Condominium facade inspection: finding loose tiles without scaffolding

The most dangerous exterior problem on a condominium is delamination and falling of tiles or mortar. The bond between concrete and tile weakens bit by bit through thermal movement and water ingress. The surface can look perfectly fine while a gap grows behind it — until one day a piece falls.

The basic way to find delamination is hammer sounding: tapping or rolling a test hammer across the wall and listening for the change in sound. It is reliable, but someone has to reach every part of the wall. On a tall condominium that means scaffolding, gondolas, rope access or aerial lifts.

Owner-occupied condominiums have another pain: the bill is paid by the owners’ association — the residents. When scaffolding goes up for major repairs, sounding can be done at the same time. But when the statutory ten-year mark does not line up with the repair cycle, scaffolding or gondolas must be arranged for sounding alone. That gap is the main reason infrared drones are attracting attention.

The drone carries an infrared camera to face the wall squarely at the right distance. A delaminated tile has an air layer behind it, so it heats faster than its surroundings in sunlight and cools faster as the wall cools. Infrared imaging captures that temperature difference. The advantage over shooting from the ground is a square-on view of every floor.

A condominium is a place where people live and pass by. Below are pavements and car parks; behind every window is someone’s home. Wind wraps around tall buildings and can gust up or swirl in close to the wall.

• Urban areas & people below: control access to pavements and car parks and route flights away from people. Tethered flight is an option. Urban areas & people below
• Height: upper floors are hard to see from the ground, for both radio and visual line of sight. Use observers and fly from where you will not lose sight. Height
• Wind & turbulence: wind accelerates at corners and roof edges. Keep an escape path away from the wall, and be ready to cancel on windy days. Wind & turbulence
• Residents’ privacy: windows and balconies will be in frame. Notify residents in advance, post the survey dates, and decide how images showing interiors will be handled (deleted or blurred).

An infrared image is a colour map of temperature. The hardest part is telling delamination from everything else: reflections in glass, the sky mirrored in glossy tiles, shadows from canopies, heat from air-conditioner units, changes in colour or material. Plenty of things cause temperature differences that are not delamination.

In Japan, Article 12 of the Building Standards Act sets up the periodic reporting system: owners or managers of designated buildings of certain uses and sizes have a qualified person, such as an architect, inspect them and report to the designated administrative agency. The interval is set by that agency, generally between six months and three years. Whether a condominium (apartment building) is covered depends on designation by the local agency, so check your own municipality’s rules first.

For facades, a 2008 revision of the relevant notice requires that tile, stone and mortar facades be checked by full-surface sounding or equivalent on the parts that could injure pedestrians if they fell, once more than ten years have passed since completion, facade renovation or the last full-surface sounding. Infrared surveys had already been used as an “equivalent” method, and a January 2022 notice revision made explicit that infrared surveys by drone (unmanned aircraft) with accuracy equal to or better than test-hammer sounding may be used. Around the same time MLIT issued guidelines on infrared facade surveys, including by drone, setting out capture conditions and procedures for confirming accuracy.

Flying is regulated separately. Condominiums are often in densely inhabited districts, and approaching a wall means flying within 30 m of people or property. Such specified flights need permission or approval depending on conditions. Tethered flights that meet set conditions can face lighter procedures, so check at the planning stage. Other places also mandate periodic facade inspection — Hong Kong, for example, has since 2012 required periodic inspection of private buildings aged 30 years or more (excluding domestic buildings of three storeys or fewer). Compare countries in world regulations.

If you are planning a renovation and want the survey steps in order, read how to survey a building by drone before renovation (Airffic World).

• Infrared in poor conditions: on overcast days, after rain, in strong wind or on faces without sun, delamination may produce no contrast at all. “Not visible” does not mean “not delaminated”.
• Behind balconies and canopies: walls hidden by railings and canopies, and walls inside balconies, often cannot be imaged from outside.
• Reflective materials: glass, metal and glossy tiles mirror the sky and surroundings and mislead the reading.
• The repair itself: finding delamination is not fixing it. Repairs still need people on scaffolds or gondolas.
• Judgement and accountability: the qualified inspector is responsible for the results in the periodic report.

What follows is the editors’ outlook. A notice on the owners’ association board reads: “Next week, on a sunny morning, a drone will survey the south face.” The images are laid on the same elevation drawings as last time, and only the areas where delamination has spread are highlighted. Residents can see for themselves which faces are likely to need work, and when.

There is no more rushing to put up scaffolding once a decade. Faces are checked a little every year, problem areas are known early, and repairs are folded into the long-term maintenance plan. Facade inspection shifts from a one-off survey for the law to a habit of watching over the health of the home.