Concrete Blonde: Frequently Asked Questions

Weight is only an issue for those installing the pieces. The concrete benchtops themselves are adequately supported on standard cabinetry and a stable sub floor. Lightweight concrete is available though it is never as strong or abrasive proof.

The desired thickness of your concrete benchtop is personal. Some choose 30-40mm in keeping with standard dimensions. Others prefer 65-100mm to capitalise on the feel of solidity and gravitational weight. The appearance of a (say) 100mm thick benchtop can be achieved without the piece being that thick throughout. The piece would be 40mm with a square set edge cast in 100mm. This allows for transport, ease of installation and undue stress on supporting cabinetry.

Holes for sinks, cooktops and taps, sloping draining boards and edge profiles are all cast in the form work to exact specification.

Pieces cast in factory are limited in dimension to the size of the high frequency vibrating table (3000 x 1200mm) on which they are cast. Over this they must be made on site. If site access is an issue they must be formed, poured, cured and finished on site as well. Considerably more control though is available in the factory. Here we cast face down on smooth formwork allowing the finished product to be completely flat and showing lots of life, dappling and aggregate ghosting. The in situ product will tend to be more hand made therefore beautiful in other ways.

Most colours and shades are available and are quite muted. All are achieved with inorganic light-fast pigments / oxides in the wet mix. Colours include: off white; light grey; grey; charcoal; bluestone grey; black; latte; chocolate; mulberry; ochre; marigold; yellow beige; pink beige; pink; drab olive; grass; taupe; aquamarine; cobalt

Concrete benchtops are incredibly inviting to the touch. It is the smooth and as soft as marble feel that most surprises the uninitiated. The general response is that's concrete?

Off-form refers to concrete cast against formwork. The finished product takes on the texture of the board it is cast against. For instance a concrete panel cast on woodgrain will have a woodgrain texture. At Concrete Blonde we cast face down on smooth mid sheen boards. The vibration and compaction process settles the aggregates (stones) flat into the face of the piece with a thin skin of cement covering them. When finished the surface, though completely smooth, shows the ghostings of the aggregates within. This tends to give the piece an enormous amount of life and movement (and abrasive resistance).

Occasionally we're asked to grind the surface to expose the aggregates much like terrazzo. This is an entirely different effect and stunning in its own right. Marble chips, granite chips, glass and metals can be used in the mix and exposed by the grinding. This will give an effect similar to the reconstituted benchtops on the market with their marble chips held in a coloured epoxy matrix.

Architectural concrete is far denser due to its construction techniques than other concrete. Though still porous, like natural stone, this feature of concrete allows atmospheric moisture to hydrate the cement forever, thus constantly hardening the piece. Some say Roman and Greek concrete is harder today because of this phenomenon. It is also for this reason that the surface of your concrete benchtop will over time vary its patina, taking on its environment, gaining depth of character, egg shelling and marbling.

Sealers come in two types. Those that are topically applied like a varnish and adhere to the surface creating a barrier and sheen. The other sealers penetrate the surface leaving a natural look and feel. It's these penetrating sealers that allow moisture to move in and out of the piece without leaving stains. Both types of sealers protect well against oils and dirt though acids such as vinegar and red wine can tend to lighten but not discolour the surface. If a totally impervious surface is what you require then concrete may not be for you.

Unlike natural stone, concrete doesn't have a grain. If struck hard it won't ripple-shatter a large circle or cleave off. The damage would be contained to the point of impact and can be easily repaired.

Unfortunately there is no simple pricing formula on a per square metre basis. Pricing depends primarily on the amount of labour and detail involved in the formwork, steelwork, pour, curing, manual handling, finishing, transporting and installing. Whereas the material cost is moderate it is the hands-on nature of the process that commands the final price. However, to give you some guidelines, it falls around two thirds the price of the comparable granites, marbles and reconstituted benchtops.

Floors are another specialist area in the structural and aesthetic world of concrete. I've been involved in the placing of decorative concrete floors though do not take on such projects in my own right. I'm happy to give an overview of the process and to suggest those who may be of assistance in the placing, grinding and sealing of one of the most stunning and serviceable floor surfaces around.