Semi-detached homes were once the dominant style of urban dwelling in Canadian cities and continue to make up most of the housing stock in older neighbourhoods. Though their specific styles vary with the region and era, they all share a core design typology that has quietly endured the past century, even while changing construction methods and development patterns have supposedly rendered them obsolete. If they are appreciated at all, it is usually for the quaint heritage character that they lend to a streetscape. They are frequently overlooked completely in discussions of residential architecture, due to their age and commonness. But when we examine them more closely, the fact that they have endured for so long and in such abundance might be indicative of something special.
My firm has been examining them very closely for years, as the bulk of urban development work moves from the suburbs to the city centre. Faced with tightening urban growth boundaries, large-‐scale developers’ monopoly on greenfield projects, and a general cultural shift towards urban intensification, today’s environmentally-‐conscious custom home builders are experiencing a change in professional focus. Instead of developing showcase homes on pristine undeveloped lots, the green building industry is increasingly looking at existing urban areas and concentrating on adaptive reuse.
The basic principle behind this movement is that even a cutting-‐edge sustainable building represents a major carbon footprint, due to the materials, manufacturing, and construction work inherent in all new builds. As an alternative, any opportunity for adaptive reuse is enthusiastically pursued. New buildings should be designed for flexibility, in order to outlive their original function and provide future generations with an opportunity to reduce material waste. Likewise, when we inherit existing buildings that were originally designed for resilience and versatility, we strive to take advantage of them. There is no need to bake new bricks if the brick walls made 100 years ago are still standing and remain useful. We can avoid using new lumber if we can find old lumber that already serves our intended purpose.
Some of the older buildings we encounter can be effectively retrofitted, while others are consigned to the wrecking ball when their owners’ needs outpace them. Some rare examples are remarkably suited to today’s urban environment, and can be conveniently upgraded with minimal waste. The best example we have found is the humble bay-‐and-‐gable row-‐house. These old houses are simple to renovate, employ numerous sustainable development principles, and deserve a larger spotlight than they have generally received. Focussing some attention on these classic brick homes provides great insight into the state of the industry today, while also highlighting an under appreciated triumph of past generations.
The Original Context
In Southern Ontario and most of United States, well-‐preserved 19th century townhouses are fairly easy to find. Their ornate red and orange brickwork is near-‐ubiquitous in urban Toronto, representing the majority of low-‐rise housing in the Annex, Kenginston Market, and Cabagetown among otherbooming areas. Hamilton’s Corktown almost exclusively features bay-‐and-‐gable housing of this type. They served as the original suburbs, built before the rise of the automobile, and employing principles of transit-oriented development out of historical necessity. High density, low-‐rise homes with minimal frontages were required to achieve compact urban development alongside major streets and trolley routes.
Behind the superficial variations in architectural style, these homes are all remarkably similar in appearance and structure. San Francisco’s ornate “Painted Ladies”, New York’s Brownstones and Cabbagetown’s austere orange facades hide underlying assemblies that are nearly identical. The front door sits alongside a prominent window into the living room.Smaller windows on the second and third floor provide lighting into the more private areas of the home. More often than not, there is a half-‐flight of stairs leading up to a small porch, and another one down to a well-‐lit basement. About half-‐way back, the homes narrow by several feet to create a light well that permits windows into the central rooms. This arrangement is mirrored in the neighbouring homes.
The exterior walls and interior unit separations are sturdy fireproof double-‐brick. Basic wood floor joists span the short distance between them. The interior partitions are basic wood studs, easily relocated. Original walls feature lath and plaster sheathing, but modern drywall is encountered more often as a result of past renovations. Straight-‐run stairs face the doorway, simply constructed but often elaborately decorated. Living and dining space is typically located on the ground floor, with bedrooms on the second and third.
The roof almost always follows a basic template. A steep-‐walled attic space sits at the front of the house, usually extending about half the total depth, with a flat roof over the remaining portion of the second storey. Amazingly, many of these homes still feature an unused expanse of tar paper over the flat roof, even though the myriad of potential uses for the space are obvious to most owners. Besides the potential to salvage useable square footage for a minimal cost, the flat roofs can serve as ideal staging areas for the hardware required by green retrofits.
Many Opportunities, Few Challenges
Nearly every aspect of this basic design makes it exceptionally conducive to adaptive reuse. Most of these homes have already seen many changes over their long lives. Modern bathrooms were added in the late 19th century, homes were wired in the early 20th, kitchens were opened up in the 1950s and 60s, and home offices abounded in the 90s. Bedrooms and ensuite’s are constantly being added, expanded, or reduced in size as different families come and go. Some of these historic brick facades conceal sparse modern interiors, while others still boast garish cabinetry and tiles from 50 years ago. Often, owners will strip the plaster from the interior walls to expose the bare brick, which is especially fashionable at the moment. In the future, it may be covered again.
In other cases, more radical change is pursued. Basements can be sunk to accommodate a secondary suite or recreation room where a massive coal-‐burning furnace stood a century ago. Small third-‐storey spaces can be extended onto the flat roof beyond without affecting the outward appearance of the home.
The beauty of the traditional framing lies in its resilient simplicity, creating a surprisingly modern flavour of functional minimalism in these Victorian homes. More often than not, the space between the century-‐old brick walls are spanned by equally ancient lumber, requiring no intermediate support. This means that interior partitions can be moved and rearranged as the owners see fit. Even our “full gut” projects tend to leave the floor joists intact, which is a rare luxury. Interior renovations are simple, cheap, and low-‐impact. The bricks always stay in place and continue to serve their original function, which ensures that the carbon cost of a conversion will always remain far below that of a new build.
These homes were not necessarily designed for sustainability, it was created by accident. Brick party walls were simple to build, fireproof, and strong. Their thermal mass, reduced heat loss, and long-‐term resilience are fortunate by-‐products. Compact urban development was a necessity prior to the invention of the car. We can appreciate these things far more today than 100 years ago, but we can also go further to optimize the efficiency of these homes. Just like how they were once retrofitted to use electric lighting instead of gas, the current marketplace is seeking sustainability upgrades.
Renovation over Demolition
Just like all the past renovations these homes have undergone, the simple and sturdy construction makes our modern work easy andrelatively affordable. In particular, the flat roofs offer great potential, and frequently serve as a starting point for all subsequent work.Usually, this takes the form of a third-‐ floor addition or a new outdoor area.
In the current real estate market, homeowners generally expect more living space than they did in the past. This is generally attributed to an abundant supply of suburban homes, with all their inherent inefficiencies, setting the standard. Victorian houses on small urban lots don’t offer the same interior volume. However, the builders did the next best thing by leaving us an obvious space to expand into, with the floor joists already in place.
These third-‐floor additions can create extra room for the spacious master bedrooms, ensuites, or extra bedrooms that today’s homebuyers expect. Conveniently, the sturdy load-‐bearing walls and floor are already built. Most surrounding homes are a similar height, so these additions can feature clerestories or broad windows that take advantage of their elevation to achieve some degree of passive solar heating – a rarity in urban homes. If the new interior design is particularly modern, we like to propose solar chimneys coupled with new interior voids to implement a system of passive ventilation-‐ raising air up through the home while letting light diffuse down. Even these more intricate additions are uniquely low-‐impact, because the resource-‐intensive job of creating foundations is unnecessary and the short joists spans ensure that no steel is required.
When the existing interior space is adequate for the client’s needs, owners like to use the roof as an outdoor amenity space. A rooftop patio, with planters or a pergola, effectively doubles the home’s outdoor green space while reducing runoff. A full green roof can take this principle a step further, and the load-‐bearing walls are usually more than sufficient to carry the extra load.
Other potential uses of the roof space are strictly functional, such as installing solar panels. The flat surface is an ideal for this purpose, exposed to sunlight and concealed from the ground. Solar water heaters also frequently inhabit this rooftop real estate. The existing capacity for extra loading on the walls and joists make hydronic in-‐floor heating practical, especially when paired with a heater on the roof.
New heating systems are best implemented alongside improved insulation. This is a less glamorous aspect of green design, but especially important in Canada. As with all other aspects of renovation, these townhouses are very conduce to having their thermal performance upgraded. As mentioned above, one or both of the long brick walls faces a neighbour. They provide thermal mass, and create no significant heat loss. Only the narrow walls at the front and back need to be insulated, along with the roof. With this reduced work area, owners are willing to invest in high-‐performance insulation for those surfaces, which will still cost far less than installing standard batts in a new detached home. When compared to the price of retrofitting detached houses from the same era, with their balloon framing, thin walls, and massive air leakage, the contrast is even more dramatic.
Green Buildings of the Victorian Era
Not surprisingly, alterations to these townhouses are almost always minimal and superficial, while the unobtrusive core structure endures unchanged. There is rarely any need to change it. The interior layout can be converted from a single home, to apartments, to an office, and back to a home without ever replacing the original floor joists. This style of home has lasted so long because they are built to be flexible and evolve over time instead of being demolished and rebuilt. Their resilient design consistently wins the admiration of modern builders as they face challenges that the original architects could never have predicted. This adaptability and robust construction means that their current owners love them, and they are exceptionally fun to work on.
Most importantly, they illustrate how sustainable building and efficient lifecycle design aresurprisingly common and well within the reach of most homeowners. Homes can exemplify these attributes while still being remarkably commonplace, simply designed, or even mundane. When we work on new builds, we try to keep this example in mind, striving to create designs that are not only functional and appealing today, but are versatile and resilient enough to endure far into the future like these homes have using the resources available today to improve them.