Whilst the pre-finished steel and cladding system play a vital role in the appearance and performance of a given building, there are a number of components used in this type of construction that also need to be considered and specified correctly.
Here, an overview of the main components and their role and interaction with the building envelope is provided. This is intended to offer initial guidance and we recommend that the appropriate component manufacturers be consulted for more detailed specification information.
Buildings commonly use rooflights as a solution for industrial and commercial buildings, to comply with HSE workplace regulations regarding lighting. When pre-finished steel cladding is used, these generally consist of matching profiled translucent or transparent sheets.
Sealants are an important component in making a pre-finished steel clad building weather-tight. They are used whenever the pitch or laps of a roof sheet are inadequate to prevent ingress of water or snow through a lapped joint. They are also used to prevent the passage of moisture vapour from within the building through lapped joints, due to the influence of the vapour pressure differential.
Fasteners are mechanical devices used to secure cladding components to structures or other components. The result of the proper use of a fastener is known as a fixing. There are two classifications of fixing: primary and secondary.
Although only a small component, it is often the flashings which have the greatest impact on the overall appearance of a building. Paying close attention to detail in flashings can make a difference and deliver well executed building. Most weather tightness issues on modern, pre-finished steel-clad buildings are the result of poor flashings.
Rainwater goods, consisting of gutters, outlets and downpipes, work in the fundamental role of drainage. The design process and selection of correct materials can be complex, and it is recommended that a company specialising in the design and manufacture of roof drainage systems is consulted for more detailed guidance.
Buildings with a level of internal humidity which is higher than normal may require a vapour control layer. The purpose of this is to prevent moisture passing from the inside of the building into the roof construction. Unless this can be achieved, interstitial condensation will form in adverse climatic conditions.
The purpose of the membrane is to allow water vapour to permeate through from the insulation into the cavity above and yet prevent water from the cavity entering the quilt. Breather membranes are installed over the top of quilt insulation and below the external profiled sheet.
Filler blocks are a means of closing the profile cavities at junctions, where the blocks are inserted between the profile and the flashing. They are available for both the internal and external profile shape, and are cut to match the exact dimensions of the profile.
Insulative materials are used to give the required thermal properties to the building, and are available as part of a built-up system or within composite panels.