Owners Corner

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	Mailing Address: PO Box 1187, Manly NSW 1655 AUSTRALIA Telephone: Tel: 02 9907 1688 Fax: 02 9939 5889 Mob: 0408 911 210

A summary written by Robert Speirs-Ferrari for owners faced with water penetration, floor slab corrosion and the messy inconvenience of rectifications.

Spalling concrete goes undetected causing concealed damage inside concrete slab floors occurring from water penetrating through the base of walls and sliding doors from faulty or deteriorated waterproofing flashings against balconies and terraces.

Another source of water occurs from overflowing laundry tubs, wash machines and leaking shower floors with defective membranes.

Slab floors with magnesite toppings were originally installed to make slab floors level and for acoustic reasons to reduce impact noise to the apartment below. Unfortunately, salt laden air, damp and water saturating through the magnesite, will migrate into the concrete slab floor causing a chemical reaction with the cement also high carbonation. This eventually creates severe corrosion of the embedded reinforcement steel cast originally within the concrete slab floor.

The first evidence of the owner noticing damage occurs when the floor surface of carpet, parquetry or ceramic floor tiling breaks and bulges upwards usually from a serious spalling concrete problem concealed below.

Rectification commences with extensive physical jack-hammering of the floor that often requires the occupants and their furniture to temporary relocate due to the extent of damage and the severe OH&S concerns with silica dust, noise and vibration. Vibrating echoed noise travels throughout the apartment building until the rectifications are completed.

It is often the case, severe corrosion travels through the floor slab of adjoining rooms and enters below into adjoining apartment ceilings. Additional rectifications occur for the safety and long-term structural stability of both apartments.

Whilst the work is being carried out, ceiling slabs require propping with adjustable jacks whilst the noisy, dusty and heavy jack-hammering excavations occur to the floor slab above.