There are several design options that can be chosen during initial design process.
With modern non-traditional facades the link between appearance and form of construction is more flexible. For instance, stone may be placed using traditional methods or may comprise thinner slabs bolted to a carrier frame. Conversely metal panels may give a modern appearance to a traditional blockwork wall when they are used as overcladding.
It is common practice to think of design options in terms of materials, appearance and image, and indeed the client may well express preferences in terms of precedent buildings.
However, functionality, buildability, safety, time and cost also should be taken into account.
These latter aspects of the façade depend on the following primary decisions: Should the façade be a heavyweight or lightweight construction?
What areas of glass should be used and in what orientation?
Should the façade be prefabricated or site-assembled?
Should the façade be a bespoke design or a standard system?
What are appropriate combinations of primary structure and façade?
Although two building envelopes are seldom the same they are equally unlikely to be entirely bespoke. Most building envelopes are constructed from systems of components. These offer benefits over bespoke design but are unable to deliver a completely unique construction. Some of the benefits to consider are:
- Benefits of standard systems
- Cost
- Shorter design and manufacturing period
- Familiarity of construction
- Use of existing test results
- Appearance
- Greater structural capapabilities
- More advanced shading devices
- Benefits of standard systems
Standard system walls can be given a variety of styles by selecting appropriate infill panels and additional items such as brise soleil. It has to be remembered that even the most standard of systems will have bespoke components such as brackets, flashings, and interfaces with adjacent cladding. Modified standard systems are sometimes used. In these one or more of the framing profiles, such as a pressure cap, is changed but the structural and sealing components remain unchanged.
Bespoke systems comprise framing components that are bespoke to a project. The profiles are designed and dies cut to extrude the required cross-sections. Note that bespoke wall may also comprise standard systems components were appropriate.
This is the most common method of constructing curtain walls in the world. Similar techniques are used to assemble roof glazing.
Stick construction consists of a grillage of mullions supported from the floor slabs and transoms. These are assembled at site and the resulting openings are infilled with glazing or opaque panels.
It has the advantage that it is economical and the construction sequence is flexible. Disadvantages are the lengthy intallation time and high dependence on site workmanship to ensure acceptable quality.
Unitised construction consists of pre-fabricated units normally the width of a glazing bay and one or two storeys in height.
Units are supported from the edge of the floor slab. Units are delivered to site glazed and infilled and only the unit perimeter seals are made at site.
Unitised construction is marginally more expensive than stick construction but normally leads to a higher quality wall. It should be noted that the choice of materials has a greater effect on cost.
Unitised construction is quicker to install but requires better planning and larger lead times are required.
Rainscreen is a plane of panels designed to protect the wall from rain. It may be constructed as overcladding supported on a brick or block wall or as an integral wall supported from mullions or studs spanning from floor to floor.
Rainscreen overcladding is often used on refurbishment projects but may be used to advantage when constructing new buildings.
Integral rainscreen walls supported from framing members are dependent on an inner air barrier to carry wind load and give the required air permeability.
Structural glazing comprises frameless glazing in which each glazing unit is supported by point fixings, normally bolted connections.
The glazing units may be supported individually from a separate framed structure similar to that shown or a stick construction curtain wall. Walls of this type are frequently called 'Planar' walls although 'Planar' is a brand name and other products exist.
In true structural glazing the glass components transfer load. It may comprise glazing units suspended one from another or glazing units supported from glass fins or portals.
Structural sealant glazing is a method of bonding the glazing units to a frame. This has the advantage that the glazing appears from the outside to be frameless.
In practice the glazing is bonded to a carrier frame that is bolted to a framing system such as that for a stick construction curtain wall.
The glazing may be bonded on two edges (and framed on the other two) or it may be bonded on four edges. In the latter case small clips may be provided to provide mechanical retention.
Detailed design means tranformation of conceptual design to applicable system design with all the applicable design parameters such as dimensions, intersection n with other mateials and components.
Detailed design is considered by Novarte as a chain of processes from shop drawings to production drawings
It has to be noted that, even a plain wall of stick construction will have bespoke components that has to be designed. These include:
Bracketry
Perimeter interfaces
Penetrations through the envelope
Engineering design and verification
Most building envelopes are specified using a performance specification. This transfers certain design resonsibility to the specialist contractor.
The specialist contractor will exercise engineering judgements when interpreting a performance specification; in particular how performance requirements are to be met. There are many design solutions that may be used to meet a project specification.
It is Alcemero experience to select the components and materials to be used in the building envelope unless they are specified prescriptively.
Most of the time it is likely that Alcemero will select the glass type, operating hardware and so on, even the framing system to be used.
Shop drawings consists of the applicable details designed in coordination with system designs and indicates each single detail to form total system on site. These includes dimensions, jointing materials,insulating materials types, specifications etc.
Novarte is to be produced shop drawings and site drawings always deciding on joint locations, bracket design and other bespoke elements of the building envelope. It also includes details of additonal elements of the building envelope such as brise soleil.
Novarte design skills becomes very important in this particular case.
Production Dawings are required for the manufacturing of systems elements.
They are produced to transform shop drawings in a sort of production drawings.
Each single component of the system is drawn giving necessary dimensions and informations to be able to allow production department to manufacture system to suit the shop dawings.
These dawings are prepared using several ACAD and Solid Modelling Softwares used by competent Professionals employed by Alcemero.
