What makes metal buildings different
On a conventional steel building, the engineer of record designs the frame and the fabricator prices the drawings. On a metal building system, the manufacturer designs the primary frames, secondary framing and bracing to the loads and geometry in the order, then ships a package with anchor rod plans, erection drawings and instructions. The builder or erector estimates everything around it.
So the estimator's job changes. You do not take off every member. You define the building precisely enough to get comparable package quotes, then estimate foundations, erection and every piece of scope the package leaves out. MBMA's Common Industry Practices (2024 edition) is the reference most manufacturers' terms are written around, and it is worth reading once end to end.
What the package includes, and what it does not
MBMA describes a typical sale as end and interior frames (columns, rafters, flange bracing); bracing, purlins, girts, eave members, endwall columns and base angles; bolts for steel-to-steel framing connections; and the exterior roof and wall panels with trim, fasteners, sealants and closures. Everything else depends on the order:
| Category | Typical status per MBMA |
|---|---|
| Primary and secondary framing, panels, trim, framing bolts | Generally included |
| Personnel doors, windows, framed openings, gutters and downspouts, insulation, roof curbs, canopies, mezzanine framing, crane runway beams | Accessories: included only when expressly specified in the order |
| Anchor rods, embeds, templates, leveling plates, rebar, concrete | Not commonly supplied by the manufacturer |
| Overhead and roll-up doors, stairs, ladders, rails, loose lintels | Not commonly supplied |
| Interior downspouts, drains, fire protection, MEP equipment, interior framing | Not commonly supplied |
| Flashing to tie into materials outside the system; AESS-grade material | Not commonly supplied |
Step 1: Define the building for every manufacturer
- Geometry: width, length, eave height, roof slope, bay spacing, frame type (clear span or modular with interior columns), endwall framing (expandable or not).
- Loads and code: building code edition, risk category, wind speed and exposure, ground snow, seismic parameters, and collateral loads for sprinklers, lights, ductwork and ceilings. MBMA expects the design loads, including collateral and auxiliary loads, to be specified in the order.
- Envelope: roof system (standing seam or through-fastened), panel profile and gauge, wall panels, liner panels, insulation system meeting the energy code.
- Openings and accessories: framed openings with sizes, personnel doors, windows, louvers, gutters, skylights, curbs.
- Special items: cranes, mezzanines, canopies, masonry wainscot or tilt-up walls, future expansion.
Send the identical definition to every manufacturer. Different assumptions on collateral load, roof system or insulation are the biggest source of non-comparable quotes.
Step 2: Level the package quotes
Lay quotes side by side and mark every line one includes and another does not: freight, engineering and stamped calculations, erection drawings, insulation, trims, gutters, framed openings, doors, curbs, and the warranty on the roof system. Ask whether the manufacturer is accredited under IAS AC472 if your spec or jurisdiction requires it, and confirm delivery lead time against the schedule.
Step 3: Foundations and slab
MBMA is explicit that the manufacturer is not responsible for foundation design. Foundations are designed by the project's engineer from the manufacturer's reactions, which you may not have at bid. Carry an assumption from a preliminary reaction sheet or a similar building, state it, and include hairpins or tie rods where frames need horizontal thrust resistance.
Take off the slab, perimeter grade beams or footings, column piers, anchor rods and any thrust ties. MBMA puts the cost of errors in the slab, foundation or anchor rod setting on the end customer, unless the builder built them, and makes the erector responsible for checking dimensions and rod locations before setting steel. Build that check into your erection hours.
Step 4: Erection
MBMA lists what the erector usually furnishes: labor, tools and equipment to unload and erect; a reasonable level of shimming; temporary guys and bracing (manufacturer bracing cannot be assumed adequate during erection); touch-up of primed steel; and cleanup. It also lists what erection usually does not include, such as receiving and inspecting materials, setting anchor rods, grouting under columns, field painting, cutting or flashing for other trades' equipment, and MEP or fireproofing work.
Erection is commonly estimated from your crew history by building area or package weight, split into frames and secondary, roof panels, wall panels, trim and accessories because productivity differs. Adjust for eave height, crane size and reach, site access, wind days and whether the slab is poured before erection. Note that MBMA's erection terms assume a normal 40-hour week; overtime and interruptions are extras unless your contract says otherwise.
Step 5: Close the scope gaps
- Anchor rods: supply, setting, survey and inspection.
- Receiving, unloading and checking the shipment against the bill of materials.
- Overhead doors and their operators, often bought separately from the framed openings.
- Insulation: in the package or by others, and who installs it.
- Gutters, downspouts, splash blocks and underground drain connections.
- Liner panels, interior partitions and lateral support of interior walls.
- MEP penetrations, curbs and supports for rooftop units.
- Permits, stamped drawings, special inspections and pretensioned bolt verification if required.
Where software helps
The package arrives as manufacturer drawings, but the rest of the job lives in the civil, architectural, structural and MEP sheets. RenderDraw's AI takeoff helps with the parts you measure yourself: slabs and foundations, openings and accessories from elevations, and site and MEP scope, each linked to its source sheet for review. Try it on a set with a free sample takeoff, check a budget with the metal building cost calculator, or see the PEMB takeoff guide.
