Unfortunately many schedules aren’t workable because some basic principles were forgotten. I have had clients want me to build the 2nd floor before the first – which as you can imagine in most cases isn’t feasible. Then there are facilities that are completed but can’t be operated because someone forgot to connect the utilities or services. We have probably all worked on projects in the rainy season, yet the schedule still expected us to be excavating and concreting foundations every day. Many schedules fail to take into account manufacturing lead times and some clients seem to think that contractors can receive a drawing and should be pouring concrete the next day – resources and materials are conveniently waiting on a shelf – immediately available and waiting to be called upon.
The one thing that’s worse than not having a construction schedule is having a schedule that is incorrect. Yet, many schedules aren’t correct. Here are a few common mistakes.
- The schedule isn’t resourced correctly or doesn’t take into account the available resources or that resources are required elsewhere on the project at the same time. It’s amazing how some schedulers don’t consider how you fit the required resources into the available space or whether the contractor or their subcontractor has the resources available. Have you really thought about those task durations and what’s required to do the work in the allocated time, or is it just an arbitrary (feel-good) number?
- The schedule doesn’t take cognisance of the client’s constraints such as drawing issue dates, restricted working hours and access to work areas. I have seen schedules with a start date that ignored when we would have site access or receive construction drawings. It pays to understand the contract and visit the work-site before preparing the schedule. We have often had to interrupt our work-flow while the owner’s processes took priority - this was usually in accordance with the contract document so we had no excuse or cause for a claim.
- The schedule doesn’t allow for mobilisation times – on some projects there is a lengthy process to get resources to the site and inducted onto the project. I have had projects where the client’s mobilisation process could take more than four weeks.
- Not taking into account the impact of the normal expected weather conditions. Wind, extreme heat, freezing temperatures and rain can all severely impact productivity and progress. Unfortunately sometimes projects are impacted by extreme weather events beyond what is normal, but schedules cannot be expected to allow additional time for these events which should form the basis of a claim for additional time.
- Allowing insufficient time for procurement and manufacturing lead times. Sometimes additional time needs to be allowed for design of these items, design approval, drawings and drawing approval.
- Failure to take account of the impact of adjacent structures on the schedule – these impacts include cutting off access or structures that must be completed first because they are deeper or impact the structure in other ways. It could also include how access scaffolding or cranes on one structure impacts the neighbouring structure. Service and utility trenches in particular can have a major impact particularly if they are deeper than structures, or pass underneath or need to be connected to the structure.
- Disregarding contractual completion dates. This seems obvious but is sometimes ignored.
- Not allowing time for commissioning.
- Not including all requirements to have an operational facility – which may include connections of utilities such as power, water, gas, etc
- Not allowing for inspections and testing. These tests could delay progress of the construction. In addition the facility may not be occupied or used if the test results aren’t available or various approvals haven’t been obtained.
What mistakes have you encountered on schedules?
Were you able to overcome these problems?
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