When Do I Need a Structural Engineer for my project?

Are you unsure whether hiring a structural engineer is worth it?

If you’re starting a construction project, you’re likely scrutinizing every cost item in your budget. With average design fees adding up to a major chunk of costs, you may question the value of a structural engineer’s involvement in your project. To make an informed decision, get to know what services these professionals provide, and how they may apply to your project.

What do Structural Engineers do?

Structural engineers are professionals who design support systems for buildings and assess structural plans. They also have the authority to inspect buildings and advise architects, contractors, and owners on their projects’ structural design requirements. The title “Structural Engineer” is granted to Civil Engineers who earn it through their education and work experience.

A building’s structure is designed to interface with its architectural features, which is why structural engineers join the effort after the architectural drawings are ready. Architects plan the building’s appearance and use of space, then engineers design the supporting structure – foundations, columns, beams, slabs, and other load-bearing elements.

In California, most projects’ plans need a structural or civil engineer’s stamp to qualify for a building permit. Across the state, building officials have the final word in requiring an engineer’s stamp and deciding the scope of their involvement.

If you are planning a residential project, the California Business & Professions Code (CBPC) requires it to be designed by a Civil or Structural Engineer, if:

  • it’s a single-family home over 2 stories and a basement
  • it’s a multiple-dwelling complex with over 4 dwellings, over 2 stories, and a basement
  • it’s a complex with over 4 dwellings on one lot

Wood frame single-family homes lower than 2 stories and a basement may be designed by a non-licensed person, as long as they conform to the local adaptation of Division IV of Chapter 23 of the California Building Code. In theory, this means that you may hire an unlicensed designer to draft your drawings, or even try it yourself.

If your project is exempt from mandatory engineering approval, taking a DIY approach may seem like a cost-effective way to design your dream home. Before you do, consider this – your building official may send your plans back for a licensed engineer’s review after you apply for a permit.

There are plenty of reasons why building officials may do so. These include, but are not limited to, code compliance issues, seismic concerns, and the need for roof snow load calculations.

Code compliance

The CBPC requires your plans to conform to the building code, but other codes and statutes also regulate residential construction, for example:

  • The California Residential Code, a statute that dictates minimum room sizes in residential dwellings, which are not found in the CBC.
  • The California Plumbing Code, which regulates installation and inspections of plumbing systems.
  • Building Energy Efficiency Standards. Known simply as Title 24, this code covers building elements that affect energy use.
  • CALGreens – a statute that aims to reduce the negative environmental impact of buildings. It regulates planning, design, energy efficiency, water conservation, material and resource conservation and environmental quality.

Unless your design complies with all the codes and regulations listed above, the local Building Department must refer you to a licensed design professional.

Seismic concerns

While no part of California is safe from earthquakes, some areas suffer from notably strong ground motion. Regions close to active fault lines, such as the Los Angeles Metropolitan Area or the San Francisco Bay Area, may experience shaking strong enough to destroy even earthquake-resistant structures. If your home is located in such an area, getting your building plans stamped by a professional engineer becomes even more important.

Roof snow load calculations.

Most of California enjoys a Mediterranean climate and is spared the headaches of winter weather. However, some mountainous regions can get up to 210 inches of snowfall every year; if you’re building in these areas, your roof structure must be designed to resist snow loads. Building officials will want to see your roof load calculations and might ask you to get these done by a licensed engineer.

If you are tempted to avoid engineering design costs, remember: building departments tend to err on the side of caution, and your project may get delayed if plans are sent back for a licensed engineer’s review. To avert permitting delays, get a licensed engineer’s input on your project before you submit your application.

Is your project nonresidential? A licensed engineer or a registered architect must prepare your plans unless the work is limited to:

  • non-structural storefronts
  • interior alterations, additions, fixtures, furniture, cabinet work, equipment, appliances, and non-structural work needed to install them
  • non-structural building alterations need to install the above
  • agricultural and ranch buildings of conventional wood frame construction

The plans must conform to local adaptations of all relevant codes, and building officials may require a licensed engineer to review them.

Structural On-Site Evaluations

If your building shows signs of structural deterioration such as foundation cracks, you should have the damage professionally evaluated. Likewise, if you are planning to buy a building, it’s a good idea to confirm that it’s in good repair before you sign the check.

A licensed engineer’s structural on-site evaluation can put your mind at ease by assessing the condition of the building’s structural elements. The inspection typically comprises an assessment of the foundation, framing, shear walls, load-bearing walls, and the building’s envelope. Once the inspection is complete, you will get a report stating any issues and recommended next steps.

Structural Observations

Structural Observation is defined as “a visual observation of the structural system by a registered design professional for general conformance to the approved construction documents”. Structural observations are performed separately from building department inspections. They occur at the completion of a project’s milestones, once the structure is erected, and prior to finishes being placed.

In California, structural observations are required for projects that are:

  • assigned to Seismic Design Categories (SDC) D, E or F and Risk Category III or IV
  • assigned to SDC D, E or F and are 75’ or higher above the base
  • assigned to SDC E and Risk Category I or II and are two stories or higher
  • located where nominal design wind speed exceeds 110 and are classified in Risk Categories III or IV, or are higher than – 75’ above the base

Projects that are exempt from mandatory structural observations may be ordered to have one at the discretion of the local building department.

Design Everest Can Help

Whether you’re planning a ground-up construction project, remodel, or need a licensed engineer’s review for a part of your plans, our team is here to give you a hand. We can also offer you peace of mind by assessing your structure while it’s built and evaluating your existing building’s state of repair.

For more information about Design Everest’s full range of civil and structural engineering services and a FREE quote, call us at (877) 892-0288.

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