“Turnkey shell” in residential construction: technologies

What is a “turnkey shell” in residential construction

In residential construction, a “turnkey shell” usually means a completed load-bearing envelope of the building, ready for subsequent works: MEP systems, façades and interior finishes. For a developer or private builder, this is a way to fix a clear scope of work and timeline: from substructure to the finished structural frame of the house.

In its basic configuration, the “shell” includes:

• foundation (strip, raft/slab or pile-raft — as per structural design);
• load-bearing frame (cast-in-place, precast RC or modular-concrete);
• external walls and inter-apartment partitions as per design;
• floor slabs and stair-lift cores;
• roof preparation (roof slabs, parapets, embedded parts for MEP systems and, if required, for solar/PV);
• main embedded parts and openings for engineering utilities.

All solutions are selected according to the ToR and working documentation: these are what determine the technology, schedule and budget.

Three basic technologies: cast-in-place, precast RC, ready-made concrete solutions

In Tashkent and the regions of Uzbekistan, three approaches are most often used to form the shell of residential projects:

1. Cast-in-place reinforced concrete frame with cast-in-place or precast infill.
2. Precast reinforced concrete structures (RC) — panels, slabs, stair flights, blocks.
3. Ready-made concrete solutions — modular and block systems, where large elements with maximum factory readiness are delivered to the site and installed by crane.

Each technology affects the schedule, cost and site organization in its own way.

Cast-in-place frame: when it is beneficial and how it affects the schedule

Features of cast-in-place

Cast-in-place technology involves installing formwork, reinforcement and concreting directly on site. This provides high flexibility of layouts and the ability to adapt the design to the plot and architecture.

Key features:

• flexible column grid and possibility of large spans;
• convenient for complex façade and terrace architecture;
• minimal number of assembly joints;
• possibility to combine with steel structures (canopies, balconies, stairs, railings).

Impact on schedule

The schedule for cast-in-place depends on:

• volume of concrete and number of storeys;
• selected formwork system (proprietary, movable, large-panel);
• logistics of concrete and reinforcement;
• work organization (number of shifts, availability of tower/mobile cranes).

Cast-in-place requires more time for each cycle (reinforcement, formwork installation, concreting, strength gain), but allows continuous work without waiting for deliveries of large precast RC elements.

When cast-in-place is justified

• large-scale developments with several phases and repetitive sections;
• projects with underground parking, podiums, complex geometry;
• high-rise buildings where spatial rigidity of the frame is important;
• plots with complex configuration where standard panels do not fit.

According to the ToR, a cast-in-place frame can be combined with:

• precast stair flights and landings;
• precast floor slabs;
• steel trusses and columns in the podium part.

Precast RC: panel and large-size elements

What is considered precast RC in the context of the “shell”

Precast reinforced concrete structures are factory-made elements delivered to the site ready for installation:

• wall panels (external and internal);
• hollow-core and solid floor slabs;
• stair flights and landings;
• balcony slabs, parapet elements;
• foundation blocks and beams.

Advantages of precast RC

• high installation speed with well-organized logistics;
• factory quality of concrete and reinforcement;
• predictable geometry of elements;
• reduction of “wet” processes on site.

For Tashkent and the region this is especially relevant for projects with good access for heavy machinery and the possibility to use mobile cranes.

Limitations and requirements

• need for precise design adaptation to the plant’s RC product range;
• strict requirements for installation accuracy and joints;
• dependence on the plant’s delivery schedule.

This technology is reasonable to consider when, according to the ToR:

• there is repetition of sections and typical floors;
• fast commissioning of construction phases is important;
• the site allows for storage of elements and crane operation.

Ready-made concrete solutions: modular and block approach

Essence of modular concrete solutions

Ready-made concrete solutions are enlarged modules that combine several functions at once: load-bearing walls, floor slab, and sometimes even part of the MEP chases. Installation resembles assembling a construction set from large blocks.

Examples:

• block sections of bathrooms and shafts inserted into a cast-in-place or precast frame;
• large modules of apartments or rooms with high factory readiness.

Where the modular approach is effective

• projects with a high level of standardization (dormitories, aparthotels, standard apartment layouts);
• projects where commissioning deadlines are critical (rental housing, income-generating residential buildings);
• complex inner-city sites where it is important to reduce the number of operations on site.

Requirements for ToR and design

Modular solutions require:

• early technology selection at the concept stage;
• precise BIM or 3D design of joints and MEP penetrations;
• strict tolerances for foundation geometry and installation areas.

In return, the client gets predictable timelines and minimization of “wet” processes on site.

Technology comparison: speed, flexibility, site requirements

Key comparison parameters

1. Construction speed

   • Cast-in-place: stable pace with good organization, but tied to concreting cycles and strength gain.
   • Precast RC: high installation speed with timely deliveries and a prepared site.
   • Modular solutions: maximum on-site speed, but more preparation at the design stage.

2. Layout flexibility

   • Cast-in-place: maximum freedom to change column grid and partitions.
   • RC: limited by panel and slab sizes.
   • Modules: high repeatability; changes after production launch significantly increase costs.

3. Site and logistics requirements

   • Cast-in-place: concrete and reinforcement logistics are critical, but storage area requirements are lower.
   • RC: requires access roads, storage areas and crane operation zones.
   • Modules: higher requirements for lifting equipment and survey accuracy.

4. Schedule risks

   • Cast-in-place: dependent on weather conditions and work organization.
   • RC and modules: dependent on plant and transport.

The choice is made according to the ToR: number of storeys, development density, equipment access, desired schedule and budget.

What is included in the “turnkey shell” and where the boundaries of responsibility lie

The exact scope of work is always fixed in the contract and specification. As a rule, for residential projects in Tashkent, a “turnkey shell” means:

• Substructure: site preparation, excavation, foundation, waterproofing.
• Load-bearing frame: columns, beams, walls, trusses (if provided), floor slabs.
• Stair-lift cores: stairs, landings, shafts.
• External walls: load-bearing and self-supporting, including openings for windows and doors.
• Roof structure and preparation for roofing: roof slabs, parapets, embedded parts for MEP systems, and, if required, for future steel structures and fixings for solar panels.

Separately agreed:

• temporary guardrails and permanent roof railings;
• embedded parts for external advertising and wayfinding for the residential complex;
• preparation of locations for future canopies, parking structures, small architectural forms.

A clear ToR on the boundaries of responsibility helps avoid disputes at the interface between the “shell”, MEP and finishes.

Factors affecting shell cost: table

The cost of a “turnkey shell” cannot be the same for different projects. It is influenced by a combination of factors fixed in the ToR and design.

For an accurate estimate based on the ToR, it is important to provide not only total area, but also floor plans, sections and load diagrams.

Typical mistakes of developers and private builders

1. Choosing technology without considering site and logistics
   For example, relying on large precast RC elements with narrow access roads and crane limitations.

2. No clear ToR on shell boundaries
   Embedded parts, railings, preparation for MEP systems and external elements are not specified.

3. Trying to save on geotechnical surveys and foundation design
   As a result — concrete overuse or, conversely, risks of settlement and cracking.

4. Late decisions on MEP
   Penetrations, recesses and shafts are not incorporated into the structure, requiring cutting and strengthening.

5. Underestimating the impact of schedule on cost
   A tight deadline without budget adjustment leads to site overload and quality losses.

6. Changing layouts after work has started
   Especially critical for RC and modular solutions: any change entails rework and additional costs.

7. Ignoring future extensions and mounted equipment
   No fixing points for façade systems, canopies, rooftop steel structures, solar/PV are provided.

These mistakes can be avoided with a comprehensive ToR and early estimation based on the selected technology.

How we work: estimation based on ToR and configuration options

For residential projects in Tashkent and the regions, we treat the “turnkey shell” as a technological complex, not just a volume of concrete and RC.

Stage 1. Analysis of ToR and initial data

• study the architectural concept, floor plans and sections;
• analyze geotechnical data and site constraints;
• clarify requirements for commissioning dates and construction phases;
• agree on shell boundaries and interfaces with MEP and finishes.

Stage 2. Selection of technology and materials

Options:

• cast-in-place frame with partial use of RC (stairs, floor slabs);
• maximally precast scheme based on RC with cast-in-place rigidity cores;
• combined solutions with modular concrete blocks (shafts, bathrooms);
• preparation of embedded parts for steel structures, canopies, railings, support trusses.

At this stage, a preliminary schedule and cost estimate are prepared with key assumptions indicated.

Stage 3. Detailing and construction schedule

• work out structural joints and embedded elements;
• agree on work sequencing and material deliveries;
• prepare a construction schedule, taking into account weather conditions and logistics.

Stage 4. Execution and control

• organize works according to the selected technology;
• control compliance of actual volumes with the design;
• if necessary, adjust solutions in agreement with the client.

At each stage, the client understands how the selected technology affects schedule and budget.

FAQ on the “turnkey shell” technology

1. Can cast-in-place and precast RC be combined in one project?
Yes, this is a common approach: cast-in-place frame and rigidity core, with floor slabs and stairs made of precast RC. The specific scheme is selected based on calculations and the ToR.

2. Which is faster: cast-in-place or precast RC?
With well-organized logistics and a prepared site, precast RC allows faster vertical progress. But if there are limitations on access roads and crane equipment, cast-in-place can be more efficient.

3. When does it make sense to consider modular concrete solutions?
When the project is standard, with high layout repeatability and tight commissioning deadlines. It is important to incorporate modular technology already at the concept stage.

4. Is it possible to estimate shell cost in advance without a full design?
An indicative range can be obtained from high-level parameters (area, number of storeys, technology), but for an accurate estimate based on the ToR, plans, sections and geotechnical data are required.

5. What is usually not included in the “turnkey shell”?
As a rule, internal MEP, final finishes, part of façade systems and landscaping. But the boundaries can be expanded or reduced by agreement.

6. How to account in advance for future canopies, railings and rooftop MEP systems?
These are incorporated into the shell design through embedded parts, mounting platforms and reinforced zones. It is important to provide requirements for these elements at the ToR stage.

7. How much does technology choice affect the building’s performance characteristics?
With proper design and execution, all three approaches provide the required reliability. The differences relate more to layout flexibility, construction speed and cost.

8. Can the technology be changed after foundation works have started?
Theoretically yes, but in practice this almost always leads to redesign and additional costs. It is better to decide on the technology before starting the substructure.

Requesting an estimate

To obtain a “turnkey shell” estimate for a residential project in Tashkent or the region, it is important to prepare initial data. This will allow selection of the optimal technology (cast-in-place, RC, modular solutions or their combination) and provide realistic timelines.

For an estimate request based on the ToR, please specify:

• city and construction address/district;
• project type (apartment building, aparthotel, townhouses, etc.);
• total area and intended number of storeys;
• architectural plans and sections (if available);
• results of geotechnical investigations (if available);
• desired start and completion dates for shell works;
• preferred technology (if already selected) or a request to compare options;
• requirements for preparation for MEP systems, canopies, steel structures and solar/PV;
• cooperation format (general contractor, subcontractor, contract manufacturing of individual elements).

Provide this data and submit a request for an estimate — based on it, a techno-economic proposal and construction schedule for your project can be prepared.