You are considering a floor extension but aren't sure — can your building handle it? How much does it really cost? How quickly will it pay for itself? This article is a practical guide for commercial property owners: a building readiness checklist, real 2026 prices, an ROI calculation, and 7 contractor selection criteria. No marketing — just engineering facts.
- Turnkey price — from 350 $/m² (technical floor) to 430 $/m² (full floor)
- Payback — 3–5 years when leased out
- 40–60% cheaper than new construction
- Suitable for 90%+ commercial and administrative buildings
- Business does NOT stop — "dry" technology, no vibrations
- Required: technical survey before starting (ReadyCon — free of charge)
Checklist: Is Your Building Ready for an LGSF Extension?
A technical survey is required before any extension, but a preliminary assessment can be done on your own. Below are 8 criteria that an engineer checks first. If your building meets at least 6 out of 8, an LGSF extension is most likely feasible.
- Building age under 60 years. Buildings from the 1960s–2020s have sufficient structural reserves. Older ones require additional assessment.
- Up to 5 floors. LGSF extensions on 1–5 story buildings are performed using standard methods. 6+ floors require individual engineering calculations.
- Foundation — strip, pile, or slab. All three types typically have a 20–50% reserve per DBN V.2.1-10:2018.
- Walls — no through-cracks. Hairline cracks (up to 0.3 mm) are acceptable. Through-cracks signal foundation issues.
- Floor slabs — reinforced concrete panels or monolithic. These can withstand the installation loads of LGSF elements.
- Roof — flat or gable. Flat is ideal (minimal demolition). Gable requires demolition, adding +5–10% to the budget.
- Utilities — connection is possible. An extension requires HVAC, electrical, and plumbing connections from existing networks. If networks are at capacity limits, upgrades may be needed.
- Loads > 500 kg/m² — NOT suitable. Heavy industrial equipment or large spans (>12 m) require concrete or welded steel framing.
Key point: If your building is a typical commercial property (office, retail, clinic, hotel) under 60 years old and up to 5 floors — in 90%+ of cases, an LGSF extension is feasible. The definitive answer comes from a technical survey (ReadyCon performs it free of charge at the consultation stage).
Check Your Building for Free
An engineer will visit your site within 1–3 days, perform a preliminary inspection, and provide a conclusion: whether your building is suitable for an extension and what maximum area you can gain.
How Much Does an LGSF Extension Cost in 2026?
The turnkey cost of an LGSF extension in 2026 ranges from 350 to 650 $/m² depending on the type and complexity. This is 40–60% cheaper than new construction, since the foundation already exists and utilities are connected from existing networks.
| Extension Type | Price from, $/m² | Timeframe | Ideal For |
|---|---|---|---|
| Technical floor | 350 | 60–90 days | Server room, ventilation, equipment |
| Mansard | 380 | 60–120 days | Coworking, studio, apartments |
| Full floor | 430 | 90–150 days | Offices, retail, hotels, clinics |
| 2-floor extension | 430 | 120–180 days | Maximum area expansion |
| Reconstruction + extension | individual | 120–180 days | Roof replacement + additional floor |
What Is Included in the Turnkey Price
- Included: design, LGSF frame manufacturing, delivery, installation, 150 mm insulation, facade, roofing, interior finishes, commissioning certificate.
- NOT included: foundation reinforcement (if needed — from $30,000), engineering networks (HVAC, electrical, plumbing — from $20/m²), elevators, furniture.
LGSF Extension vs New Construction — Which Is Cheaper?
An extension eliminates the 3 most expensive items in new construction: the land plot (from $50/m² in cities), foundation (from $80/m²), and main utility connections. Together, that amounts to $370+/m² in savings.
| Cost Item | LGSF Extension | New Construction |
|---|---|---|
| Land plot | $0 (already available) | from $50/m² |
| Foundation | $0 (80% without reinforcement) | from $80/m² |
| Frame + finishes | from $430/m² | from $500/m² |
| Utilities | from $20/m² (connection) | from $80/m² (from scratch) |
| Permits & documentation | from $5,000 | from $10,000 |
| TOTAL | from $430/m² | from $800/m² |
Key point: An LGSF extension is 40–60% cheaper than new construction. The biggest savings come from the foundation and land. For a 300 m² area, the difference amounts to $111,000+.
Payback: When Does the Extension Pay for Itself?
A floor extension is an investment with a 3–5 year payback. That's faster than residential real estate (8–12 years) and significantly faster than a bank deposit. Let's calculate using a real example.
ROI Calculation: 300 m² Office Extension in Dnipro
| Extension area | 300 m² |
| Type: full floor | $430/m² |
| Turnkey cost | $129,000 |
| Office rent in Dnipro | $8–12/m²/month |
| Annual income (avg. $10/m²) | $36,000/year |
| Operating expenses (~15%) | −$5,400/year |
| Net income | $30,600/year |
| Payback period | 4.2 years |
An Extension Increases Property Value
Beyond rental income, an extension increases the market value of the entire building. Typical effect: an investment of 15–25% of the current property value yields a 40–60% increase in value. Additional bonus: an updated facade and roof enhance the attractiveness of existing spaces and allow you to raise rental rates by 10–15%.
Key point: Payback of 3–5 years when leased. Net ROI — 24–28% annually. For comparison: bank deposit — 10–14%, residential real estate — 8–12% annually.
Before & After Case Studies: Real ReadyCon Projects
Over 16+ years, ReadyCon has completed more than 600 LGSF extension projects across Ukraine. Each case below is a real story with specific numbers: area, timeframe, budget, and result.
Case 1: Office Building, Dnipro — +290 m² Without Reinforcement
| Building | 2-story office building from the 1990s |
| Extension area | 290 m² |
| Type | Full 3rd floor (offices) |
| Timeframe | 3.5 months turnkey |
| Foundation reinforcement | Not required (35% reserve) |
| Business | Continued operating without interruption |
The survey revealed a 35% load-bearing capacity reserve in the foundation. The 3rd floor LGSF frame with full interior finishes added a load of 95 kg/m² — the foundation handled it without any additional work. The client gained +290 m² of leasable office space.
Case 2: Commercial Building in City Center — 400 m² in Dense Urban Area
| Area | ~400 m² |
| Type | Roof reconstruction + extension |
| Challenge | Dense urban setting, crane inaccessible |
| Solution | Manual LGSF installation (elements up to 25 kg) |
The main challenge — adjacent buildings in close proximity made crane access impossible. The LGSF advantage: each element weighs up to 25 kg — manual hoisting by winch and installation without heavy machinery. This would be impossible with concrete or masonry.
Case 3: Private House — Mansard Without Relocation
| Building | Private house, aerated concrete |
| Type | LGSF mansard floor |
| Key feature | Family remained in the house |
| Frame installation time | 12 days |
The client wanted to add a mansard without relocating the family. LGSF is a "dry" technology: no concrete pouring, no dust, no vibrations. The frame was installed in 12 days, and the family stayed home throughout the entire construction process.
Case 4: Shopping Center — 2-Floor Extension
| Building | Single-story shopping center, concrete frame |
| Type | 2-floor extension (offices + retail) |
| Load | 190 kg/m² (2 LGSF floors) |
| Comparison | 1 concrete floor = 150–250 kg/m² |
Two LGSF floors add a load of 190 kg/m² — comparable to a single concrete floor. The client doubled the usable area of the shopping center without foundation reinforcement. First-floor tenants continued operating throughout the entire construction period.
5 Common Mistakes in Floor Extensions
Mistakes in floor extensions cost from $20,000 to a complete project shutdown. Here are the 5 most frequent — and how to avoid them.
Mistake 1: Extension Without a Technical Survey
The contractor says: "I can see the foundation will hold." Without lab testing and load-bearing capacity calculations, that's just a guess. Result: cracks, deformations, structural emergency.
Solution: a survey with an official report per DBN V.2.1-10:2018. ReadyCon performs it free of charge.
Mistake 2: Choosing a Contractor Based on the Lowest Price
A price of $250/m² instead of $430/m² isn't a "bargain." It means thinner profiles (0.6 mm instead of 1.0 mm), less insulation (50 mm instead of 150 mm), no design documentation, and no permits.
Solution: compare the turnkey scope, profile thickness, galvanization class, and availability of design documentation.
Mistake 3: Ignoring Permits and Documentation
"We'll build first — then legalize it." An unauthorized extension = fines + forced demolition + inability to sell or lease.
Solution: permit documentation runs in parallel with production. ReadyCon manages the entire process.
Mistake 4: Concrete or Masonry Instead of LGSF
A concrete floor (150–250 kg/m²) almost always requires foundation reinforcement (from $30,000). Plus: business shutdown for 3–6 months, no winter installation.
Solution: LGSF (25–40 kg/m²) = 80% without reinforcement, business continues, installation 365 days/year.
Mistake 5: Multiple Subcontractors Instead of One
One designs, another manufactures, a third installs, a fourth finishes. Result: mismatches, delays, blame-shifting, cost overruns of 20–40%.
Solution: a single full-cycle contractor. ReadyCon: survey → design → factory → installation → handover.
Key point: The main cause of problems is trying to save on surveys and documentation. The correct sequence: survey → design → permit → production → installation → handover. And all done by a single contractor.
Learn more about common mistakes: 7 Common Mistakes in Commercial Building Reconstruction.
How to Choose a Contractor for an Extension: 7 Criteria
A floor extension is not simply "building some walls." It is an engineering project that includes surveying, load calculations, manufacturing, installation, and permit documentation. Here are 7 questions you need to ask every contractor.
-
Do they have in-house manufacturing?
A reseller-contractor depends on a third-party factory: timelines are unpredictable, quality is uncontrolled. In-house production = quality control, CNC precision, flexible scheduling. -
How many extensions are in their portfolio?
Extensions are not the same as new construction. Experience with existing structures is essential: surveys, reserve calculations, anchoring to existing walls. Minimum — 10+ completed extensions. -
Do they provide a full cycle?
The right contractor: survey → design → manufacturing → installation → finishes → handover. One contract, one point of responsibility, one dedicated engineer. -
Is the price fixed in the contract?
"From $300/m²" without details = the price will increase by 30–50% during the project. Demand an itemized estimate and a fixed total price. -
What is the payment schedule?
80% upfront is a risk for the client. The correct approach: milestone-based payments tied to completed work stages (30/30/30/10 or similar). -
Do they handle permit documentation?
Project expert review, construction passport, construction works permit, commissioning certificate — the contractor should manage the entire process, not leave the client alone with bureaucracy. -
What warranty do they offer?
Minimum 5 years on workmanship. Plus: LGSF frame warranty (50+ years with Z275), insulation (50+ years), facade materials (25+ years).
Sources
- DBN V.2.1-10:2018 — Foundations of buildings and structures
- DBN V.2.6-198:2014 — Structures of buildings from thin-walled steel profiles
- DBN V.1.1-7:2016 — Fire safety of construction objects
- ReadyCon Engineering design department data — 600+ completed projects, 2009–2026
The question "Is my building suitable for an extension?" is a matter of engineering assessment, not marketing. In 90% of cases the answer is yes, but only after proper calculations. We always start with the numbers — loads, reserves, maximum allowable area. And only then — a commercial proposal.
Frequently Asked Questions About LGSF Extensions
Yes, in most cases. Buildings from the 1960s–2000s were designed with a 20–50% load-bearing capacity reserve. An LGSF frame (25–40 kg/m²) fits within this reserve in 80% of cases. The exact answer comes from a technical survey — ReadyCon performs it free of charge during the initial consultation stage.
Yes. You need: a technical survey, a project with expert review, a construction passport, and a construction works permit. After completion — a commissioning certificate and registration of the new area. ReadyCon handles the entire permitting process as a single contractor.
An extension provides 100% of the existing floor area (full floor) or 70–85% (mansard due to roof slopes). For example, a 500 m² building can gain 500 m² with a full floor or 350–425 m² with a mansard. The building footprint remains unchanged — no additional land plot is required.
3–5 years when leased out. Example: a 300 m² office extension costs ~$130,000. Office rent in Dnipro is $8–12/m²/month. Net annual income: ~$30,600. Payback (ROI): 4.2 years. When used for your own business — the rent savings are equivalent.
A vertical extension is more cost-effective when: the land plot is limited, maximum area on the existing footprint is needed, or there is no room for horizontal expansion. An annex is preferable when: the foundation is weak (reserve <15%), a separate entrance is required, or large spans (>12 m) are needed. For commercial buildings in cities, vertical extensions are chosen in 70%+ of cases.
Yes. LGSF extensions are suitable for private houses made of aerated concrete, brick, or timber-frame construction. Mansard — from $380/m², full floor — from $430/m². The family stays in the house throughout construction — no vibrations, dust, or wet processes.
LGSF is a year-round technology. Optimal start — spring: design takes 2–4 weeks, production 3–4 weeks, installation falls in May–July. However, LGSF can be installed in winter as well — it is a "dry" technology with no wet processes.
Minimum package: 1) Title documents for the building and land plot. 2) Technical passport (BTI). 3) Technical survey report. 4) Extension project with positive expert review. 5) Construction passport. 6) Construction works permit. ReadyCon assists with preparing all documents.
Yes, positively. Typical increase: +40–60% to the property value with an investment of 15–25% of the current value. Additional effect: an updated facade and roof increase the attractiveness of the entire building and allow raising rental rates by 10–15%.
An extension is 40–60% cheaper. New construction: land + foundation + frame + utilities = from $800/m². LGSF extension: from $430/m² (foundation exists, utilities from existing networks). Savings: $370+/m².
Workmanship warranty — 5 years (specified in the contract). LGSF frame service life — 50+ years (Z275 galvanized coating). Insulation (mineral wool 150 mm) — 50+ years. ReadyCon bears responsibility for the entire project as a single full-cycle contractor.
7 criteria: 1) In-house manufacturing. 2) Portfolio of extensions specifically (10+). 3) Full cycle without subcontractors. 4) Fixed price in the contract. 5) Milestone-based payments (not 80% upfront). 6) Permitting documentation support. 7) Warranty of at least 5 years.
Want to Know If Your Building Qualifies?
Free consultation and preliminary site inspection within 1–3 days. An engineer will assess the extension feasibility and maximum area.
Own production facility: Dnipro, 15A Sicheslavska Naberezhna St.
readycon.com.ua · ReadyCon@ukr.net