Steel building kit or turnkey: assemble yourself, kit with assembly, or one contractor?

Three options, three scopes

The word kit means a calculated steel structure, fabricated in a workshop and delivered in bolt-together parts. What changes between options is who does the rest.

Contractors publish offers of this type: one announces turnkey from idea to handover ^[17], another from permit to delivery ^[22]. A Turkish maker announces four levels, from engineering only to full assembly by a certified crew, with kit only and kit with supervision in between ^[21].

Hallfort will sell the kit, with optional assembly by partner crews still to be selected. Foundations, slab, permit, architect, earthworks and electricity are not included unless the quote says so. Hallfort coordinates with your architect. For a single contract that covers everything, turn to a general contractor.

Who does what

In Belgium, a hall that needs a permit in principle needs an architect. The 1939 law requires an architect for works that need a building permit (article 4) and makes the profession incompatible with that of contractor (article 6) ^[10]. The company that sells and assembles the kit therefore cannot be the project's architect. The exemptions consulted cover small annexes: in Flanders a garage or carport of at most 40 m², or a prefabricated structure of at most 50 m², with height conditions ^[11], and in Wallonia a carport of at most 40 m² under conditions ^[12]. See permits by region.

Whatever the option, ask who fabricates the steel and require the fabricator's EN 1090 certificate and declaration of performance. Among Belgian contractors, Clarinval announces EN 1090 certification for execution classes 1 to 3 ^[26] and Meynen up to EXC3 ^[27]. The kit sellers' pages we read do not mention it ^[2][3][4]. That is not proof that it is missing, only an observation about those pages. See EN 1090 and CE marking.

Skills, tools and time for self-assembly

A kit is assembled without welding. One Dutch seller describes assembling a light frame with pop-rivet pliers and a drill ^[2]. Another announces a team of 2 to 3 people, no welding, and offers assembly training ^[4]. Dutch sellers supply drawings, calculations and phone support ^[2][3].

Lifting is the real issue for a large hall. For a German hall, a 30 to 50 t mobile crane rents for 8,000 to 18,000 EUR for 7 to 14 days ^[7]. On a small building a lighter machine may do: ask the seller for the weight of the heaviest parts.

These are sellers' announcements, not measurements. The permit time comes on top and depends on the municipality.

Price differences, with published figures

Assembly alone is priced at 89 EUR/m² for 450 m² in Germany (40,000 EUR excl. VAT, steel and cladding) ^[9], at 50 to 70 EUR/m² in a French consumer guide ^[13] and at 10 to 15% of the steelwork cost in the UK ^[14]. Adding 50 to 89 EUR/m² to a Dutch uninsulated kit of 146 to 225 gives an order of magnitude of about 196 to 314 EUR/m² assembled, crane extra (calc, to be verified).

A turnkey price is not comparable with a kit price: it buys more. Compare the scopes, not the prices per m². See the price per m² by type.

The risks of each option

• Kit to assemble yourself. The kit price contains no assembly, crane or foundation. One maker advises allowing 15 to 25% on top of the hall price for contingencies and options ^[7]. Labour and crane do not appear on the quote, but they exist.
• Kit with assembly. Check who provides the crane, who prepares access and who answers for a defect in the foundation. These points belong in the quote.
• Turnkey. The Belgian contractors we consulted publish no prices ^[26][27]. A global price is hard to compare line by line: ask for the breakdown.
• All options. Permit, architect and foundation remain necessary. A Dutch seller presents its models as permit-free subject to local rules ^[2]: check with your municipality before buying.
• Steel price. HRC rose about 24% in a year ^[23][24] and zinc 31% ^[25]. An indicative price can move before the binding price in the quote.

How to choose

• A kit to assemble yourself suits a simple building, without heavy insulation, with a contractor or crew able to lift and bolt, and with time.
• A kit with assembly suits you if you want to fix the price of structure and assembly without managing the crew. Foundations and permit stay your files.
• Turnkey suits a large insulated hall, a tight schedule or a client who wants a single contact for everything, foundation included.

For a first figure, use the configurator: it gives an indicative range excl. VAT. The binding price is in a quote, after a stability study for your site. See also foundations and the price index.