Providence Gas Company Purifier House

also known as Imperial Warehouse Company, Providence Teaming Company, City Tire Company

Once the center of an ambitious waterfront redevelopment project, the building is now underutilized

About this Property


The building most recently was known as Conley Wharf and owned by Patrick Conley. Portions of it were for rent, including a ground-level storefront that was home to Sin Desserts for years (now on Westminster Street).

Current Events

We are not sure what is currently going on in the former Purifier House. There seems to be a few small businesses located at this address, but our guess is that the space is largely underutilized.


This property is listed in the Guide to Providence Architecture, Providence Preservation Society. It was listed for the first time on the Ten Most Endangered List in 2022.

From the description of its inclusion into the Ten Most Endangered Properties, 2022

…The context affecting the fate of the Purifier House is largely location. Allens Avenue is a major artery running south from Downtown and serving as US 1A. The introduction of Interstate 95, parallel to the west, effectively severed Allens Avenue and the first block of several east-west streets from residential South Providence to the west. This sealed Allens Avenue’s fate as a location for largely noxious uses. Today, Allens Avenue is a lightning rod for citizens concerned with issues of environmental justice and the health and well-being of the riverfront and abutting neighborhoods — and neighbors!

The architectural and historical significance of the Purifier House is well-documented. Furthermore, this one building provides a snapshot of rapid, and sometimes ravaging, effects of industrial and environmental changes due to location and use. The preservation and future of the structure have less to do with integrity or adaptive reuse capacity and more to do with the harmful uses that surround it on the waterfront.

From the National Register Nomination Form, Edward Connors, 2007

Read the excerpted nomination


The Providence Gas Company Purifier House (1900) is a large, four-story, steel frame, reinforced concrete and brick industrial building with additions, located at Allens Avenue and Public Street on the Providence waterfront. It is a long, narrow building, oriented east-west, with an elliptical arched roof and a four-story stair tower in the center of its north elevation.

The building was used by the Providence Gas Company to purify the gas manufactured at the South Station until the plant was closed in 1917 and the rest of the buildings removed. In the 1920s, a new owner modified the interior spaces and exterior skin of the Purifier House so that it now resembles a more conventional industrial building. Successive owners made several additions — mostly along the south elevation — through the 1960s.

As built in 1900, the 41’ x 178’ Purifier House was twenty-one bays long and three bays wide. The first four bays on the western end of the building, comprising about 35’ of its total length, served as office space. This front area was divided into three stories, with the first floor about 20’ in height and the second floor about 14’ high. The third floor, which extended the length of the building, was about 10’. In the rear seventeen bays (about 140’) of the building, there was no intermediate floor level, creating a ground story 35’ high that housed the purification apparatus, multiple purifier “boxes” with each box likely occupying a bay.

The building’s most distinguishing characteristic was its steel frame, which was largely exposed on the interior, as much of it still is today. The frame’s principal members are twelve columns on the long sides and an intermediate pair at either end, each built up from riveted Z-bars and supported on a pyramidal brick base with a monolithic stone cap. Another interior pair of columns between the fourth and fifth bays helps carry the supports for the original second and third floors at the west end of the building; these supports are a pair of 38”-deep built-up plate girders that carry the floor beams.

Three pairs of longitudinal trusses provide lateral stability to the columns and help carry the transverse trusses that support the top floor and the roof. The lowest and middle pairs of these trusses, which resemble Pratt trusses, run only the length of the original purifier room; the top truss, which is a Warren truss, runs the full length of the building. The lowest truss is 48” deep; the middle truss 65” deep and the top truss is 32” deep. The longitudinal and transverse truss members are made up of angle irons with riveted connections; in the lowest longitudinal truss the vertical and horizontal members are laced.

The transverse trusses that support the top floor and the roof are spaced two to each of the column bays, so that half of them are supported by the columns and half by the longitudinal trusses. The trusses supporting the top floor are double-intersection Warren trusses, 65” deep. The roof is supported by bowstring trusses with a convex upper chord formed by a 10”-deep beam with angle lacing, except at the crown where there is a solid plate. The lower chord is made of two 1.5”-diameter steel rods connected by a center turnbuckle. The lower chord is pinned at its connecting points to the upper chord; these are the building’s only pinned connections.

The roof deck is approximately 6” of reinforced concrete. It was originally covered with a standing seam metal roof that has since been replaced with a rubber membrane. Visible from within the building are the outlines of 24” diameter holes located on the underside of the roof at the arch crown in thirteen of the building’s rear bays. These holes (now concrete-filled) mark the former location of a series of sheet metal roof vents corresponding to the purifier units for which the building was designed.

The original exterior surface of the building was stucco over wire lath. The original windows were wooden frame: 8 over 8 double hung on the ground floor; 12 over 12 double hung on the second floor; and 12-light single hung on the third floor. These corresponded to the bay configuration of the steel frame, with two windows between each pair of columns.

The stairtower was of identical construction to the main building except that it had a flank gable roof. Three bays wide, it had exterior loading doors at three levels.

In 1925, the building was reconfigured for warehouse use both inside and out. In the rear, three floors of reinforced concrete were constructed within the ground story formerly occupied by the purifying equipment. This created the present-day floor configuration: a roughly 11’-high ground story; a 9’-deep high second story; a 14’-high third story; and a fourth story (the original third floor) 10’ high to the lower chord of the roof trusses. On the ground floor the concrete framing consists of two rows of eight columns. Each row consists of four pairs of 18”-square columns, each pair supporting a 40”-deep heavy concrete beam. These beams carry the cast concrete floor joists and the floor slab. On the second floor, there are two rows of eight mushroom columns carrying the flat concrete floor slab. The columns are 15” square and flare to a 48”-square capital, with 3”-thick, 63”-square pad or drop immediately below the floor slab.

At the front of the building the1925 modification to four floors required the insertion of a new second floor in the c. 20’-high ground story. This floor is of slow-burning wood construction and is suspended by a series of steel rods from the steel girders that support the original second (now third) floor. This floor level is roughly 1.5’ lower than the rest of the second floor to allow for passage under the plate girders and is reached by a short flight of steps.

The original exterior skin and fenestration were completely removed and replaced by brick walls with large window openings filled with steel sash typical of industrial architecture of the period. The windows are grouped with three sashes to an opening. On the first, third and fourth floors the predominant window form is a 12-light window flanked by two 16-light windows with 8-light hoppers. On the second floor (with its lower ceiling), a central 9-light window is flanked by two 12-light windows with 6-light hoppers.

The stair tower was extended on the west end to accommodate a freight elevator, the gable roof was replaced by a higher flat roof and loading doors were eliminated.

The interior and exterior changes required some modification of the steel framing. The columns were completely encased in brick, except those in the stair tower and the two interior columns supporting the plate girders at the west end of the building. The bottom chord of the lowest longitudinal truss is now partially encased in the second floor slab and some parts of the bottom chord of the middle truss were cut to allow window operation.


The Providence Gas Company Purifier House (1899-1900) is a significant example of architectural engineering from the beginning of the era of steel construction. Designed and fabricated by a regional iron bridge maker that expanded into steel building construction in the early 1890s, the Purifier House represents an important category of early steel construction, the special-use manufacturing building, with the special use in this case being part of the coal gas manufacturing process. Of the handful of surviving Berlin Iron Bridge Company buildings in Rhode Island, it is the only Rhode Island example of the Company’s “arch truss” roof. Built for one of the earliest uses on the new Providence Harbor, and subsequently adapted for warehouse and light industrial uses, the Purifier House is also significant for its associations with the evolution of Providence’s industrial waterfront in the twentieth century.

Providence Gas Company

Providence was among a number of eastern seaboard cities and towns to establish a manufactured gas plant for municipal use in the mid-19th century. A series of discoveries from the late 16th through the 17th centuries led to the realization that the destructive distillation of coal yielded a high volume of hydrogen gas suitable for illumination. More than two centuries would pass before these discoveries would lead to practical applications in residential or factory use and for street lighting. Early 19th-century experiments in street and residential gas illumination took place in Newport, Rhode Island, as well as in Baltimore, Maryland.

The Providence Gas Company, chartered in 1847 and in full operation the following year, erected its first manufactured coal gas plant at the corner of Benefit and Pike Streets in Fox Point. A typical plant of this period (located near a rail or waterfront source of coal) comprised a retort house for distillation of the coal, washing and scrubbing apparatus for cooling and removal of tars, ammonia and other impurities, a purifier house for removal of hydrogen sulfide, a metering house for measurement of the volume of gas produced, and a holder or “gasometer” for storage. Providence Gas dismantled the Pike Street gas plant around 1870, at which time it built West Station on the west side of the Providence River at Globe and Eddy Streets. This plant comprised a retort house, condenser and scrubber building (with adjoining tar house), lime process purifier house, scrubber house, gasometer and office. This plant also included a second purifier house built in 1896. […]

Providence Gas Company built a second gas plant along the waterfront south of West Station in 1877. Called South Station, this plant was located in South Providence on the north side of Public Street on Allens Avenue Although more compact in its siting, the plant was similar in process and operation to its predecessor. The company substantially improved South Station in 1899-1900, rebuilding the retort house and purchasing land across Public Street to the south for a new iron oxide process Purifier House. The contract for the new building went to the Berlin Iron Bridge Company.

The Berlin Iron Bridge Company

One of a number of regional New England bridge fabricating companies, Berlin Iron Bridge Company began the fabrication of iron bridges in 1878. Success with iron roof and bridge trusses led the company to begin designing and erecting industrial steel frame buildings in the early 1890s. Within a few years, Berlin built Rhode Island’s first steel frame industrial building, a surviving machine shop for Fuller Iron Works (1893). Designed for industrial use, these buildings were notable for their special-purpose construction, rapidity of assembly, and strength. A December 1895 article in The Iron Age, a national trade journal of the iron and steel industry, discussed the growing popularity of steel-frame Berlin buildings in the Providence area.

The general design of these structures is the result of long experience and much study on the part of Berlin Iron Bridge Company to produce an economical building to meet the requirements of foundries and manufacturing establishments where buildings of considerable width are used, necessitating strength and plenty of light.

Although Providence Gas Company had worked with Berlin Iron Bridge Company before engaging them for construction of the Purifier House, this appears to be the first complete Berlin building contracted for either of their manufactured gas plants. An undated, ca 1895 promotional catalog describes and illustrates an iron roof designed for a Providence Gas “generator house”. By 1899, however, Berlin had erected a number of special-purpose, steel-frame buildings for industrial clients in the Providence metropolitan area including Pawtucket Gas Company and Narragansett Electric Lighting Company. […]

The construction of the Purifier House incorporated many of the characteristic features of early steel construction, such as the riveted connections and built up posts and beams composed of rolled bars with angle and Z-sections. The Z-bar column, composed of four Z-bars riveted to a central plate, was developed by the engineer Charles Louis Strobel in 1886. It was quickly adopted for building construction and favored for carrying heavy loads in the first two decades of steel construction. After Strobel designed a new wide-flanged beam in 1895, the Z-bar column was largely superseded by the H column and other rolled forms that were simpler to manufacture.

While taller than the other industrial buildings the Berlin Company erected in Providence, the Purifier House featured the same large volumes of high, open floor space largely unobstructed by intermediate structural supports. The extensive use of trusswork to stabilize the building’s skeletal frame reflects the Berlin Company’s origins in bridge building and their broad experience in the varieties of truss forms. This is most notable in the Purifier House roof structure. This use of the bowstring or tied-arch truss appears to have been unique among the Berlin buildings in Providence, which typically featured gable roofs supported by Warren or other triangular section trusses. The elegant curve of the “trussed arch,” as they called it, is reminiscent of the company’s trademark lenticular truss bridges.

Providence Gas Company continued to reconstruct its South Station plant, commencing further improvements in 1904 and 1908. By that time, however, the growing population of Providence and the continuing expansion of its industrial base were putting a serious strain on the production capacity of the West and South Station manufactured gas plants.

In April 1909 Providence Gas Company announced its intention to build a modern manufactured gas plant on a 40-acre parcel further south on the waterfront at Sassafras Point. This plant, which was designed for the consolidation of all gas manufacture at a single location, would have a 300,000 cu. ft/day capacity and utilize the Dessau Vertical Retort, a sophisticated technology imported from Germany and the first installation of its kind in the United States. The new works would also include a modern purification plant. Company President John W. Ellis stated in a Providence Journal article accompanying the announcement that the “water gas plant at Public and Allens Avenue will be operated as heretofore for an indefinite period. Eventually the manufacture of water gas will be carried on at Sassafras Point.”

Providence Gas Company decommissioned South Station in 1916, selling the parcels on both sides of Public Street shortly thereafter. The land north of Public was occupied briefly in the early 1920s by the Nitrogen Corporation. All of the buildings of the former gas plant except the 1900 Purifier House were demolished by the late 1930s. The former Purifier House and the land south of Public Street were sold in January 1917 to Mark Plainfield and Pearl S. Priest, the wife of prominent Cranston textile industrialist, Samuel Priest. […]

From the “Industrial Sites and Commercial Buildings Survey (ICBS)” by PPS and the AIA, 2001-2002, hosted by (now defunct)

It is a large, four-story, long, three-bay-wide, brick building set on the east side of Allens Avenue. The building is notable for its rounded roof and large, paired and tripled, rectangular, multi-light, fixed and awning sash windows which fill each bay. The first floor of the building’s façade has been covered in tile, probably dating to the 1920s or 1930s. A tall, four-story, flat-roof elevator shaft projects from the north elevation of the building. A one-story, concrete block ell with a single vehicular entrance projects from the eastern end of the north elevation. Signage on the building includes “Dunlop Tire Safety Specialists,” “BF Goodrich,” “Michelin,” and “City Tire Co.” Attached to its south side is a two-story, flat-roof ell with large, single-light, fixed sash on its first floor. This block was added sometime after 1937. Attached to the two-story ell is a one-story, flat-roof block with rows of vehicular entrances along its south elevation. According to the Sanborn maps, this block was constructed in 1969. At the east end of the four-story block is a large, one-story, flat-roof, brick ell which replaced an earlier wood-frame block shown on the 1918 map. This brick ell was constructed between 1918 and 1926.

A one-story, flat-roof, concrete block garage stands to the rear of the building on a separate lot.

This structure was built by the Providence Gas Company around 1915. The 1918 map identifies the structure as a Purifying House. The Imperial Warehouse Company occupied the building in the early 1920s. Historic maps note that the building was used for storage, shipping and receiving. By the late 1920s, Providence Teaming Company is identified as the building’s occupant. According to city directories, Providence Teaming was incorporated in 1921 and had offices on Dyer Street before locating to Allens Avenue. The company used the building as a site for their teaming and trucking company under its president John A. Woodward.

The building was left vacant in 1937. The City Tire Company began occupying the building around 1942. They utilized it as a site for the distribution of tires and are the current occupants of the building.

In the News

Conley Hopes S. Providence Project Will Be His Legacy

by Cathleen F. Crowley
Providence Journal | May 1, 2005

Patrick T. Conley tramps through the mud toward a 754-foot wharf jutting into Providence Harbor. Splotches of bird droppings bleach the wood planks. Cold air blows off the water, though Conley wears only a suit and tie. He strides toward a metal shack halfway down the dock and sits inside, protected from the wind.

“This is where we have coffee and we strategize,” Conley said.

Conley has big plans.

He envisions cruise ships and ferries pulling up to his wharf. He dreams of a 400-boat marina to the north of the pier and, on the water’s edge, a multistory hotel and condominium complex rising into the sky. He pictures a colony of artists selling their goods to tourists and sees the Sloop Providence and the Russian submarine tied to his dock. Visitors can shop, dine and enjoy the city’s maritime history here at “Providence Piers.”

Right now, though, it’s mostly mud and pavement.

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Conley has never built something this big. He’s developing a $35-million housing project in Smithfield and has completed a handful of $3-million apartment buildings, but the price tag for Providence Piers is closer to $300 million. He says he is talking with investors and potential partners, but no agreements have been made yet. No city boards have reviewed — never mind approved — the project.

But if anyone can pull it off, Conley believes he can.

Conley wants the waterfront development to be his legacy to Providence and South Providence, his hometown and boyhood neighborhood.

He is better known for buying properties at tax sales and selling them at a profit, a practice that has not endeared him to some people.

Is he hoping people will forget about his tax sale legacy?

No, he doesn’t mind if you remember that, too. That is Pat Conley, love him or hate him.

A framed 1918 map of Providence hangs on the wall of Conley’s temporary office on Allens Avenue. Conley points to the Burgess Cove neighborhood. His father was born there, he says. The cove was filled in and converted into a dump. Now it’s the Thurbers Avenue exit off Route 95.

Conley grew up at 80 Byfield St. by the train tracks, and he played on top of the gas tanks that dot Allens Avenue.

“This is the Conley family coming back to South Providence,” he said.

Conley, now 66 years old, has proposed building a hotel, condominiums, a marina and an 800-car parking garage on the land just south of the Fox Point Hurricane Barrier. Former Providence Mayor Vincent A. “Buddy” Cianci Jr. dubbed the area “Narragansett Landing” and targeted it for offices, apartments and marinas as part of his New Cities plan.

Conley’s property sits between Sprague Electric and ProMet Marine Services, where Public Street intersects Allens Avenue. He paid $2.3 million for nine acres that once housed the Providence Gas Co. He has already demolished three massive oil tanks and dismantled the pipes that carried the oil.

He also bought the City Tire building next door for $106,000 at a tax sale. The four-story, barrel-roofed building served as a warehouse in the 1910s when the wharf on ProMet’s property was known as State Pier No. 1. More than 18,000 immigrants disembarked at Pier No. 1 in 1915, making the city the fifth-largest immigrant landing, according to Conley’s historical research.

Conley has poured $3 million into rehabilitating the building, which he named Conley’s Wharf at State Pier No. 1. He has already leased the first three floors to an artists’ group, which will sublet the space for art studios under a five-year agreement.

He believes the artists will bring vitality to the area.

The Partnership for Creative Industrial Space plans to rent studio space to about 40 artists at a bargain rate of $6 a square foot, or about $500 a month per studio.

Lisa Carnavale, co-director of the partnership, is thrilled.

“If there are benefits that he can get from us, that is wonderful because we get benefits from him,” Carnavale said. “He gets a group of people that will bring life to an area that doesn’t quite have it yet. It’s going to bring an attraction. It’s going to kick-start some energy into the area.”

Conley wanted to devote the top floor of the building to a conference center where all the organizations that he is involved with could meet, but his wife and business partner, Gail, wanted a restaurant.

“She said the entire top floor for a conference center is even too big for your ego,” Conley said, with his wife at his side.

They compromised. The conference room will take the half that overlooks the water, and the restaurant will sit above Allens Avenue. Why doesn’t the restaurant get the water view?

Gail Conley rolled her eyes.

“I decided,” Pat Conley said.

“He will not change his mind,” Gail Conley said.

“This is what I call an enlightened despotism,” he added.

Conley is a lawyer, real estate investor, historian and author. He served as chief of staff to former Mayor Cianci in 1979. He taught history and constitutional law at Providence College. He earned a doctorate in history and a place in Who’s Who in America.

He also earned a reputation.

His critics, who include Dennis Langley of the Urban League, say he has contributed to blight in South Providence.

In 1979, Conley began buying up tax titles at municipal tax sales. He paid the delinquent taxes and property owners had a year to repay Conley or sell the property to avoid foreclosure.

Conley estimates that he has bought 8,000 tax titles in Providence. About 5,700 were redeemed by the property owners, and he took ownership of the remaining 2,300 when owners didn’t pay their debt, Conley said. Most of the properties were vacant lots or dilapidated buildings, he said.

“Only one owner-occupant was ever dislocated by me from a tax title problem,” he said. The owner refused to communicate with him, he said.

If the buildings had tenants, he said, he let them stay as long as they paid their rent.

Conley says his tax title purchases revitalized neighborhoods, because he cleared the tax liens, making them more attractive to buyers.

“The city itself was doing nothing other than holding them,” he said. “They were much better off in my hands, sitting there ready to be sold.”

But some didn’t sell for years and became neighborhood eyesores, said Langley, executive director of the Urban League of Rhode Island.

“The lots he has purchased are not cleaned up,” Langley said.

Langley acknowledged that the tax sale process is perfectly legal but added, “It is unconscionable for something of this nature to be legal.”

Carla DeStefano, executive director of SWAP (Stop Wasting Abandoned Property) has purchased more than 25 properties from Conley and converted them into affordable housing.

Throughout their negotiations, DeStefano said Conley has been fair.

“If you can blame Pat Conley for part of the problem, then you have to give Pat Conley part of the credit” for the progress in South Providence, DeStefano said.

Conley’s entourage of advisers follow him on a tour though the rehabilitated City Tire building. On his team, he has experts on restaurants, hotels, construction, real estate and history.

Conley charges ahead, speaking with the bullhorn voice of a football coach.

A thick wooden table is already bolted to the floor of his conference room. The table runs 30 feet 6 inches long.

“Six inches longer than Donald Trump’s,” Conley says.

The wide windows reveal spectacular views of the river, the city and the East Providence shoreline.

ProMet’s boatyard fills the view from the southern windows. About a dozen ferries and large fishing boats are propped up on stilts. The boatyard is gritty and magnificent.

“It creates ambiance,” Conley says.

Two newly installed fireplaces anchor the conference room and what will become the restaurant. One fireplace has 55 tons of stone and is the size of a zamboni.

Route 95 dominates the restaurant’s panorama. It’s beautiful, Conley says.

“At night, you have the white lights coming one way, the red lights going the other,” he says. “It’s a kaleidoscope of colors. And you can still see the boatyard.”

Add pink to the panoply of color: Cheaters strip club is right across the street.

Though he has not appeared before the city zoning board or the City Plan Commission, Conley has discussed his project with city officials, including City Planner Thomas E. Deller.

Conley’s proposal fits in with the city’s vision for the area, Deller said.

“The plan seems headed in the right direction,” Deller said. “We want people to be able to go out there and enjoy the water.”

Deller suggested that Conley build higher.

Conley had originally proposed a 130-room hotel on the waterfront. After he spoke with Deller, Conley’s architect redrew the development with a 320-unit hotel and a train line running along Allens Avenue. Deller wants the area to be dense enough to support a train trolley.

Meanwhile, Conley is busy recruiting attractions for the project.

He has convinced the nonprofit organization that operates the Sloop Providence, a replica of the Revolutionary War schooner dedicated to educational programs, to dock at his wharf.

He is also in discussions with the organization that operates as a museum the former Russian submarine now docked at nearby Collier Point.

Conley asked RIPTA officials to launch their Providence ferry to Newport from the wharf, which has a 27-foot draft at low tide.

Karen Mensel, a RIPTA spokeswoman, said RIPTA officials are interested in moving to Conley’s property. The wharf appeals to the transportation agency because it shortens the trip to Newport, has more parking, and bypasses the hurricane barrier, through which navigation is difficult.

The pilots “do it well, but it’s always dicey,” she said.

If Conley’s dock is suitable, Mensel said, the ferry could move there by the end of the year.

Conley’s next step is to build the parking garage on the land next to the City Tire building, but first he must clean up pollution at the former industrial site.

Then, he plans to build the hotel and marina.

Conley has owned many properties, but this one is different, he said.

“This is, by far, the one that is the most sacred to me,” he said.

He calls it his homecoming.