Painting by numbers
15 Jan 2000
The preservation of plant and building fabrics - which, in practical terms, generally means painting - tends to be at the bottom of the list of priorities when project estimates are being compiled. Percentages of the main plant items (MPI) are normally applied without too much consideration being given by both the project engineer and estimator. Inevitably, this leads to the paintwork being underfunded, since it naturally is one of the last parts of a project to be started, at a time when funding may well have been diverted to other areas.
Irrespective of project specification, painting comprises two elements: materials and labour. Materials are the most variable and on inspection the cost can vary not only from area to area, but also on the discounts available from suppliers. In this case, we would recommend that material costs are taken from company records, as these will reflect the discounts for quantity and prompt payments, over which the engineer has no control, of course.
Here though we will concentrate on labour costs, and in particular labour factors. The use of labour factors makes it possible to apply local (to the installation) wage rates to the task in hand, whether it is a new project or a maintenance job. The total labour factor for a specific job is determined by adding factors descriptive of job conditions, as shown in the accompanying table.
In each category in the table, the base case is the zero-factor case. When compiling the total factor, multiply the total added factors by the base-case productivity of 9.3m2 per manhour to determine the total manhours for the job - except for special projects, details of which are available from the editor.
It should be remembered that every job will have portions of it that range from the very simple to extremely difficult to complete. Such portions of the job should be considered individually to get the best use of the these factors.
An additional point to note is that it has been found that when the painting is done with a roller, rather than a brush, net labour costs can be reduced by 15 per cent, but material costs should be increased by 7.5 per cent. A brush allowance should also be added to the net cost of materials by adding £0.02/m2 for all applications.
{{Labour factors for painting projects
Paint materials FactorOleoresinous, alkyds, phenolics 0Chlorinated hydrocarbon resin 0.10Chlorinated rubber, vinyls 0.30Neoprenes, epoxies, accelerators 0.60
ApplicationsOne coat application 0One coat spray 0.20One coat roller 0.30Each additional brush coat 0.40One coat brush + one coat spray 0.20
Surface conditionLoose surface removal 0Powdery rust or slight pinholes 0.30Rust patches 0.60
PretreatmentNo wash 0Wash 0.20Scrubbing 0.40Neutralising 0.20
Surface locationGround level 0Ground + 7-step ladder 0.5020-step ladder 1.00Extension ladders 1.50Scaffolding 2.00Bosons chair 3.00
Job interferenceNo interference 0External 0.10External remote from site cabins 0.20External contractor classes 0.40External disruption 0.60
EnvironmentClean conditions 0Moderate temperature/humidity 0.30Severe temperature/humidity 0.40
AccessStanding, painting at waste level 0Sitting, kneeling, stooping 0.30Reaching, crawling 0.60Lying, crawling, reaching 0.90}}
