Cutting it Fine

The Evolution of Millwork, Trim and Cladding

“Moldings are honorable things which are not to be treated casually or copied blindly.”
-Charles Howard Walker (architect, author and teacher)

No matter how well-built a structure might be, the devil is truly in the details. From exterior cladding to interior millwork and trim, structures need to be not only well-designed and constructed, but pleasing to the eye.

To a client, there are few things as irritating as haphazard work, like a section of uneven crown molding, or trim around a door or window that looks off. Despite new techniques, technologies and materials like Medium Density Fiberboard (MDF), extensive training in woodworking is essential to ensure quality results.

With at least three to four years of formal education and experience with instruction on the job needed to be a skilled carpenter, trainee carpenters put in thousands of hours both in class and at work.

From developing math skills to learning which tools to use, safety training, and interpreting drawings and blueprints, carpenters have to be dedicated to accurate work whether framing a wall 16 inches on center or safely operating costly machinery like wood lathes, radial arm saws, joiners, drill presses and routers.

Woodworking remains a trade combining technical know-how with artistry while bringing to life the vision of the builder, architect, and customer.

Past meets present
Decades ago, decorative designs and moldings – a type of trim known for its elaborate details – were made from solid wood, stone, or plaster. Today, many of these architectural elements are precast from plastics like polyvinyl chloride (PVC), EPS, expanded polystyrene, and Styrofoam, which can mimic the appearance of stone.

Used both inside and outside, trim, molding, and even columns can look exactly like wooden hand-carved pieces from yesteryear, yet do not weather, crack or splinter. They resist termites and other insects, and last for years. Depending on the style and era the client chooses, these accents can include Victorian stair brackets, ornate leaf-themed rail moldings, Art Deco-inspired details, finials for staircases, rosettes, corbels, plinths and more, all pre-made, primed and ready for painting and installation.

Like many other products, PVC is credited to more than one inventor. Its origins go back to French chemist Henri Victor Regnault who, in 1838, inadvertently created PVC in a lab – and not recognizing any commercial value in the white substance, neglected to secure its huge benefits for himself by taking out a patent.

Others followed, including German “father of vinyl” Eugen Baumann, chemist Friedrich Klatte, and American Waldo Semon. Devising new methods to make PVC less rigid, Semon produced a PVC that was an economical alternative to wood and moldable to any shape.

This discovery led to the production of PVC trim which did a pretty good job of what wood had done previously – but instead of taking hours or even days to be carved and shaped by hand with knives, chisels, and planers – was made in injection-molding machines in minutes.

The technological advances in woodworking machinery remain some of the most important in history, since it affects every aspect of our lives, from the houses we live in to the places we work and the furniture we use every day.

Without a doubt, the most important early invention for the field of woodworking was the saw, which led to the development of the first sawmills in Europe in the 1400s. Early advances, such as Sir Samuel Bentham’s planing machines with rotary cutters and bevel sawing machines (patented in the 1790s), were primitive by today’s standards, but they sparked countless other imaginative leaps in toolmaking.

Before too long, more essential devices appeared – for planing, molding, and mortising, particularly in the 1800s and coinciding with the Industrial Revolution. Others, including band saws and scroll saws, soon followed.

From wood to synthetics
Just as millwork has evolved over the centuries, so has cladding. Defined by Merriam-Webster as ‘Something that covers or overlays,’ cladding’s origins go far back in history, but its purposes remain the same: to improve the appearance of a building, and to provide additional insulation. Adding an extra layer of protection for structures, many of today’s residential, office, condominium, stadium, commercial and industrial construction projects feature cladding which requires little maintenance.

Historically, cladding was crafted from woods like oak and elm. Evidence suggests the earliest use of the material goes back to 500 AD. Thin strips of wood called “clapboard” were applied to exteriors of churches to protect them from wind, rain and snow. As technology advanced with the Industrial Revolution beginning around 1760, machines gradually took over the milling of wood for cladding, replacing slow, costly hand milling.

While other natural materials such as stone and wheat fibers have been used for cladding, these have all pretty well been replaced by brick, terracotta, metal, synthetics, and hybrids such as precast concrete, glass-reinforced polyester, unplasticized Poly Vinyl Compound (uPVC), weatherboard, glass, and glass-fiber reinforced cement.

While each has its advantages and disadvantages, with particular importance given to cost and ease of installation, the function remains the same.

Burning question
Historically, one of the drawbacks of wood cladding was risk of fire, and manufacturers had to treat wood with fire-retardant salts or paints. And still, as much as cladding is meant to protect structures, it sometimes does the exact opposite.

While Aluminum Composite Panels (ACP) have existed since the 1960s, they did not become widely used until the early 1990s “in residential and commercial buildings to improve architectural performance and reduce costs,” according to The past, present and future of external cladding, a recent document prepared by Australia’s Longitude Insurance.

Aluminum Composite Panels consist of two aluminum skins, bonded to a core made from 100 percent polyethylene (PE), aluminum honeycomb, or Fire Retardant (FR) composites comprising mineral wool and PE. In some cases, these types of cladding allow fire to spread, as seen in Liverpool in 1991, Scotland in 1999, and other locations including China in 2004, France in 2010, and Dubai between 2012 and 2016. None of these incidents were fatal; tragically, the same cannot be said of the Grenfell Tower fire.

On June 14, 2017, fire broke out on the fourth floor of this residential building in West London. Triggered by a malfunctioning fridge-freezer, fire spread quickly and the 24-story structure was soon engulfed in flames. Despite the efforts of over 250 firefighters and dozens of fire trucks battling the inferno, 72 died as a result. At the initial Grenfell Tower Inquiry – which is still ongoing at the time of writing – it was determined that the fire spread along the east façade within minutes via the exterior cladding.

According to the public Grenfell Tower Inquiry: Phase 1 Report Overview, the primary reason that the fire engulfed the building so rapidly “was the presence of the aluminum composite material (CAM) rainscreen panels with polyethylene cores, which acted as a source of fuel.” This allowed burning polyethylene to drip down and ignite, accelerating the fire even more. To make matters worse, “polyisocyanurate (PIR) and phenolic foam insulation boards behind the CAM panels, and perhaps components of the window surrounds, contributed to the rate and extent of vertical flame spread.”

Media investigations soon revealed that other fires, such as 2014’s Lacrosse Tower in Melbourne, were also fueled by flammable cladding. Fortunately, no one died as a result of that conflagration.

While computer programmable CNC machines and molded resins have revolutionized how cladding and millwork is made, there is no substitute for highly skilled carpenters producing custom work. From basic baseboards to door frames and stunning window casings to extravagantly carved wall paneling, molding, trim and other decorative accents are not only a reflection of the pride we have in our homes, but a reflection of our tastes.

November 24, 2020, 10:04 PM EST