Field

What is fabrication in construction?

Fabrication is the cutting, bending, welding, and assembling of building components, usually in a shop, so they arrive at the site ready to install.

Two construction professionals review paper plans beside a tablet at a jobsite workbench.
Plan reviews connect field conditions, drawings, and the next decisions on a job. AI-generated illustration.

Fabrication is making parts. Structural steel is cut, drilled, and welded into beams and columns with connections. Sheet metal is formed into ductwork. Rebar is cut and bent to the bar schedule. Millwork is built and finished in a cabinet shop. Some work is fabricated in the field, but most trades prefer the shop, where the conditions, the tools, and the quality control are better.

Fabrication sits between design and installation, and it is usually where the schedule is decided. Nothing gets fabricated until the shop drawings are approved, and nothing gets installed until it is fabricated and shipped.

How fabrication fits a real job

  1. Detailing: the fabricator turns the design drawings into shop drawings with exact dimensions and connections.
  2. Submittal and approval: the shop drawings go through the GC to the architect and engineer. Comments may require resubmittal.
  3. Release to fabrication: once approved, the fabricator schedules the work in its shop.
  4. Fabrication and inspection: the parts are made, and on some work inspected in the shop.
  5. Shipping and delivery: sequenced to match the erection plan.
  6. Installation: in the field, where any fabrication error becomes a field problem.

Say a steel fabricator has a six-week shop slot for a $1.3 million package on a three-story office building. The approved shop drawings come back two weeks late because of an RFI about a column base plate. The fabricator loses its slot and slips another two weeks behind other jobs in its shop. A two-week design question just became a four-week delay to steel erection. This is why GCs track fabrication separately from delivery, and why late submittal reviews show up so often in delay claims.

Field fabrication still happens, and it has its own costs. Cutting and welding on site may need a hot work permit and a fire watch, and field labor is usually slower and more expensive than shop labor. When a fabricated piece arrives wrong and has to be modified in place, those costs are the real price of a detailing error, and someone will want to back-charge them.

Shop quality control also matters for warranty and inspection. Some specifications require shop inspections, certified welders, or mill certificates for the material, and missing paperwork can hold up acceptance even when the steel itself is fine.

Fabrication and billing

Fabricated components often get billed before they arrive on site, as stored materials. Many owners will pay for materials stored off site only with documentation such as an invoice, insurance, and a bill of sale or title transfer, and sometimes an inspection. Check the contract before you bill for steel sitting in the fabricator's yard.

Common mistakes

  1. Releasing fabrication before shop drawings are approved, then eating the rework when comments come back.
  2. Not field-verifying dimensions before detailing. See field verification.
  3. Treating the fabricator's quoted lead time as starting at PO, when it starts at approved drawings.
  4. No shop visit or progress check on critical packages until the ship date.
  5. Billing stored materials without the documents the owner requires.

Related terms

See submittal, long-lead items, lead time, mock-up, and bill of materials. For tracking packages from shop to site, read how to manage long-lead items.

Frequently asked questions

What is the difference between fabrication and installation?

Fabrication is making the component, usually in a shop. Installation (or erection, for steel) is putting it in place at the site.

Why does fabrication wait for shop drawing approval?

Because the shop drawings set the exact sizes and connections. Fabricating before approval risks making parts that do not match the final design.

Can I bill for fabricated materials before delivery?

Often yes, as stored materials, if the contract allows off-site stored materials and you provide the documentation the owner requires.

What is prefabrication?

Assembling larger pieces off site, such as plumbing racks, wall panels, or bathroom pods, to reduce field labor. It is fabrication at a larger scale.

Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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