We have undertaken a number of substantial and extensive structural renovation, preservation and restoration projects which require experience in the evaluation and repair/modification of existing structures as well as additions to existing buildings.
Our restoration experiences range from primary structural elements (slabs, walls, and columns) to exterior building cladding (masonry, pre-cast, concrete and curtain walls.)
Restoration projects have included many different types of structures ranging from parking structures and churches to historic facades and high-rise office buildings.
Additional Heritage Projects:
- Macdonell-Williamson House, East Hawkesbury, Ontario
Quinn Dressel Associates was provided a great opportunity to contribute to the preservation of a piece of Canadian history by conducting the structural rehabilitation of the Macdonell-Williamson House. Constructed in 1817, the house was altered by its various owners who added certain features and demolished others. The two storey house consists of solid stone exterior walls and foundations, stone and brick chimneys and large timber beams spanning up to 13 meters in length.
During the time of the Williamson ownership of the house, the west fireplace, which was supporting the second floor and section of the roof was removed. Over time, this caused the second floor to sag resulting in diagonal shear cracks in the plaster wall. With the removal of the fireplace, the loads changed paths and traveled an alternative route down a partition wall and onto the ground floor joists. The weight of the roof and second floor placed a header beam supporting the ground floor joists under stress. As a result of the additional loading the beam rotated and deflected.
The Macdonell-Williamson House has a unique feature on the underside of its first floor timbers exposed in the basement - they have hand carved beaded edges. In order to preserve this heritage feature the Wood Epoxy Reinforcement (W.E.R.) system was used. The W.E.R. system is a method for inserting concealed reinforcement into the body of the existing wood to create a composite structural member of sufficient strength.
- Queen’s Park Complex – Hepburn, Ferguson and Macdonald Façade Repairs, Toronto
The Hepburn, Ferguson, Mowat, Hearst and Macdonald Buildings comprise the Provincial Government Building Complex located at Queen’s Park in Toronto, Ontario. The first four buildings are the four towers comprising the complex and are entirely clad in Queenston limestone. The Macdonald Block on the other hand is 2-storeys high and resembles a podium linking the four towers together at the base. It is clad in black polished granite. Constructed in the period from 1965 to 1969, the complex is highly regarded for its architectural and landscape design and considered a fine example of an institutional high-rise office building of the Modern Movement.
The Hepburn and Ferguson Blocks, are 11-storeys and 13-storeys high respectively.
Quinn Dressel Associates undertook the design of the restoration of the facades for the Hepburn and Ferguson Blocks. The Queenston limestone cladding of the Hepburn and Ferguson Buildings was deteriorating and was pointed with mortar containing lead. There was minor deterioration of the polished granite of the Macdonald Block as well as lead in the mortar pointing. The work on the Hepburn Building was executed from swing-stages including the lead abatement. This approach while reducing the disruption of construction activities on the complex presented challenges for the lead abatement which were successfully overcome. The dwindling supply of quality Queenston limestone challenged the team to affect repairs with minimal impact on the aesthetics and heritage character of the buildings.
- Stained Glass Panels – East Skylight, Queen’s Park, Toronto
It is assumed that the skylight dates to the building’s construction in the period from 1886 to 1893. It is the oldest of the three skylights in the Legislature. The three sections of wooden frameworks most likely were assembled elsewhere and set into place. The glass panes and the glazing bars were probably cut in situ once the basic framework was secured in place. This assumption is based on the absence of a systematic approach for joining the wooden stops and on the roughness of the glass cuts. A certain amount of glass has been replaced, presumably due to breakage. Additional support mechanisms have been attached and Plexiglas sheets were installed below the glass to protect passersby below from being showered with broken glass in the event of a mishap.
The skylight consists of three large oak frames lying horizontally in a box frame that is raised off the fourth storey floor. Two transverse yoked beams support the meeting joints. The perimeter of each skylight is constructed of solid oak with mortise and tenon joints at the corners. The perimeter of the opening is in effect the cornice, which carries the weight of the skylight down onto the columns below. Quinn Dressel Associates were contracted to investigate the skylight to determine the structural failures that needed to be addressed. The wood framing supporting the glass was cracked and the assembly of three layers of wood framing was coming apart. The integrity of the wood framing was therefore very suspect. It is impossible to affect a repair of the wood framing without destroying the character of the pieces so Quinn Dressel recommended that those portions of the wood framing that are irreparably damaged be replaced. The skylight could not be left in a position as-is without creating a risk to all those who would be pass below it. Quinn Dressel recommended that a temporary platform be placed below the skylight, which would be supported at the fourth floor level by a scaffolding system spanning across the fourth floor opening. The platform served four purposes:
* To provide protection from the hazards of any falling portions of the skylight.
* To afford access for a detailed survey to be carried out.
* To allow for access for disassembly.
* For replacement of the skylight.
Quinn Dressel Associated assisted in the undertaking of a detailed architectural survey of the skylight, which recorded details of the wood framing, glass panel patterns and colour, details of support; removal of the skylight and retention of the metal and glass portions of the skylight as well as those portions of the wood which were not cracked, broken or otherwise compromised. Architectural design and detailing of replacement wood sections of the framing was carried out as well as a re-design of the method support; replacement of those portions of the wood framing that was required and restoration of the remainder of the wood to achieve a uniform appearance and colour and re-erection of the refurbished skylight utilizing the platform and scaffold already in position.
- Toronto Old City Hall, Phases I-IV, Toronto
The historically significant building, constructed from 1891 to 1899, underwent extensive renovations under a repair program of four (4) phases. This major project required sensitivity, care and attention in finding solutions compatible with the original materials. The roof exterior was re-covered in copper, and repairs carried out on the roof trusses where required. Stabilisation of the dormer stonework gables was constructed. Replacement of deteriorated stonework was undertaken under the aegis of the architect. Quinn Dressel Associates was responsible for the repairs to the roof structure and the stabilisation of the dormer gables. The main challenges were the repairs of trusses spanning over 80 ft. and over 50 ft. high in places, in those areas where water damage due to water ingress had occurred. These areas were mainly at masonry wall supports and at roof valleys. Replacement of members often required detailed design of temporary works sometimes more complex than the final design of the permanent work. Ninety percent of construction under Phase I occurred at night. Quinn Dressel Associates has also undertaken the Justice of the Peace Office Suites project and the replacement of the gargoyles at Toronto Old City Hall. Our detailed knowledge of the structure of the building has been augmented accordingly.
Prior to refurbishment of a portion of the copper roof, a detailed condition survey was carried out of the roof trusses and masonry supports affected by the anticipated roofing replacement program, to ascertain the current condition with respect to deterioration and determine capability of safely supporting the loads imposed on them during the roof refurbishment construction and during their service life.
- Christ Church Cathedral, Montreal
Complete support of 128 year old Cathedral to allow for a five basement deep retail and parking development below, without any interruption of church activities or services.
It takes more than faith to lift a 17,000 ton 128 year old church off its foundations, and excavate 15m of earth from under it, and to continue services as usual. The church was within a new multi-level shopping centre taking place around and under the old Christ Church Cathedral in Montreal. Plans included two new retail levels and one parking level to be constructed right under the Cathedral.
The Gothic church was originally built in 1860 and was one of the few churches in Canada built completely by stone. The spire became a problem over the years, because the structure was built on subsoil, and it began settling even before completion. By 1927, the steeple was leaning two feet from the vertical and causing cracks in the rest of the church. The top half of the stone steeples was removed and rebuilt with metal and cast aluminium panels that look like stone. The cathedral is 200 ft. long and 109 ft. at its widest point, with the steeple rising 17 storeys above ground level. The structure weighs 6000 tons and the steeple 1500 tons.
Engineering ingenuity allowed the final phase of the Maison des Cooperants project in mid-town Montreal to get underway, although it looked as if divine intervention was at work when Christ Church Cathedral was suspended to permit construction of the underground shopping/parking levels for the development. The “cathedral-on-stilts” caught the attention of all passers-by in Montreal. Suspending the church was an engineering feat never before attempted.
The citation in winning the Association of Consulting Engineers of Canada’s Award of Merit read: “The challenge faced by Quinn Dressel Associates was putting the church on new foundations without interrupting services during the construction period. The delicate and possibly strained condition of the building required an approach that would not allow any appreciable movement during or after the implementation stage…(it was executed) successfully with movements never exceeding 3/16 inch…”
Key to the success of the underground shopping mall which was part of “Cathedral Place” high-rise office development in the heart of downtown Montreal was the feasibility of building a two storey shopping mall and one level of parking under Christ Church Cathedral.
The church foundations, which had a history of settlement, were masonry spread footings supported on a layer of clay with glacial till and bedrock about 45 feet to 50 feet below grade. Completing the support of a 128 years old Cathedral to allow for a five basement deep retail and parking development below without interrupting services during the construction period was a considerable challenge.
The technical challenge was to minimize building movements during or after the implementation stage. The solution was a post-tensioned system which balanced the church loading and prevented any vertical movements of the already strained building. The wooden floor was left in place and all work was confined to the basement area, thus ensuring continuation of religious services throughout construction.
Caissons, socketed into bedrock at a depth of 18m, were installed outside the church. Concrete beams, 1.8m deep, designed to carry the building in section – were threaded through the existing foundations. A secondary system of 1.2m deep girders was designed to enclose all masonry foundation elements and transfer the load to the main concrete beams. The soil was then excavated from under the building to leave it dramatically perched on “stilts”.
Award: 1988 – Canadian Consulting Engineering Award – Award of Merit for The Design of Christ Church Cathedral Underpinning
- St. Michael’s Cathedral, Toronto
Built in 1848, the Cathedral structure consists of load-bearing masonry supporting a wooden ground floor and wood truss roofs over the nave and side aisles. The spire was added in 1868. The floor of the nave and side aisles were modified by the introduction of steel beams, which a 1995 report by Larkin implies was carried out circa 1938, and some additional masonry supports were also added at that time.
For the St. Michael’s Cathedral project, we identified distressed masonry elements such as pinnacles, and provided designs for their stabilization. We designed the underpinning of the foundations for the creation of increased headroom within the crypt. The jacking and underpinning of the interior columns of the church were carried out without deformation or deflection of the existing building elements. We provided the structure of the new elevator and the new replacement of the balcony choir loft. We also designed and upgraded many structural elements within the building.
Award: 2017 – Ontario Steel Design Awards – Award of Merit for Projects Converted Or Innovated Using Steel
- County of Lennox and Addington Information Service Museum, Napanee
Detailed Condition Survey including repair cost estimates of the predominantly limestone two-storey structure. This heritage building was originally constructed circa 1864 of masonry brick, steel, wood and concrete combined with limestone walls.
- Toronto Gospel Lighthouse, Toronto
Nave Wall Repairs - the scope of work included repairs of existing deteriorated timber columns by complete removal and replacement of brick cladding and columns.
The Toronto Gospel Lighthouse was built in two parts, circa 1906 and 1923. The main structure consisted of tied wooden roof trusses at 12' 3" spacing, spanning approximately 40', supported by 5" by 6" raking wood posts, supporting a king post truss. The posts appeared to have been tied together with 2/2" by 10" wood beams, at ground floor extending the full width of the building. The overall structure was clad with non-load bearing brick. The roof consisted of wood purlins supporting wood planking and felt tiles.
A Physical Risk Assessment carried out by Quinn Dressel Associates revealed the roof trusses had failed and were deflecting to such an extent that the overall structure was in a state of unstable equilibrium and required immediate remedial attention.
- Stained Glass Panels – East Skylight, Queen’s Park, Toronto
Quinn Dressel Associates assisted in the undertaking of a detailed architectural survey of the skylight, which recorded details of the wood framing, glass panel patterns and colour, details of support; removal of the skylight and retention of the metal and glass portions of the skylight as well as those portions of the wood which were not cracked, broken or otherwise compromised.