Cost & risk

Why the cheapest prefab quotation is often not the cheapest project

Factory price is visible. Exclusions, transport and local work are less visible—and often decide the final cost.

A prefab price can describe several different things

One supplier may quote a structural shell at the factory gate. Another may include interior fit-out and export packing. A third may include ocean freight to a port but exclude destination handling and the final journey to site. Putting those numbers in one spreadsheet does not make them comparable.

Start every comparison with an Incoterm or delivery point, the drawing and specification revision, currency, tax treatment, quote validity and the exact building quantity. Then map the work packages that remain before the building can operate.

The cost stack buyers should compare

Low price can move responsibility to the buyer

A narrower scope is not automatically wrong. A buyer with a capable local team may prefer to procure foundations, utilities or installation separately. The danger is believing that excluded work has disappeared.

For each exclusion, identify the party that will design it, price it, coordinate the interface and accept the risk if it changes. “By others” is not a project plan. It is a placeholder that needs an owner.

Five ways the cheapest option becomes expensive

1. Freight efficiency was assumed, not calculated. A small change in packed dimensions or weight can alter container count, transport method or handling.
2. The route was checked too late. Road works, escorts, crane changes or remote-site access can add cost and delay after production is committed.
3. Local requirements cause redesign. A generic specification may need structural, fire, accessibility, energy or service changes for the destination.
4. The finish schedule is ambiguous. Buyers discover that visible fixtures, furniture, appliances or external connections were optional or excluded.
5. Interfaces have no owner. Factory and site contractors each assume the other will seal, connect, test or certify the same boundary.

Compare one delivered-project scenario

Create a common scenario for every option: same destination, quantity, room schedule, finish, route, foundation assumption, utilities, installation responsibility and target date. Keep uncertain items as ranges rather than forcing false precision.

Programme risk has a cost

Prefab can overlap factory production with site work, but that advantage depends on timely design freeze, approvals, foundations and logistics. If the factory finishes before the site or route is ready, storage, rehandling and financing costs can erase part of the benefit.

Ask each bidder for decision dates: when must layouts, finishes, openings and service interfaces be frozen? Which approvals are prerequisites to production? What information must the local team provide, and when?

Quality differences belong in the comparison

A scope matrix should capture performance as well as quantity. Compare structural design inputs, corrosion protection, insulation, windows, membranes, fire strategy, acoustic expectations, service components, testing, warranties and documentation. A lower-cost assembly may be appropriate for one use and unacceptable for another.

Red flags in a “turnkey” offer

• No named delivery point or Incoterm.
• No exclusions, responsibility matrix or interface schedule.
• No drawing revision or room-by-room finish schedule.
• No route, lifting or unloading assumptions.
• No explanation of local engineering and approval responsibility.
• No allowance for commissioning, defects and handover evidence.
• A single attractive total that cannot be reconciled to work packages.

The clearest option is often the safer option

Do not reward a quotation for hiding uncertainty. A transparent bidder may appear more expensive because it exposes work that every project still needs. Once all options are adjusted to a common delivered-project scope, the apparent price order can change—and so can the decision.