Hull Paragon Interchange
Located in the centre of the historic market town of Hull, the Paragon Railway Station opened in 1847 and now provides regular rail and bus services locally and nationally. We were contracted to repair and sympathetically restore features of the G. T. Andrews-designed station entrance which was originally built in the Italianate style.
The project involved the removal of offending fixings and reinstatement of the structural integrity of the Listed building, as well as the replication of missing terracotta balusters and the dismantlement and rebuild of the portico parapet.
THE SCHEME OF REPAIR OF THE PILASTER BASES ENSURED MAXIMUM RETENTION OF HISTORIC FABRIC AND MINIMAL INTERVENTION.
Cill replacement – elevation I
Our first job at Hull Paragon Interchange was the replacement of the cill detail on two windows which had three main elements; the cill, a rusticated panel and a plinth course at low level. The replacement cill was composed of geologically matching limestone (Tadcaster). We carried out the work systematically, utilising mechanical aid for the larger sections and manual handling only for the smaller sections. A tiger 1000kg mobile lift table was used for the vertical and horizontal transfer of the cill(s) and rusticated panels.
The cill was carefully lowered onto a prepared bed of hydraulic lime mortar at either bearing end. Once in place and fully weighted, the table lift was lowered and removed. All mortar that squeezed out of the bed was removed and joints were finished accordingly. The rusticated panel below the cill course was then transferred and positioned using the same protocol and techniques. The smaller, lighter and more manageable moulded limestone plinth stone will be installed by hand by a team of masons together with the lower sandstone blocking plinth stone.
We introduced a code 5 lead flashing to the mid-level cornice, including a drip detail and flashing arrangement to the abutment with the main building. This provides protection to the cornice and historic stonework below. The drip detail will aid water circuitry and will allow rainwater to be discharged away from the building line, therefore helping to extend the lifespan of the building.
Pilaster Bases
Ferrous metal cramps and fixings were extensively used during the construction of the Hull Paragon Interchange Listed Building. Although the original intention of these fixings was to bond and connect adjoining pieces of stone together, they often forced them apart.
General weathering and water penetration attack the fixings, causing corrosion to occur and in turn expansion. As a consequence, rust jacking and delamination of the stone fabric take place, setting up a cycle of progressive deterioration and often structural displacement.
The effects of this were clearly visible on-site at the base of the pilasters where very substantial twice-turned cramps were utilised at the connection point. The physical damage was evident with some signs of movement apparent.
The scheme of repair involved the removal of the offending articles, ensuring maximum retention of historic fabric and minimal intervention. Temporary support was provided to the bearing sections of the pilaster before replacement bases, masoned to the original profile using geologically matching limestone sections were installed.
Terracotta Balusters & Portico Parapet
Following the careful removal of handrails, individual balusters and die blocks from the portico parapet, the base was prepared with a bed of lime mortar.
The base blocks were then re-fixed with new stainless steel cramps as required, ensuring a level base was created throughout ready for the actual balustrade parapet to be assembled.
The corner die blocks were then fixed in position using running lines to ensure verticality and alignment were maintained.
The balusters were then connected to the base using stainless steel dowels set in a thixotropic resin and the existing and new handrails were carefully transferred and placed on top. Again stainless steel dowels ensured a firm connection. Once the handrail was in place to the full length, stainless steel cramps were installed between each handrail joint as an additional precautionary measure. All remaining joints were pointed with lime mortar (NHL 5.0).
Testimonials
