GOOD GOVERNANCE
Managing subsidence, cracks & floor level defects Is underpinning necessary? So, you have some cracks emerging in your townhouse villa complex in the plasterboard walls, ceilings and cabinet works and/or your external walls (brickwork or painted render). Is this a sign of normal soil consolidation and settlement over time, or something more sinister like footing failure and structural damage?
Nature of floor level defects During construction it is almost impossible to achieve a completely level or flat floor slab, so the construction industry via its National Construction Code, Building Act(s) and regulations, and Australian Standards generally indulge “allowable tolerances”. What this means is that it is not unusual for floor levels inside townhouses or villas to be slightly out-of-level, but still within allowable tolerances. It may be that your finished floor slab was never entirely flat to begin with, so it is important to determine the nature of floor level variations before becoming alarmed or planning remedial works.
So, what contributes to floor levels changing? Building defect: The floor was not built level during construction, and not picked up as a defect so the rest of construction was constructed around the as-built floor level. In this instance you are unlikely to observe any functionality issues, cracks or other evidence of floor level defect. © stock.aadobe.com
Settlement or consolidation: The vast majority of new housing is constructed on imported fill, which is compacted to strict standards prior to construction. Over time this fill (soil) may consolidate further and ‘settle’,
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apparatus does not concentrate excessive water along the perimeter of the house where it could erode the soil around the footings.
Lynda Kypriadakis,
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Ensure your annual termite barrier inspections are being undertaken by the body corporate.
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Report any cracks to the body corporate that are wider than 10mm.
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Report any doors that foul or won’t open/close, or any glass panels that spontaneously break without any real cause.
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Ensure your caulking seal maintenance is up to date around the house.
Diverse FMX
causing minor deviations in floor levels and minor signs of non-structural cracking. Heave: This is where the soil foundation is reactive to water and swells/shrinks depending on how wet the weather is. When reactive soil types swell up with water in a heavy wet and rainy season, the swollen soil heaves up against the slab and may cause deviations in floor levels and minor signs of non-structural cracking. Footing failure: This is where the footings and/or slab were not designed sufficiently to deal with the soil condition. As time goes by the normal settlement and/or heave impacts of the soil adversely affects the structural integrity of the footings and slab because they may not have been designed properly to deal with the soil condition. Footing maintenance: As a lot owner or occupier you have a duty to maintain the veracity of your footings and foundation to ensure no adverse effect is caused on the structural integrity of the building, including: •
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Ensure there are no significant trees with root interference within the zone of influence of your footings. Ensure your drains are serviced regularly by a plumber to eliminate cracks, leaks or root damage. Ensure your irrigation
MANAGEMENT
Note: The CSIRO has put out a helpful document for lot owners and occupiers, which is available for purchase online, Foundation Maintenance & Footing Performance. This is a good guide to understanding and preventing soil-related building movement in housing.
Signs of floor level defects There are multiple signs that your floor levels may be outside allowable tolerances and defective, including: •
Cracks inside in your plasterboard walls, cornices, cabinets and ceilings.
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Dummy floor tiles or cracks in wall tiles.
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Cracks or gaps opening up in your external brickwork or rendered/ painted external walls.
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Doors fouling and not opening or closing properly.
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Broken window and/ or door glass.
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Broken pipes underground.
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The floor is noticeably out ResortNews | March 2022
