Case 1
- Introduction
- Causes of Defects
- Good Practices
- Standards
- Maintenance and Diagnostics
- Remedial
- Similar Cases
- References
Maintenance and Diagnostics
Repair of spalled surfaces should be done by cutting loose and flaking material to the base and replacing
with new bricks or blocks or made with layers of mortar. Consolidate weathered masonry (to stabilise the degradation) in accordance with SS 509-2, BS 8221-2 or equivalent. Maintenance and repair of renders should be carried out in reference to BS EN 13914-1, ASTM C926-20 or equivalent. Attend to cracks on the façade surface promptly to control moisture ingress in order to avoid delamination. Re-tile deboned tiles or over-clad existing façade to remedy delamination (see also BCA’s guidelines for periodic structural inspection and periodic facade inspection of existing buildings).
Diagnostics of Defect (see also NDT)
Hammer Tapping Test
Tapping test may be used to detect hollowness, delamination, spalled or debonded plaster.by listening to the ‘void’ sound.
Fibrescope / Borescope
A fibrescope or a flexible borescope is a flexible optical inspection device that consists of fibre optic bundles with an eyepiece at one end and a lens at the other. A fibrescope usually comes in two bundles: (i) a fibre optic light bundle that is for illuminating the object to be investigated, and (ii) a fibre optic image bundle to relay the image to the eyepiece. It allows a direct visual inspection for an otherwise inaccessible part, as observations of remote, difficult-to-reach areas can be made through a video monitor with high-resolution images. The flexible fibres allow it to be manoevred in hard-to-reach or inaccessible areas.
It is often used to verify findings from other tests, such as infrared thermography or impact-echo testing.
Common applications include:
– Inspection of connecting condition behind the external cladding wall of a building.
– Inspection of defects on concrete surface(s) in a deep and narrow gap.
– Determination of corrosion condition of steel tendon(s) inside post-tensioning ducts of pre-stressed structural member(s).
– Investigation of service pipes, ducts and other inaccessible areas.
