COLA construction risks to avoid
What goes wrong with cheap COLA installs?
Cheap COLA installations typically omit acoustic treatment, natural lighting, heat management, bird control, and aesthetic quality, because these elements are engineered out to reduce the upfront price. Including them upfront produces a structure that students and staff actively use, which is where the return on investment lives.
What gets cut Basic-spec COLAs often ship with exposed trusses and hard surfaces that carry sound reverberation, which affects both assembly speech and bouncing-ball noise during sport. Skylights covering 5 to 10% of roof area and translucent roofing keep the space bright without extra artificial lighting at midday. Closed truss designs reduce roosting locations for birds, keeping health risks and cleaning costs in check. PVC structures include bird-proofing as standard.
Why spec matters long-term Summer heat under metal roofing is significant during the season when outdoor coverage matters most, and insulation or soffit lining addresses that. Clearance height and orientation are structural decisions difficult to change once built. Specifying adequate height for volleyball or netball and an orientation that keeps afternoon sun out of players' eyes protects programming options across the structure's lifespan.
Where aesthetic meets usability A well-designed structure becomes part of the campus identity and signals investment to prospective families visiting the school. Return on investment is best measured in cost per usable hour over the structure's lifespan, so specifying correctly upfront produces a better long-run result than value-engineering at the quote stage.
When does a school COLA fail or underperform?
A school COLA underperforms when the design is not shaped by how the school actually uses the space. The elements most likely to affect long-term use include weatherproofing for scheduling certainty, acoustic treatment for assemblies, correct sport-specific clearance heights, and lighting specified upfront to enable community hire.
Weatherproofing and scheduling Shade-only structures suit spaces where occasional rain disruption is acceptable; for timetabled use, full weatherproofing is the right fit. Sydney averages approximately 122 days of rain per year, according to the Bureau of Meteorology, which is why waterproof COLAs keep programming intact across the school year.
Clearance, orientation, and acoustics 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 lifespan. Correct orientation prevents low afternoon sun from heating the space from the west or putting glare in players' eyes. Acoustic planning matters for assemblies, because PVC absorbs more rain sound than metal.
Enabling community use Community hire can offset ongoing costs, but it requires artificial lighting for evening use and independent access so hirers do not need to enter school buildings. Both are straightforward to include at design stage. Artificial turf underneath a COLA needs adequate shade and airflow; without them, turf can run up to 20 degrees hotter than outside temperature, which is a safety consideration for students.
What happens if COLA footing costs aren't quoted upfront?
When footing costs are excluded from a COLA quote, the approved budget does not 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.
How the cost gap opens up The builder quotes the structure without specifying footing design or site investigation. 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 utilities can require footing redesign. A variation claim follows, and with the contract signed and construction already underway, options to renegotiate are limited.
Scale of the variation The size of a variation depends on how complex the ground conditions are. A minor subsurface change may add a small line item, while significant soil or utility issues can add tens of thousands or more. Ground-penetrating radar during site investigation identifies these conditions before quoting, so the builder prices the real footing requirement rather than a placeholder.
What to ask every builder When evaluating competing quotes, three questions expose the risk: are footings included in this number, has a site investigation been completed, and what happens contractually if ground conditions differ from assumptions? A design-and-construct arrangement with the budget locked after site investigation removes most of this variation risk.
See the Consult. Design. Construct. methodology
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 can add weeks or months to the overall timeline.
Approvals and procurement handoffs Council approval is often the least predictable phase, because documentation queries and requests for additional information extend processing time. 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.
On-campus construction constraints Construction on a live school campus is slower than on an open site. It requires managing delivery schedules around drop-off, pick-up, and break times, fencing off active work zones, and coordinating heavy machinery use with student movement patterns. Off-site fabrication reduces this impact by building steel components in a factory and delivering them ready to assemble, which keeps the on-campus window as short as possible. PVC membrane installation specifically takes approximately three days on site regardless of structure size.
Variation claims Variation claims from excluded footings or unexpected underground services can halt construction while 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.
