COLA construction risks to avoid
What goes wrong with cheap COLA installs?
Cheap COLA installations typically leave out acoustics, natural light, heat management, bird control, and visual quality, because these elements are engineered out to reduce the upfront price. Including them upfront delivers a structure that students and staff actively use, which is where the value of the investment lives.
A common outcome of the basic-spec path is a shed-style build. Exposed trusses and hard surfaces carry sound reverberation through to bouncing balls and assembly speech, so acoustic treatment is worth specifying where teaching and assemblies happen underneath. Insulation addresses summer heat under metal roofing during the season when outdoor coverage matters most. Skylights or translucent roofing keep the space bright and reduce artificial lighting needs at midday. Closed truss designs reduce roosting locations for birds, which keeps health risks and cleaning costs in check. Aesthetic quality matters too: a well-designed structure becomes part of the campus identity and signals investment to prospective families visiting the school. Clearance height and orientation are structural decisions that are difficult to change once built, so specifying adequate height for volleyball or netball and an orientation that keeps afternoon sun out of players' eyes protects the space's programming options. Cost per usable hour is what determines return: a space specified correctly upfront delivers a better return across its lifespan.
When does a school COLA fail or underperform?
A school COLA performs best when the design is shaped by how the school plans to use the space, with the structure specified around that brief. Common elements that shape whether a COLA reaches its potential include full weatherproofing for scheduling certainty, acoustic treatment for assemblies, correct clearance heights for specific sports, and lighting specified upfront to enable community use.
Shade-only structures suit spaces where occasional rain disruption is acceptable; for timetabled use, full weatherproofing is the right fit. In a city like Sydney, rainy days fall across roughly a third of the school year, which is why timetabled spaces typically need full weatherproofing. Even fully waterproof COLAs benefit from acoustic planning (so teaching continues during rain) and correct orientation (so low afternoon sun doesn't heat the space from the west). Specifying adequate ceiling height for netball (minimum 8.3 metres) and adequate run-back zones around court edges keeps programming options open across the structure's entire lifespan. Community hire revenue, which can offset ongoing costs, requires artificial lighting for evening use and independent access so hirers do not need to enter school buildings. Both are straightforward to include at the design stage. Artificial turf underneath a COLA needs adequate shade and airflow from the roof to keep surface temperatures in check; without them, turf can run up to 20 degrees Celsius above outside temperature, which is a safety consideration. The consistent theme across performance is that when the structure is designed as a space, shaped by its intended use, the school gets a return on its investment.
What happens if COLA footing costs aren't quoted upfront?
When footing costs are excluded from a COLA quote, the approved budget doesn't reflect the final cost, and the remainder typically surfaces as a variation claim after the contract is signed and excavation begins. This is the single most common source of cost variation in school COLA projects, because ground conditions are unknown until the site is investigated, and site investigation is sometimes deferred to keep the initial quote competitive.
The mechanism works like this: the builder quotes the structure without specifying footing design or site investigation costs. The school presents that number to the board or grant body and receives approval. Once excavation begins and soil conditions are assessed, factors like rock, clay, a high water table, or unexpected underground utility lines can require footing redesign. A variation claim follows, and because the contract is already signed and construction is underway, the school's options at that point are limited. The variation can range from minor to substantial depending on how complex the ground conditions are. Ground-penetrating radar, which identifies underground conditions before quoting, is a standard risk-mitigation step. Greenline includes footing costs in every project budget after completing a site investigation, and our no-variation guarantee means the number presented to the board is the number the project is built for. Schools evaluating quotes from any builder should ask explicitly whether footings are included, whether a site investigation has been done, and what happens if ground conditions differ from assumptions.
What slows down a school COLA project?
The most common causes of delay in school COLA projects are council approval timelines, multi-party handoff gaps between separate architects, engineers, and builders, undefined project briefs, construction constraints on live school campuses, and variation claims triggered by unforeseen site conditions. Each of these can add weeks or months to the overall timeline.
Council approval is often the least predictable phase. A full Development Application typically takes 6 to 12 weeks, though delays are common when documentation is incomplete or when council requests additional information. A Complying Development Certificate offers a faster path at 5 to 15 business days, and not all COLA projects qualify. Traditional procurement, where an architect designs, a structural engineer certifies, and a separate builder constructs, introduces a handoff at every stage. Each handoff creates scope for miscommunication, gaps, and rework that extends the timeline. Construction on a live school campus is inherently slower than building on an open site, because deliveries must avoid drop-off, pick-up, and break times, construction zones need safety fencing, and heavy machinery use must be managed around student movement. Off-site fabrication reduces this impact by building steel components in a factory and delivering them ready to assemble, keeping the on-campus window as short as possible. Variation claims from excluded footings or unexpected underground services halt construction while the scope is re-agreed and re-priced. Schools can reduce delay risk by defining their brief clearly before engaging a builder, using an integrated design-and-construct provider, and scheduling major construction during school holiday windows.
