in concrete must be sealed to prevent contact of the concrete with the silicone used to fill the gap between the countertop and the sink. If silicone comes into contact with bare concrete, it will react and form an oozing, oatmeal-like consistency.

The time in-between templating and installation is very different. As mentioned before, concrete is a high touch process requiring a lot of hand work. It requires forming, mixing, casting and curing time that do not come into play with stone and solid surface. As mentioned above, it is possible to streamline forming by cutting forms out of foam on your CNC machine, and to use radial arm polishers instead of hand held polishers.

Conclusion

By understanding all of these considerations and focusing on employee education, quality control and carefully thought-out procedures, you can profitably add concrete to your business. The benefits go beyond pure profit to building competitive advantage through diversifying and differentiating your business with this beautiful, unique product.

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