How to calculate construction cost

Whether you are preparing a competitive construction budget for a bidding project, or just trying to figure out the costs for the construction, remodeling or repair work you want to do, follow the steps below to ensure that Their work costs are accurate and their construction budgets are organized and complete.

Before you begin, review all the plans and specifications and consider whether you will need the services of suppliers or contractors to complete the task. If that is the case, give them the information they need to quote their construction or remodeling work as soon as possible. Usually, waiting until the last minute causes the quote to be inaccurate.

In order to ensure that you have sufficient time to receive and review the prices of your suppliers and subcontractors, set a delivery date for quotes, which must be at least one day before the tender expiration date. Ask suppliers and subcontractors to make their proposals in writing and in detail. If time does not allow it, take detailed notes of the tenders given over the phone.

If possible, obtain at least three estimates. The subcontractors’ estimates of work usually cover a considerable scale of prices and if you have three estimates for each job, you can make a better informed decision about the number you should use in your construction budgets. As the quote process progresses, make sure your subcontractors receive any changes or revisions you make.

Once you have the estimates in your possession, prepare a comparison sheet and list the major items that subcontractors will include. Often, contractors who present estimates of the same work include different elements in their proposals. Use the comparison sheet as a guide to review and collate the quotes you receive. Add money to a contractor’s proposal for something it has excluded and others have included.

Make a summary of estimates for all your costs and tenders. Divide all costs into three basic categories:

Construction materials costs include all materials, labor, equipment, etc., needed to build a building (eg foundations, windows, roof).

Costs not related to construction or remodeling, also referred to as general conditions costs or general direct costs, include all materials, equipment and costs directly attributable to the performance of the work but are not a real part of it (for example , Temporary sanitation services, waste containers, supervision costs, the cost of electricity for the project).

General overheads include other costs necessary to maintain your business, which are not directly attributable to the project (for example, rent, telephone, office electricity). Identify and quantify these costs and then increase your hourly labor rate to cover them or add a budget line to your construction budget for each project you are calculating.

General (non-production) costs can include 20 or 30 budget items, depending on the complexity of the project. Make a summary sheet and list the various costs and items you envisage. Many of these are directly related to the time it takes to complete each task, so you should have an idea of ​​the duration of the project. For example, if you estimate that you will need two temporary health services a week, you will need to know how many weeks to use them to determine the total cost.

Once you have the costs of building materials and the general conditions, determine the partial total. Your earnings, overhead, and insurance costs are usually calculated as a percentage of that total. Combine these costs with your partial total and you will get the full estimated cost.

Calculate the cost of work now

Before you start any quantity deduction of the drawings, read the specifications in writing. Often, the specifications manual includes special requirements or important differences and you must note them before continuing.

When you start reviewing plans to determine the amount of building materials and workers needed to do the work, these suggestions will help you stay organized:

  • First, check all the blueprints to get an idea of ​​what the job will require.
  • When making your detailed deductions, use felt-tip pens or colored pencils to mark the drawings. So you know when you have included something.
  • There are many ways to obtain the amounts you will need to prepare the estimates.
  • If you first calculate the quantities of all materials, it is easier to go back to allocate labor costs if you know the detail you were considering. Floor-level installation of a 2×4 lumber around a window opening requires much less work than one to 40 feet in the air under an eave.
  • The detailed description and the additional sheet make it easier for someone to review your work.
  • In the event of a revision of the plan, you can easily compare the new details with the previous ones and verify the impact of the change.
  • When the project is under construction, you will be able to more accurately compare the actual costs of materials and fieldwork. If in your estimate the work appears in a lump sum, it will be impossible to determine where it was calculated in less and where in more.

When calculating quantities, make sure you know the scale used in the drawings and the details. Check the scale with other flat sheets; sometimes the architect scores an incorrect scale on the plans. If you think you are seeing 1/4 inch drawings and are actually 3/16 inch, your quantities will be wrong and this will significantly influence your labor and materials costs.