This project brings together almost every type of façade risk, and our design and construction solutions exemplifies what we do best.
Our façade replacement workpackage included:
- Demolition and disposal of existing plate glass and non-thermally broken framing members.
- Erection of capped stick curtain walling with high performance solar glazing.
- Installation of internal porch enclosure
- Installation of heavy duty commercial swing doors with stainless steel concealed panic bolts, bespoke full height 316 stainless steel handles, 316 stainless steel bollards.
- Frameless glazing over curved canopy.
This particular architectural façade replacement presented a number of challenges:
- The existing curved walkway bisects the new/existing screen; its construction creating the need for on-site templates of face glass and channels to suit it’s as built profile.
- The relationship of the screen to overhead precast panel and internal feature timber panel door restricting the solution to bespoke detailing.
- There was a significant discrepancy in existing opening levels generally.
- All opening widths varied as the opening was off square.
- The client had maintenance issues with aluminium doors in the past.
- Specific porch to stick curtain wall details needed to take recognisance of exiting structural features.
The interesting aspect of working as a specialist façade contractor is the use of architectural elements and layering. This research building sits alongside a university campus lake standing proudly in front of the 1960s precast concrete building behind.
The deep overhang of the metal clad soffit and the horizontal copper brise soleil are striking architectural features of this building, architectural elements contributing to the internal environmental strategy by managing solar gain and daylight penetration.
However, as fixed architectural fixtures they cannot be adjusted, hence on certain days depending on the external climatic conditions, they have a negative influence on occupant comfort. Passive solar gain and natural daylighting been supplemented by mechanical measures.
Counteracting mechanical measures by introducing a mix mode approach through natural ventilation, the opening casement top hung sashes within the curtain wall grid allow the occupant the ability to adjust the internal environment. An over-ride switch within each room affords the occupant to opportunity in managing internal comfort conditions.
This project was built as an extension to an existing building, some of its features are reflected in other buildings, new and old nearby.
The reason for talking about this building is simple; its roof forms the site for a replacement project.
Certain aspects of its design such as the curtain wall system, its ral colour, glass specification and brise soleil design are replicated in the replacement glazing hence maintaining visual continuity.
Refurbishment can be phased over longer periods, the important factor to consider in such instances is the ability of the designer to maintain visual continuity. From the outset the designer should correctly appraise for example system type, glazing specification etc. This was encountered here on two fronts.
- The soft coating of the solar control glass had been modified hence altering its light transmission (LT), solar factor (SF) and u-value. Glass samples in-situ was required to demonstrate visual continuity and performance compliance. Careful selection from recognised and established suppliers been the critical and crucial factor.
- Sightlines in framing members change from time to time as system companies modify profiles to improve performance.
- Ral finishes can vary depending on the paint powder, the paint applicator and the level of paint applied.
The choice of façade system is always important. Working at height and over an atrium rooflight can restrict the choice of façade assembly. On this project we choose we felt it more appropriate to use Stick Curtain walling. This was for a number of reasons.
- The screens can be fabricated in stick form, allowing easy assembly on site.
- The interfaces details can be designed to be more tolerant of building movement. An internal sleeve within the mullion chamber can be adjusted to suit the long term settlement of the structure. It can also facilitate additional live loading, building occupancy can fluctuate resulting in differential movement along the building slab edge. The primary vertical members can be set at a level to accommodate this movement without inducing compressive stresses from live loads.
- As the precast panel is not designed to carry the additional dead weight of the new glazing, the mullions extend to the floor behind the precast panel thus transferring all dead weight to the primary structure.
- This raised some interesting issues; the architectural section demonstrates the principal of transferring the dead weight to the base. In doing so one must take the time to open up the structure internally to ensure that the as built building matched the original construction drawings.