The use of precast concrete panels as a cladding material can provide an economical and attractive method to enclose contemporary buildings. There are different forms for precast concrete structurally and its use is mostly in commercial and industrial projects.
Precast concrete wall panels may be supported on almost any kind of footing but mostly on pad footings at panel corners and strip footings. Slabs are usually poured between panels and sometimes assist support of panels. Ideally, precast wall panels should be joined at their edges or their top with fixings designed to absorb minor movements without distress but this is not always done.
Sometimes welded plates are applied that are fully rigid. Reinforced concrete shrinks for about a year after construction and footings move so there is every reason to expect movements between panels. Gaps between panels are usually filled with compressible material and should function as articulation joints provided the steelwork also permits movement.
Commercial and industrial buildings of this type usually have a steel roof frame that effectively ties the tops of panels together. They often have internal steel frames to provide bracing against lateral wind load. Structures of this type are usually well engineered and reliable.
Problems with precast concrete buildings.
- Incomplete sealing between foundation sections, leading to water entry
- Excessive spanning of areas by precast concrete foundation sections with no fill and no footing at all may lead to future water entry, floor slab settlement, or in severe cases, foundation movement
- Problems with precast concrete buildings are most often related to differential movement of wall panels and foundations and the way they are absorbed or articulated by the structure.
- Corrosion and deterioration of metal components, such as structural connections and metal wall framing
- Problems due to condensation forming within the wall construction. Condensation may form at the interior of the wall assembly due to inadequate protection against air flow through the wall, such as exfiltration of warm, moist indoor air, or by infiltration of cold outdoor air reaching the interior wall components.