Historic sidewalk prisms ( 3" purple glass squares) dating from the early 1900s are in place at seven locations in Victoria, British Columbia. Though thousands of pedestrians walk over the glass grids each day, few notice or fully appreciate these wonderful heritage features. There has been little information, no map, sign, or list of locations and no complete inventory of sidewalk prisms available. This report aims to fill that gap.
A page of background information is followed by an inventory of Victoria's sidewalk prisms with photos of each location.
A short assessment of damage and repairs illustrates how the prisms are being lost, one by one, as they are replaced by concrete and other materials.
Three recommendations to better preserve and protect these heritage features are presented and three proposals to increase awareness and promote sidewalk prisms as a downtown attraction. The report concludes with recommended websites and possible prism glass suppliers.
In the early days of Victoria, most downtown basements extended to the curb. The space under sidewalks provided storage areas for merchants and access from outside the building to deliver coal and freight. The cut-away drawing above shows a delivery and how prisms provided needed light below. (Illustration courtesy of Ian Macky)
To redirect sunlight from above into dark basement areaways, square glass tiles with horizontal prisms on the underside were installed. In the 1800s, the glass blocks were set in cast-iron grids. After 1900, most prisms were embedded in reinforced concrete.
The glass was clear when first installed and slowly turned a striking purple colour because manganese, used in the manufacture of glass from 1900 to 1914, oxidized in sunlight. The purple colour of Victoria's glass prisms indicates they were manufactured before 1915.
As recently as the 1970s, hundreds of thousands of sidewalk prisms stretched down Government, Yates and other downtown sidewalks. As streets and sidewalks were torn up and rebuilt, most prism grids were removed. Not all were destroyed: some were saved and remain stored in the Garbally Public Works yard. (Photos of the stored panels and a sample prism are provided at the end of this report.)
"Sidewalk Prisms" are listed in the City of Victoria Downtown Heritage Registry. "We try to preserve the sidewalk prisms as a decorative feature," Heritage Planner Steve Barber explained. According to Barber, the city carefully removed prism grids and re-installed them on Douglas Street and Fort Street during sidewalk improvement projects. Hector Furtado, Manager, Streets Division, pointed out a special effort was made to preserve prisms in front of Willie's Bakery on Johnson Street, as well.
As of May 1, 2006, there are 11,155 intact sidewalk prisms left in seven downtown locations. An additional 673 glass blocks are missing, damaged, repaired or replaced with other materials.
Total intact glass blocks on three sidewalks: 8138
-- Total currently covered or replaced with concrete, asphalt, grout or metal
grates on the three sidewalks: 248
-- The sidewalks around the Yarrow Building--on Broughton, Broad and Fort--
account for 73.5% of the surviving intact glass blocks in the city.
This is a crucial area to preserve.
-- The Fort Street under-sidewalk areaway has been filled. The two areaways
which remain, under Broughton and Broad Street sidewalks, provide
a unique opportunity for the city to illuminate purple glass
from underneath at night.
624 Broughton St. to the corner
Trucks unload heavy material on top of prisms at Fort Street at Broad. A parking meter and a street sign were erected in sidewalk grids, displacing four glass prisms. Two grey postal boxes are parked on top of glass blocks in another nearby grid, as shown in the above photo.
The areaway under the Fort Street sidewalk prisms has been filled in.
Pedestrian traffic, damage from vehicles and deliveries and environmental exposure have taken a toll on Victoria's sidewalk prisms. Heavy trucks back up onto prism grids and unload heavy material at Fort Street and Broad. At the same corner, a parking meter and a street sign were installed in prism grids, replacing four glass blocks. Two heavy grey postal boxes are parked on top of prisms in another nearby grid. Two outdoor cafes (714 Fort St. and 1114 Blanchard) position metal chair and table legs directly on top of glass prisms.
Hard working and well meaning city staff do their best, but are not trained in preservation methods and techniques. Through the years, city workers have filled cracks and spaces with materials at hand: concrete, asphalt, grout and square metal grates. New prisms are needed to replace 484 missing or damaged glass blocks. A specialty glass supplier of replacement prisms has not yet been found.
1. Finding a specialty glass manufacturer to supply replacement glass prisms is essential. Ideally, every broken or damaged prism found in Victoria sidewalks would be replaced immediately with a new one. A special program is needed to replace the over 600 damaged or missing prisms accumulated through the years with new glass blocks. Consulting with other cities and heritage specialists to find a supply of replacement glass prisms is a key strategy. A company spokesperson for Blenko Glass, of West Virginia, who supplied prisms for a New York City restoration project, believes they could supply Victoria's prisms. One of Victoria's glass blocks must be sent to them for examination. Contact information for that supplier and two other potential suppliers is provided at the end of this report.
2. Consulting with other cities and heritage specialists on the best methods, techniques and materials to repair and preserve sidewalk prisms is important. Others cities have experience in restoring sidewalk prism grids. For example, after a truck backed over prism panels near Seattle's Smith Tower, the panels were restored and reinstalled. A description of that work is posted on the internet and a glass supplier named. Sydney, Australia began a "pavement light" restoration on February 20, 2006. The last step in their project will be illuminating prisms from underneath.
3. Protection of heritage glass prisms should be considered when selecting loading and unloading zones for trucks, granting permits for sidewalk business activities on top of prism panels and erecting signs or other installations.
1. A brochure describing downtown sidewalk prisms is needed. The prisms are not mentioned in tourist literature and many residents are not aware of prism locations. The "Walk Downtown Victoria" brochure does not mention them either, though walk #3 includes two blocks with prisms underfoot. The photos and information in this report can be used by the city at no cost.
2. Interpretative signs explaining the history of sidewalk prisms should be posted near a prism site to inform residents and tourists.
3. When sunlight streams through sidewalk prisms into basement areaways, the purple glass looks spectacular (see first photo). Only a few maintenance men see that sight from below. A similar striking view could be enjoyed by everyone standing on the sidewalk if lights are installed below and connected to come on with street lights every night.
Illuminating the purple glass squares from below on two sides of the Yarrow Building (Broad Street and Broughton Street sidewalks) would add a striking new attraction to downtown. Those two sidewalks hold over 5,600 intact prisms. Areaways underneath are open and accessible (the Fort Street areaway has been filled); if they are filled in the future, spaces could be left to service the lights.
Victoria's glowing purple sidewalks would provide a unique new downtown attraction while highlighting a significant architectural and heritage feature at the same time.
The following comprehensive website covers all aspects of prism glass, provides information on Luxfer tiles and sidewalk vault lights (sidewalk prisms) and photos of sidewalk prisms in Astoria and Seattle, Portland, Chicago, San Francisco, San Diego and other cities.
This next website presents a detailed description of the recent reconstruction of sidewalk prism panels in Seattle. Called "Preservation Tech Notes Historic Glass Number 2, Repair and Rehabilitation of Historic Sidewalk Vault Lights," it is posted by the Technical Preservation Services, National Park Service, U.S. Dept. of the Interior. You can scroll to the bottom of each NPS webpage to access the Introduction and four more webpages.
The dimensions of the sidewalk prisms in Victoria sidewalks, according to Hector Furtado, Manager, Streets Division, are "approximately 75 mm square and 35 mm deep with 3 directional prisms" on the underside. He found no markings or labels which identified the manufacturer.
In answer to my inquiry, Blenko Glass official Donald Lemley wrote on March 9, 2006 that they can probably provide replacement prisms. The City of Victoria must send one of our glass blocks for examination. Lemley wrote: "We make the replacement circles for the city of New York for their sidewalks. We regularly cast glass in tiles in over 500 colors so I am sure that would not be a problem. Please call me here at the factory." His email address: firstname.lastname@example.org
This company does historic restoration and reproduction of sidewalk vault lights (prisms).
I spoke with Gary Bolt, one of the owners of Starfish on March 17. Though the company doesn't usually do this kind of work, he said it was possible they could make steel molds and produce replacement prisms. He requested a sample of Victoria's prisms to examine before committing to the project or giving a price.
Ten concrete prism panels salvaged from city sidewalks are stacked in the Garbally Works yard. The panels, shown in the first two photos below, could be reset into sidewalks in the future. Hector Furtado, Manager, Streets Division, recognizes the panels are valuable; he makes sure the old pile is saved whenever the Garbally Yard is cleaned up. Though thick dirt has accumulated on top of the panels over the years, light still shines through beautifully when viewed from underneath (see photo three).The concrete panels contain special metal frames which hold prisms in place, as shown in photo four. In the last three photos, Hector Furtado displays a prism recently cut out of a panel stored in the yard. He will send the prism to several specialty glass supply companies to examine in order to determine if they can manufacture identical prisms and to quote prices.
On May 24, 2006, city staff welcomed 800 school students to the Garbally yard annual Open House. Among the outstanding displays was a prism panel skillfully set up so it could be viewed from both sides by groups while a city worker explained the history and function of the prisms. It was a superbly organized Open House, with groups of students moving smoothly from one interesting display to another. The prism panel was one of ten panels salvaged from city streets and stored in the yard for possible future use. 2006 was the first year prisms have been displayed at the Open House. The photo below left shows a top view of the panel while the right photo reveals a much more colourful view from underneath as the light streams through the prisms.