The performance and aesthetics of a building depend on good construction. CWCT testing is the most effective way to ensure your cladding is fit for the purpose to achieve a high-quality building envelope.
But determining water tightness is only one aspect of the importance of CWCT testing in facades. These independent standards give verification that glazing and cladding will achieve their expected values for your facade. Combined with good design and installation, CWCT testing gives you peace of mind that your building will perform as expected.
What is CWCT testing?
The Centre for Window and Cladding Technology (CWCT) has developed a robust framework for the weather tightness of a building envelope. The whole performance standard also covers wind resistance, impact resistance and airtightness.
CWCT testing checks that fabricators and installers have produced a robust envelope solution. At RGB Facades all our products, including our terracotta and brick cladding systems, have undergone independent CWCT testing to ensure performance and quality.
The building envelope standards apply to:
- Curtain walling
- Overhead glazing
- Walls with ventilated rainscreens
Types of CWCT testing
Testing for water tightness can take place in the laboratory or on-site. Extensive off-site mock-ups ensure that system elements achieve the performance levels required for the site exposure, height and scale of any building. Specific on-site testing checks early for standards of workmanship and at the end of construction for compliance with building regulations.
CWCT testing is designed to test the permanently sealed joints of a cladding system and includes:
Water is sprayed at a wall continuously for 15 minutes while an aircraft engine simulates wind force and direction. This test is designed to measure the amount of water that penetrates the rain screen. After spraying with water, the facade is dried, and all joints are fully sealed. Test probes will then take deflection readings at random to determine panel performance.
Hose and spray testing to 3 bar pressure are two on-site tests that check permanently sealed and open-jointed systems, respectively.
Suction and pressure testing
This test starts by using a fan to create a vacuum. The vacuum first simulates the panels being pushed back against the wall by an external force. Then it mimics the panels being sucked away from the wall. The pressure is increased incrementally until the safety factor is reached. This test determines whether additional sealing for airtightness is required.
This type of testing consists of repeated impacts from a steel ball and a 50kg leather bag full of glass beads. After each set, safety impact tests are carried out to ensure the integrity and performance of the cladding system.
The importance of CWCT testing
The building envelope determines much more than its aesthetics. It also impacts maintenance requirements and the energy efficiency of a structure.
According to ICE, the most common cause of facade failure is the inability to control water leaks. CWCT testing is a reassurance for your customers that their cladding product will deliver the expected performance levels.
High-quality CWCT tested systems are also designed to meet the following regulations, based on CWCT’s ‘Standard for systemised building envelopes’ specifications:
The National Building Specification (NBS)
The National House Building Council (NHBC) standards based on CWCT’s ‘Standard for systemised building envelopes’ specifications.
The RGB Facades process
At RGB Facades, we’ll always select the best materials for your project. That’s why our cladding systems are all independently verified using CWCT testing. Our facades are installed to the highest standards for your peace of mind, from high impact Dekton cladding to versatile and innovative aluminium cladding products.