Estimating demolition is relatively simple. First, identify the scope of the demolition. Check all drawings, this includes the site, civil, mechanical, and electrical. Some general contractors only want the circuits to be “made safe,” and they will have their laborers perform the removals. Or, you will perform all the removals with your labor forces.
If you are making safe the circuits, then a detailed takeoff of the demolition is not necessary. Just estimate the number of hours that you think it will take to identify all circuits that need to be de-energized.
If the electrical contractor is required to removal all items, then quantifying the items marked for removal will be necessary. Once all items are counted, review the total hours in the estimate for the items. Then, adjust the total number of demolition hours in your bid summary or on your extension screen of your estimating software.
Things to remember:
- Add time for identifying and marking circuits that need to be maintained.
- Update panel schedules
- Dumpster costs
- Add additional time for getting materials removed from multi-story buildings or projects where access is limited.
- Depending on the scope of the demolition, a new temporary electrical service may be required.
- Be sure to protect items removed that will need to be reinstalled.
- Will a temporary Fire Alarm system be required during the construction period?
- Identify items to be returned to the owner and where the items are to be delivered.
- Include any disposal costs of contaminated materials.
- Be sure to include overtime for any required shutdown.
- Include any rigging or crane costs for heavy equipment being removed.
- In an industrial plant, you might have customer lock-out tag-out rules to follow.
If the total demolition hours are a large percentage of the total hours in the estimate, then take a closer look. If the hours are less than 5% of the total hours, then less scrutiny is required.
Remember, estimating is expensive, poor estimating is costly, and quality estimating is profitable.