With irreverent apologies to Joe Cocker – who lays that number down so smoothly (Ha! Joe and smooth in the same sentence)  that anyone would be dissuaded from total abandonment…

Base form ready to pour

When we create integral sinks in a single wet cast pour, that is, using a very flowable concrete which fills the form and self-levels, it is necessary to work with a form that is watertight and able to withstand the significant hydraulic pressure to which it is subjected. If you incur what is termed a “blowout” in the middle of a pour, it is difficult, if not impossible, to salvage the moment and all the effort of building that single-use mold is lost. Back to square one; not a pleasant situation and certainly not a profitable one to those in the biz. It has happened to everyone at some time. It’s a lesson which is learned rather quickly and stashed away in the “never gonna skip that step again” files…

Hat form in place atop base

When doing a three dimensional pour such as an integral sink bowl (or two!) built into a concrete countertop, a two part form is constructed. The lower form might be termed the base, the upper is often called a hat or cap form. Both are built carefully ahead of time, mated to each other and shaped/caulked/drilled so that they are completely ready to be pressed into service as the pour commences.  Nota bene: Wet concrete waits for no man – so there are no opportunities to insert a missing step while in the heat of the moment. The lower base form is filled with the fresh concrete to its upper edge, vibrated for consolidation and air removal, and the hat mold lifted into place and screwed down quickly. Then the sink cavity (all upside down and backwards remember!) is filled to its upper extremity, consolidated, and the pour is wrapped up. Performing this process with two discrete colors makes it even more challenging, as one need to be careful not to contact any errant surfaces which would muddy the transition. This creates a very unique look however, possible only with the dynamism of precast concrete. A current project (showcased here) was cast in a dark grass green pigment for the body of the concrete countertop and snow white rectangular sink bowls. Definitely NOT “off the shelf”.

Hat form's white concrete placed

The resulting bi-color casting