Whangārei Boys' High School
Concrete Etching and Stencilling

Whangarei Boys’ High School wanted architectural detailing that would not fade, peel or need repainting over time, and the solution the architect specified was to cut the design directly into the concrete rather than apply it as a surface finish. Painted graphics wear under foot traffic and weathering, and on a school site with constant use, that wear shows quickly.

BlastOff carried out the work using concrete stencilling, setting out and masking the pattern against the architect’s drawings before sandblasting the design into the concrete. Every panel was checked against the drawings before the masking came off, since there was no scope to correct visible errors once the concrete had been blasted. The finished pattern reads as a contrast in texture between the treated and untreated concrete, and because that same blasting process roughens the surface, the stencilling also improves slip resistance underfoot in the areas students walk through daily.

For schools, councils and property owners considering similar architectural detailing, the key advantage over painted graphics is that the finish is part of the substrate itself, so there is nothing to maintain beyond the concrete. That makes it well suited to high-traffic public and education sites where recoating cycles are impractical or costly. A scoping conversation for comparable work should cover the accuracy of the supplied drawings, the condition of the existing concrete, and how the depth of blasting will affect both the visual contrast and the underfoot texture, since getting that balance right is what determines whether the finished pattern reads clearly and performs safely for years to come without any applied coating standing between the design and the weather. A trial panel is a sensible step before committing to a full-scale design, giving the school and the architect a chance to confirm the finished contrast and grip firsthand.