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Key Differences between a Contractor and an Engineer in the Construction Industry

Updated: Dec 24, 2023

Contractors & engineers' work typically complement each others. A work designed by an engineer can't get built without a contractor and often times a work done by a contractor can't be certified without an engineer.

Structural Concerns
Structural Concerns

A few weeks back, a post surfaced, inquiring about a recommendation for a structural engineer. Amidst the comments, one response stood out:

“Your best bet is to find a contractor with experience in structures because most structural engineers never touched a tool. They have great knowledge but that has to translate to your contractor. You want to be very careful that you’re not overpaying for knowledge that is not going to apply to your situation.”

I’m certain that this notion has crossed the minds of many, and some still hold this belief.

As an engineer myself, I respectfully disagree, and here’s my perspective showing key differences between a contractor and an engineer:

While it’s true that some engineers may not have hands-on construction experience, they excel at providing meticulous drawings that ensure work is executed correctly, adhering to building codes, engineering standards, and fundamental principles. This approach minimizes the need for corrections and prevents future issues, such as floor sags or compromised load-bearing walls.

Being in the field since 2005, I’ve collaborated with numerous contractors, both directly and indirectly. Most can handle standard tasks without detailed plans, relying on their experience. However, challenges arise when projects become customized and necessitate calculations or verifications.

Regrettably, I’ve witnessed many poorly executed reinforcements, where contractors or handymen selected beam sizes based on experience, resulting in incorrect support or undersized structures. Notably, homeowners often skip involving an engineer during the design phase before hiring a contractor, assuming they can obtain free advice from contractors who may provide estimates and initial consultations at no cost to secure their services. However, an engineer, when engaged, becomes your advocate, offering impartial guidance.

For the average homeowner, who lacks in-depth construction expertise, hiring an engineer proves beneficial when addressing structural issues. Most structural modifications require permits, backed by stamped drawings from licensed and registered engineers.

When clients reach out to me, I ask probing questions to understand their needs fully. This helps me assess whether I can genuinely add value during property inspections or site visits. If not, I guide them in an alternative direction.

Recently, I was tasked with evaluating a structural reinforcement meant to rectify a floor sag. Upon inspection, I was deeply concerned. The beam lacked sufficient support and had been haphazardly shored up with steel rods, as seen in the second and third images below. It was a subpar execution.

Moreover, the beam was improperly installed lower than it should have been, failing to brace the weakened, undersized, sagging beam. Shims were inserted to bridge the gap between the steel beam and wooden beam, as depicted in the first picture.

Additionally, note the slight warping or twisting of the beam in the second picture.

Furthermore, a steel post was added, but it was not tall enough. This forced the installer to use loose bricks to elevate its base, which rested directly on the concrete slab instead of a proper footer.

Unfortunately, I don’t have a picture of this improper support. Refer to my structural deficiencies (I) blog for an explanation of why this approach is flawed.

I strongly doubt that a licensed contractor oversaw this work, or at least, I hope not.

Typically, licensed contractors either collaborate with engineers or advise homeowners to engage one. I consistently stress to homeowners that hiring an engineer not only provides a layer of protection but also ensures that modifications meet engineering standards and building codes, reducing the likelihood of issues arising when the house is sold in the future.

Lastely, it is important to note that the home improvement consumer protection act 73 P.S. § 517.1 (HICPA) was adopted by Pennsylvania's General Assembly in October, 2008 and signed by the Governer as Act 132 of 2008. The law establishes a mandotary registration program for contractors who offer or perform home improvement in Pennsylvania. Reference the following link for frequently asked questions about the act:

Improper installation for a beam
Picture 1

Structural Engineering Deficiencies- 724-949-0004
Picture 2

Improper shimming not enough bearing
Picture 3: Improper shimming not enough bearing

Written by Firas Abdelahad, P.E.

Firas Abdelahad has been a practicing structural engineer since 2005, collaborating with a diverse range of professionals, including consultants, architects, investors, homeowners, contractors, and subcontractors. Together, they tackle the various challenges that can arise during the design and construction phases of projects.


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