# Work resources that don't influence the duration of the task

I work on a construction project. I have a task that needs 1000h to be completed. Depending on the amount of manpower, the duration of the task will vary. To complete the task I need scaffolding that is rented and paid for by day rate.

How can I insert a scaffold resource (in my exercise it is a "work" resource) so it won't affect the duration of the task but still will show on the resource graph and cost report?

• Hi Mike, it's good practice to not write tags in title because Stack's tag system is good and we should trust it. See more here: meta.stackexchange.com/a/10648/364217 Jul 17, 2019 at 12:02

Project does not have a native way to handle a cost-per-day resource. One workaround is to use a custom cost field (at the task level) to calculate the number of days and multiply by a rate. Reports that show cost by task can be modified to show this custom cost field.

For example:

In this example, the resource "worker" has an hourly rate of \$50 and the "scaffold" resource has a rate of \$0. The tasks are set to Fixed Work so that increasing resources reduces the duration. The scaffold resource work on tasks 1 & 2 is set to only 1h so that it does not constrain the duration of the task. If it was set to 100h like the worker resource, you would have to manually keep the resource units in sync.

The `Cost1` field has this formula: `IIf(InStr([Resource Names],"scaffold")>0,500,0)*(DateDiff("d",Fix([Start]),fix([Finish]))+1)`. The first part checks to see if a scaffold resource is assigned, and if so, sets a daily rate of 500 (note this rate could be stored in a number field). The second part of the formula calculates the number of days, taking into account that if the task starts at noon on Monday and finishes at 9:00 AM on Tuesday, that it is 2 days.

The `Cost2` field has this formula: `[Cost]+[Cost1]` which simply aggregates the native costs for the tasks with the scaffold cost.