Reasons to Round Over Your Square Sharp Edges

It seems that people learn from infancy to associate right angles, flat planes, rectangles and squares with the buildings that we live and work in. Despite Buckminster Fuller’s efforts for decades to convince people that the geodesic dome is a superior structure, our architectural vocabulary is still based, to a large extent, on straight lines and 90 degree angles.

Perhaps the straight and the square symbolizes for us a comforting and civilized distance from the irregularities of nature, which, though often beautiful, can also be harsh and cruel.

Not surprisingly, most kitchens are filled with straight lines and right angles. Perhaps these spaces are softened occasionally by a gentler 135-degree angle or a curve here or there, but the overall straight and square look continues to dominate.

A countertop is really nothing more than a flat horizontal work surface used primarily for food preparation. That’s its function. Most countertops are, to a large extent, rectangular in shape or combinations of rectangles.

Sharp square corners and edges can lead to a variety of long-term problems with various types of countertops. In past columns, I’ve written several times about how square inside corners in appliance cutouts can lead to an increased risk of countertop cracking, especially with relatively brittle, homogeneous products such as solid surface materials. Similar problems can develop when a countertop wraps around an outside wall corner.

Although natural stone may be less prone to such problems, stone countertops can also crack at inside corners, especially when subjected to significant stresses. For that reason, it’s far better to create radiused inside corners, which are by their nature much more crack resistant when rounded appropriately.

Many architects and designers, especially those who favor a modern, industrial aesthetic, will specify square sharp edges and corners on countertops. I am reluctant in most cases to interfere with a designer’s vision, but flatly stated, this is a bad idea.

Form Follows Function

Louis Sullivan, the influential Chicago architect who is credited with originating the modern skyscraper in the late 19th century, famously said, “form follows function.” Actually, he originally said “form ever follows function” but the phrase was later simplified, and the meaning and applicability of Sullivan’s slogan when applied to the design of an entire building has long been debated.

When discussing the simpler and purer topic of how a countertop ought to be detailed, though, the logic is clear. Why select an edge detail that is known to cause problems when similar edge details that minimize such problems are available? Select a form that best serves the function.

Simply put, a square countertop edge is prone to chipping. A rounded or radiused countertop edge is far less prone to chipping. A tiny radius reduces chipping a bit. A larger radius reduces chipping even more.

The chipping is caused by glancing blows by heavy objects. A kitchen countertop is a functional work surface where heavy objects – pots, pans, cans and bottles – are moved about constantly. To best achieve its intended function, the form of the countertop ought to resist such damaging impacts.

This does not mean that all countertops ought to look alike or that there is no role for aesthetic design. But when a designer insists that the countertop ought to have square sharp outside corners, damage over time to those edges in a working kitchen is almost assured.

I see this sort of damage all the time, and one of the most common locations is along the edge of the cutout of an undermounted sink in a countertop made out of natural stone or quartz. Often, these countertops are just a year or two old, and look almost new except at the sink cutout. However, because this edge is almost square with just the tiniest radius, there will be several big ugly chips where heavy pans have hit the edge. When questioned about this practice, people in the industry often respond, “Well, that’s the standard undermount sink edge detail that stone and quartz fabricators do when no other edge is specified.”

I don’t think that’s a good enough answer. The “standard edge” ought to be a more practical edge, such as a radius of at least one quarter inch or larger.

Though the problem may be most common around sinks, it can also be seen on any square edge of the countertop, usually concentrated in the areas of heavy usage. We’ve fixed this kind of chip many times in my countertop repair business, but we would prefer that fabricators avoid problems for homeowners down the road by fabricating the sink cutout properly in the first place.

There’s an edge detail common to solid surface countertops that creates a similar chipping problem – and another problem as well. I am referring to the Roman ogee edge. That’s the classic edge detail with a little stair step at the top – a square outside corner, and a square inside corner, and then an elegant S-curve just below. It creates an interesting pattern of light and shadow, and looks great when it is new.

After a few years, though, the sharp outside corners are often chipped in many places, and the sharp inside corners are packed with dirt and grime that’s tough to remove. The countertop looks battered and grungy. Many times, I’ve had homeowners express the wish that they had selected a more durable and easier to clean countertop edge. A simpler, smoother ogee without the square corners is a nice alternative – an elegant look without the downside. Most stone fabricators offer a gentler ogee like this.

Safety Issues

The outside corner of a rigid cube is a pretty sharp and potentially harsh shape. Those of us who are tall and who work in various kitchens a lot have shared the unpleasant experience of accidentally smacking our heads against the corner of an overhead vent fan. It’s far more painful when that corner is sharp and square, as opposed to gently rounded. At such moments, one wishes that the geometric purity of the sharp-edged corner was moderated a bit. I’ll often fold a paper towel into a little cushion, and fasten it in place with masking tape until my work in that kitchen is finished.

A similar problem often results from fabricating sharp square outside corners on island and peninsula countertops, especially when the walk paths are a bit narrow. Many customers have told me that, far too often, they will accidentally bump into such corners, and that can be quite painful. Sometimes bruises result.

Fabricating these corners with a radius of half an inch or more greatly reduces the pain of an accidental collision. This seems so logical and so self-evident that it is surprising that so many countertops are made with these square outside corners.

Countertop fabricators, in my view, have the responsibility for considering how their products will perform over a period of many years. What looks great when brand new may not be practical over the long haul. Let’s be advocates for rounding over the square sharp edges whenever possible.