How Long Does It Take to Build a Prefab House?

When a prefab supplier promises a house "in 30 days", they almost always mean the assembly alone. Once you add the building permit, the foundation, services and interior finishing, a realistic figure for a single-storey prefab house of 100-150 m² in Turkey is about 3-6 months from permit application to move-in. Here is where that time actually goes, based on how these jobs run on site around Şile and Ağva.

Stage by stage

Design and building permit: 4-10 weeks

Legally, a prefab house is a building like any other. Under the Zoning Law (No. 3194) you need architectural, structural, electrical and mechanical drawings, a soil investigation report, a contract with a licensed building inspection firm, and a building permit from the municipality. None of this is faster for prefab. The permit takes as long as the municipality's workload and any requests for revisions dictate.

Before anything else, I ask for the zoning status document of the plot. Along the Black Sea coast many plots sit in village settlement areas, unplanned areas or agricultural land, and the rules differ for each. Some plots simply cannot get a residential permit. Close to the sea, the Coastal Law (No. 3621) applies: no houses can be built in the 100 m shore strip measured from the official coastline. If you are buying land, check this before you sign.

Soil survey and foundation: 1-3 weeks

A prefab house is light, but it still needs a proper foundation, usually a reinforced concrete raft. That means excavation, blinding concrete, waterproofing, rebar, the pour and curing. We normally specify C30 concrete with B420C rebar. I wait at least a week after the pour before assembly starts. By then the concrete has reached roughly two thirds of its 28-day strength, and it still needs to be kept wet and covered.

Clay soils and sloping plots are common inland from Şile. If the site needs a retaining wall or the excavation hits rock or water, this stage can stretch to 3-4 weeks. Near the streams around Ağva the water table can be high, which affects drainage and waterproofing details.

Factory production: 2-6 weeks, in parallel

This is where prefab genuinely saves time. Panels or steel members are made in the workshop while the foundation is being built on site. Sandwich panel systems can be ready in 2-3 weeks; a custom steel frame takes closer to 4-6.

The catch is that the design has to be frozen. Moving a window or widening a door after production starts means remaking finished parts. With masonry you knock a wall down and rebuild it. With prefab you lose weeks.

Assembly: 1-3 weeks

With the slab ready and materials on site, the frame and outer shell of a 100-150 m² single-storey house usually go up in 5-15 working days. Two-storey houses take longer because of the intermediate floor and stair opening.

Access matters more than people expect. Articulated trucks can't always reach plots on narrow village roads, so materials may have to be transferred to smaller vehicles, which adds a day or two. On days when the northeasterly poyraz wind is strong, lifting panels with a crane is not safe, and we don't.

Services and interior finishing: 4-8 weeks

Wiring, plumbing, wall linings, floors, kitchen and bathrooms take about as long in a prefab house as in a concrete one. This is where the speed advantage ends. The only thing that really shortens it is having tiles, fittings and kitchen units chosen and ordered in advance.

Exterior, landscaping and occupancy permit

Cladding, gutters, the driveway and garden take another 2-4 weeks. Then the building inspection firm files its reports and you apply for the occupancy permit (iskân). Permanent water and electricity contracts generally require it, so there can be a few weeks between "finished" and "moved in".

Total time by building system

System	Total time incl. permit (approx.)	Comment
Sandwich panel prefab	3-5 months	Fastest, least design freedom
Light gauge steel frame	4-6 months	Custom layouts, wide choice of finishes
Structural (heavy) steel frame	5-8 months	Large spans, larger villas
Reinforced concrete, for comparison	10-18 months	Depends on storeys and formwork/curing cycles

These figures assume a single-storey house of average size and a permit with no complications. A two-storey prefab house adds some time to assembly and finishing, while the permit stage stays about the same.

What usually causes delays

The most common delay I see on site isn't weather or supply. It's decisions. When window types, cladding colours or bathroom layouts are still being debated after work has started, each open question costs days.

The rest is more predictable. Municipal revision requests add weeks to the permit. Unexpected rock, fill or groundwater can double the foundation time. Winters on this coast are wet and windy from December to February, and concrete poured below about 5°C needs protection or has to wait. Steel and panel lead times also move with the market.

Use the permit period to finalise the interior. Starting production just before permit approval gains time, but you carry the risk if the municipality asks for changes. If you can, apply in spring so assembly and exterior work fall in summer.

Common questions

Can a prefab house really be finished in a month?

The shell, yes. A house you can legally live in, with finishing done and an occupancy permit, realistically takes three months or more.

Can you build in winter?

Yes. Assembly happens on dry, calm days, and once the shell is closed interior work carries on regardless of weather. The foundation pour is the part that needs care in cold weather.

Can I put the house up first and get the permit later?

No. An unpermitted building gets a stop-work order, a fine and possibly a demolition order. Being demountable doesn't change that.

A reliable timeline needs a site visit. If you have the title deed and zoning status document, we can tell you early on which stage is likely to run long. Details of our single-storey models are on the single-story prefab house page.