*Cladding Defects Flashcards
What common defects are found in curtain walling?
- Rarely ever watertight, therefore a mechanism for draining water is required for when wind driven rain gets through seals
- Fixings need to be accessible to regularly inspected
- Fixings need to be able to accommodate movement
- Sealants and gaskets fail for a number of reasons; adhesion failure (poor preparation), cohesive failure (poor joint design), delamination, reversion (turns back to a fluid)
What consideration must be given to stone cladding panels in their design?
Support! They need to be supported by gravity where lower panels bear the wight of the upper one, or they need to be individually fixed with appropriate mechanical restraint
What issue would you expect with marble cladding?
Thin marble sections can expand in any direction, which is very difficult to accommodate in design. The only available remedy is to remove and clad with a different material
What issue would you expect with limestone cladding?
Limestone is durable, but it is damaged by chemical reactions with the atmosphere. Sulphur deposits on the surface form a crust, which can fall
What defect is an issue with metal framed cladding systems?
Condensation can cause corrosion to the frame. To avoid this, the metal frame should be kept at a higher temperature (above the dew point) to the glazing, so that any condensation forms on the glass not the frame
What issues would you expect to find with low level pressure plates on cladding?
Low level pressure plates can be easily dislodged by a vandal. Repeated renewal of can lead to weakening of the fixings. It may be necessary to re-drill and re-secure a plate to give sufficient pressure
What issues would you expect with gaskets?
The lip of a gasket must exert pressure on the glass to remain firmly fixed in place. Gaskets are normally made of elastomeric materials (like butyl rubber) and they can degrade over time, including shrinking or becoming brittle
