Access methodology for facade works: comparing rope access, scaffold and platforms

Access is frequently the largest single line item in a facade project, and on distributed repair scopes it can exceed the cost of the repairs. It is also the line on which quotations are least comparable, because contractors commonly select the method their business is equipped to deliver rather than the method the scope indicates.

The following sets out the cost structure of each method and the conditions under which each is appropriate.

Cost structure of scaffold

Scaffold pricing is dominated by fixed costs incurred irrespective of the quantity of repair work performed: erection and dismantling labour, hire duration, engineering design, protection screening, and in many cases council permits for footpath occupation.

The consequence is that cost per defect location rises sharply as defect density falls. On a survey, or on a scope comprising a limited number of dispersed repairs across a large elevation, the full cost of enclosing the building is incurred to access a small number of locations.

Cost structure of rope access

Rope access has a substantially lower mobilisation cost, comprising a certified team and their equipment. Productive time at the workface represents a higher proportion of the total cost, which is why rope access is usually the lower-cost method for inspection and distributed light repair scopes.

The saving is a function of defect density rather than of the method itself, and it reduces as the quantity of continuous work increases.

Conditions indicating scaffold

• Repair density. Where large continuous areas require substantial work, such as full render replacement, recladding or extensive concrete repair, technicians working from ropes cannot achieve the productivity of trades working from a platform. The fixed scaffold cost is amortised across sufficient work to justify it.
• Heavy materials and mechanical handling. Break-out of significant volumes, panel replacement and material handling require a working deck.
• Multi-trade programmes of extended duration. Where several trades require the same elevation over a period of months, scaffold is generally the lower total cost.
• Containment and public protection requirements. In some heritage and high-pedestrian-interface situations, containment obligations determine the method independently of the cost comparison.

Mast climbers and suspended platforms occupy the intermediate position, and are worth pricing on taller buildings with elevation-by-elevation scopes.

Establishing whether an access allowance is properly derived

The following questions establish whether the access component of a quotation can be assessed:

1. Is access itemised separately from the repair work? Where it is not, neither component can be compared between submissions.
2. Was defect density established before the access method was selected? An access method selected before the survey has been carried out is an assumption, and the cost of that assumption is carried in either direction.
3. Has a comparison been provided? The crossover point between methods differs on every building, and a contractor who has assessed it can present scaffold, rope access and elevated work platform options against the specific scope.
4. What certification applies? For rope access: IRATA-qualified technicians, documented supervision ratios, rescue plans and certified anchor points. A rope access price that does not carry these is not comparable to one that does.

Permanent anchor installation

A building fitted with engineered and certified anchor points reduces the access cost of every subsequent rope access activity, including condition surveys, sealant replacement campaigns, planned maintenance and make-safe attendance.

Where access is being engineered and paid for on a current project, the incremental cost of installing permanent certified anchors is generally modest relative to the cost of establishing access again on each future occasion. It is a decision worth assessing on a whole-of-life basis rather than against the current scope alone.

Costs and percentages are indicative. The crossover between access methods is specific to the geometry, defect density and programme of the individual building, and should be established by comparison against the actual scope.