When planning for a construction project, you’re going to think about the typical things: Labor, materials like wood and roofing, equipment rental, and so on. But there are a lot of things you are likely to overlook that can make your costs go up significantly and that can increase the complexity of your project. For instance, have you thought about how many people you need to hire and what kind of timeline you need to set?

Here are a few of the many jobs and costs you might not think of that go into a construction project (and that you might need to plan for with your project):

Welding

Most construction projects involve a timber frame. However, steel and other metal reinforcements can strengthen the structure so that it lasts longer. Other buildings may require the metal reinforcements to support the weight of the structure or to support its functionality.

When metal reinforcements are required, welding will almost always be required. You can hire a traditional welder for some projects, but you may need something more heavy duty like a friction stir welding machine for larger projects or for those that require more precision. Your costs can be influenced by the choice you make, including how much you pay for labor and materials, or how much the timing affects the bottom line.

Materials Handling

Calculating the costs of raw materials isn’t as clear-cut as it may seem. Laborers can make mistakes with what they cut, what they install, and so on, and that can require you to have to order more materials and spend more money on your project. These simple mistakes can add up over time, and you can end up spending a lot more money than you had planned.

Major mistakes can add up to even more. Someone measured something wrong and you didn’t discover it until an entire wall was out of place. Or someone calculated the curve of an arch incorrectly, and now you have to rebuild it and cover the cost of all the replacement materials and the extra labor. You can end up spending thousands more on materials and handling if mistakes are not kept to a minimum.

Labor

Labor is one of the biggest costs in any construction project, and it can be just as difficult as materials to calculate because of all the variables associated with it. For example, people may call out sick or become injured, requiring you to cover their lost time and to pay someone else to fill in. Or you might have people out, which simply pushes the timeline longer, costing you more in labor.

People may work slower than you expected, they may make mistakes that they have to spend time correcting, or they may be delayed by things like rainstorms or heat waves. You should calculate some extra costs when you are planning your project, knowing that some of these issues will be inevitable. Just know that you may not be able to plan for everything.

Specialty Work

Electrical, plumbing, and HVAC work are all complicated and require the help of a specially trained technician. While these professionals can usually help you understand the proper scope and cost of a project, there are often unknowns that can cause your project to become delayed or to cost more.

For example, during a renovation, you might find that the electrical work has to be completely redone, rather than simply upgraded in parts like you thought. When the plumbing is being put in, you might find out that there is a rock bed that makes running the line harder, requiring a lot more tools and labor. Unfortunately, there’s not much you can do in these situations since having the work done properly is essential. Just make sure you get a thorough inspection and site study before you begin your project so you know what to expect.

The bigger a project is, the more unexpected variables you are likely to have. Just try to think through these and other scenarios that might cause your project costs to rise. The better the planning you do, the fewer unexpected costs you are likely to have. Make sure you account for the unexpected in your budget, just in case.