Leave the repairs and renovations of condominiums and apartments in Naka, Yokohama City to Kakeru Koumuten Co., Ltd.!

Large-Scale Renovations for Condominiums, Apartments, and Buildings in Naka Ward, Yokohama

Large-scale repair work that can be handled in Naka Ward, Yokohama

Large-scale repairs are not just “exterior wall painting” or “waterproofing,” but a comprehensive repair of the entire building’s deterioration while scaffolding is in place. At Kakeru Koumuten, we can handle all of the following work in-house, ensuring clear responsibility and coordination of the process.

Scope of Major Repairs Determined by Building Diagnosis

It is not guaranteed that all of the above works will be carried out. The extent of the work will be determined based on the results of the building diagnosis. At Kakeru Koumuten, we conduct free on-site surveys to confirm the following, and we will propose the scope of work based on a deterioration diagnosis report with photographs.

Reasons Kakeru Koumuten is Chosen for Large-Scale Renovations in Naka Ward, Yokohama City

The reason why we can be entrusted with large-scale repairs in Naka Ward is partly because “Kakeru Koumuten has a base in Yokohama City”, but also because of our “initiatives in large-scale repair work that cannot be imitated by other companies”, which have received high praise from many customers.

1. Equipment Specialized for Exterior Renovations

At Kakeru Koumuten, we have prepared the following warehouses and material storage areas to provide low-cost, high-quality exterior wall painting and waterproofing work for large-scale repairs. We have established five bases centered around Yokohama City for material storage and showrooms.

In-house Ownership of Scaffolding Materials

We own the scaffolding materials necessary for temporary scaffolding required for large-scale repairs and can assemble the scaffolding ourselves.
By not outsourcing scaffolding work and using our own scaffolding team, we can reduce scaffolding construction costs and respond quickly and flexibly.
We own scaffolding materials for approximately 100 detached houses!

Storage of Materials in Our Large In-house Warehouse

We store paints and substrate repair materials used for exterior renovations. By ordering a large quantity of materials at once, we can procure materials at a lower cost! Additionally, we always have stock available, so we can respond quickly even in emergencies!

In-house Sorting of Waste Materials

In large-scale repairs, various waste materials such as waste paint, metal, and wood are generated. At Kakeru Koumuten, we sort and recycle waste materials in-house, leading to cost reductions in waste disposal fees.

Showroom Dedicated to Exterior Renovations

In the showroom, you can not only have meetings but also check actual samples and colors of exterior materials. You can also perform color simulations for exterior wall painting and check thermal insulation properties using a thermal insulation testing machine!

2. Cost Reduction through In-House Management and Construction

One of Kakeru Koumuten’s major strengths is in-house management and construction.

By managing everything from inquiries to project completion in a unified system by Kakeru Koumuten, we can keep costs down while ensuring high-quality large-scale repairs. Additionally, a single representative will handle everything from the estimate to project completion. Since the person in charge does not change, whether it’s sales or construction management, smooth communication is possible.

We can handle everything from temporary scaffolding installation to exterior wall painting, substrate repairs, waterproofing work, and tile repairs with complete in-house construction! Those with specialized knowledge and experience will conduct inspections and actual construction for each process!

3. Obtaining Various Permits and Skilled Workers

We have obtained construction business licenses and permits for industrial waste collection and transportation! We also have nationally certified sheet metal and painting skilled workers, and we are confident in our construction techniques. We can also handle large-scale roofing work for factories! We have qualified personnel for asbestos work supervisors and building material asbestos surveyors, so we can manage asbestos-containing roofing materials and conduct preliminary surveys.

4. Warranty and Aftercare

Large-scale repair work comes with warranties for most jobs, including “painting work,” “substrate repair work,” and “waterproofing work”!
Aftercare maintenance is available every year, and we send out notification DM each year.

5. Flexible and Prompt Response

Our company is equipped to handle various troubles and situations in apartments and condominiums.

We can also address exterior walls and rooftops that cannot be checked from high places using a drone! During leak investigations, we can use a thermal imaging camera to help identify the cause of leaks!

We will respond according to your wishes. We also accept emergency measures for sudden leaks! We will promptly attend to urgent requests and emergencies!

6. Staff Development

Our staff create various models for skill improvement and conduct practical training. Since different sites require various processing and techniques, we provide regular skill enhancement education to ensure each staff member can respond appropriately. We also educate on points of caution and inspection areas for each stage of large-scale repair work.

7. Consideration for Residents and Neighbors

During large-scale renovation work, we will not only notify residents and greet nearby residents, but also install a bulletin board at the entrance to display the construction schedule and notices! Additionally, we will thoroughly educate visitors on manners to minimize inconvenience to residents and neighbors.

8. Strict Quality Control

Each process will be inspected by a responsible person, and detailed construction photos will be taken. We will use a film thickness inspection machine and check sheets to ensure that there are no inspection omissions. During exterior wall painting and waterproofing work, we will check the number of used paint cans to confirm that the specified amount of paint is being used, and by ordering paint in-house, we will prevent construction defects in advance. Of course, we will also take photos of the used paint and report them.

9. Exterior Wall Painting Color Simulation

9-1 Self Color Simulation

Our simulations can be created from actual photos of your apartment or building!You can also perform simulations on your smartphone or computer. By simulating and then changing to a two-tone color or making an image change, we hope to enhance the stylish appearance and contribute to an increase in occupancy rates! Of course, we can also arrange paint samples for actual color confirmation.

* In Naka Ward, there are areas subject to landscape planning notifications and consultations (Kannai, Minato Mirai 21 Central, Minato Mirai 21 Shinko, Yamate) and scenic districts (Yamate, Honmoku, Negishi), where notifications or permits may be required when changing the color of exterior walls. There are also areas with district plans and building agreements. Having a color simulation screen can help facilitate explanations at management association meetings and neighborhood associations.

9-2 Confirm the actual color with a trial paint!

You can order samples of the paint you are considering and conduct trial painting on your exterior wall. By conducting a trial paint, you can confirm the actual color and gloss!

9-3 Exterior Renovation Simulation

Exterior simulations for apartments and condominiums are also possible!
・Exterior wall color simulation (two-tone colors are also possible)
・Simulation for applying metal siding
・Simulation using accent materials such as cornices and louvers
・Simulation for roof painting and roof replacement work

With the exterior renovation simulation, you can minimize the risk of failure in image changes! We hope that renovating the appearance of your apartment or condominium will help increase occupancy rates.

Cost Estimates for Major Repairs in Naka Ward, Yokohama City

The cost of major repairs varies greatly depending on the size of the building, deterioration condition, scope of work, and materials used. First, please refer to the national average based on public statistics, then to our company’s estimates based on construction performance by size, and finally to examples of unit prices for each project.

The national average for condominiums is 750,000 to 1,500,000 yen per unit

According to a survey conducted by the Ministry of Land, Infrastructure, Transport and Tourism, which compiled 818 construction cases (FY 2021), approximately 70% of the costs for major repairs are concentrated in the range of 750,000 to 1,500,000 yen per unit, with the most common price range being 1,000,000 to 1,250,000 yen. Yokohama City also indicates on its official website that the cost is approximately 1,000,000 to 1,300,000 yen per unit. Please note that the amounts in this survey do not include consumption tax and common temporary construction costs, so they differ from the current total construction costs including tax.

Source: Ministry of Land, Infrastructure, Transport and Tourism “Survey on Large-Scale Renovation Work for Condominiums in FY2021” (200 companies, 818 cases) / Yokohama City “Market Prices for Large-Scale Renovation Costs and How to Address Shortfalls in Repair Reserves” *Amounts do not include consumption tax or common temporary construction costs. Percentages may not total 100% due to rounding and non-responses.

Breakdown of Construction Costs (Where the Money Goes)

Source: Ministry of Land, Infrastructure, Transport and Tourism “Survey on Large-Scale Renovation Work for Condominiums in FY2021” (Second survey of large-scale renovation work. Overall average is construction-related 59.0%, temporary construction 22.3%, miscellaneous expenses 9.9%). *The total does not equal 100% because equipment-related work, exterior works, and others are included. This is an average value and is not a criterion for judging the appropriateness of individual estimates.

Cost Estimates by Building Size (Scaffolding, Substrate Repair, Exterior Painting, Waterproofing, Sealing)

*The above estimates are based on Kakeru Koumuten’s construction records and may vary depending on the presence of roofing work, ironwork, plumbing, etc. For apartments, please also consider the amount calculated by multiplying the national statistics (750,000 – 1,500,000 JPY per unit) by the number of units.

Breakdown of Costs for Temporary Works, Substrate Repair, Exterior Walls, and Waterproofing

The estimate for large-scale repairs is broadly divided into “Temporary Works,” “Substrate Repair,” “Sealing,” “Exterior Painting,” “Waterproofing,” and “Miscellaneous Expenses.” Before comparing total amounts, please check what each item includes, how much, and at what cost.

Examples of Unit Prices for Repair Work

*Costs and warranty periods vary depending on shape, quantity, substrate condition, and type of materials. If you would like a detailed estimate, please feel free to contact us. Estimates are completely free.

Select Paint and Waterproofing Grades Based on “Years Until Next Repair”

“Good paint does not equal the right choice.” The best way to choose is to align when the next major repair will be with the lifespan of the materials to avoid waste.

*The estimated lifespan is a general guideline and may vary depending on sunlight, location, and substrate condition. For buildings close to the sea, where salt air affects surfaces, choosing high-weather-resistant paint and specifications that include rust prevention for metal parts after washing off salt will change durability.

Guidelines for Repair Reserve Funds and Options When Insufficient

According to the Ministry of Land, Infrastructure, Transport and Tourism guidelines, the guideline for repair reserve funds is indicated as a monthly amount per exclusive area. Additional charges are necessary if there is a mechanical parking lot.

Source: Ministry of Land, Infrastructure, Transport and Tourism “Guidelines on Repair Reserve Funds for Condominiums” (Reiwa 6, June Revision, PDF) / National average is 13,378 JPY per unit per month (Reiwa 5 Fiscal Year Comprehensive Survey of Condominiums)

In the Reiwa 5 Fiscal Year Comprehensive Survey of Condominiums, 36.6% of management associations responded that “the repair reserve fund is insufficient compared to the plan.” There are four main options when insufficient.

Subsidies, Tax Systems, and Loans to Confirm for Large-Scale Renovations in Naka Ward, Yokohama City

Both Yokohama City and Kanagawa Prefecture do not have subsidies specifically for large-scale renovation work itself. The available options can be broadly categorized into the following four types. The eligibility and application status of these systems may change even during the fiscal year, so please be sure to check with our company or the respective offices before contracting or starting work. (As of October 8, 2026)

① Condominium Longevity Promotion Tax System (Reduction of Fixed Property Tax)

If large-scale repairs (including exterior painting, floor waterproofing, and roof waterproofing) that contribute to the longevity of certain qualifying condominiums are carried out, the fixed property tax amount for the following year will be reduced by half (up to the equivalent of 100㎡ per unit; urban planning tax is not included).

② Support for Condominium Management in Yokohama City (Management Associations Start Here)

The support system in Yokohama City is mostly based on registration in the “Yokohama City Condominium Registration System” (free). Management associations that are not yet registered should start here.

Source: Yokohama City “Support and Subsidy System List by Concerns for Condominium Management Associations” / Long-term Repair Plan Creation Promotion Model Project / Condominium Advisor Dispatch / Seismic Reinforcement Subsidy for Specific Buildings / Yokohama Condominium Portal

③ Management Plan Certification System (Entry for Tax and Interest Rate Benefits)

This is a system certified by Yokohama City. Upon certification, the loan interest rate from the Japan Housing Finance Agency is reduced by 0.2% per year, preferential interest rates for Flat 35 are available, and it meets one of the requirements for the Long-Life Promotion Tax System (certification alone does not guarantee tax reduction). The main criteria include holding general meetings at least once a year, establishing management regulations, separate accounting for management fees and repair reserves, ensuring that the amount in arrears is within 10% of the total, and “having created or reviewed a long-term repair plan that includes large-scale repair work at least twice and has a planning period of over 30 years within the last 7 years.”

*Fees include a system usage fee of 10,000 yen + a city application fee of 3,900 yen, among others. It takes 2 to 3 months from application to certification. The certification is valid for 5 years.

④ National Energy Saving Support | Housing Energy Saving 2026 Campaign

Changes for Fiscal Year 2026The “Child-Rearing Green Housing Support Project” for Fiscal Year 2025 has been abolished and reorganized into the successor “Mirai Eco Housing 2026 Project.” Additionally, the “Long-Term Excellent Housing Renovation Promotion Project” will end in Fiscal Year 7 and will not be implemented in Fiscal Year 8. Please be careful not to create financial plans based on outdated information.

Mirai Eco Housing 2026 Project

Advanced Window Renovation 2026 Project

⑤ Kanagawa Prefecture Subsidies (Applications for Fiscal 2026 have ended)

* The Existing Housing Energy Efficiency Renovation Subsidy does not cover common areas of rental apartments or units not occupied by the owner.

⑥ Loan System (Housing Finance Agency Condominium Sumairu Loan)

If the management association borrows funds for large-scale repairs, they can utilize the Housing Finance Agency’s “Condominium Common Area Renovation Loan (Condominium Sumairu Loan).”

Source: Housing Finance Agency “Condominium Sumairu Loan” (Official)

Cases where fire insurance can be used and cases where it should not be used

Building conditions and repair points in Naka Ward, Yokohama City

Naka Ward, Yokohama City, has developed as an urban area since the opening of Yokohama in 1859 (Ansei 6), and the ward system was implemented in October 1927 (Showa 2), making it the center of Yokohama. The terrain is divided into reclaimed land surrounded by the Ooka River and Nakamura River, coastal reclaimed land, and three hilly areas: Nogeyama, Iseyama, and Yamate Plateau, and Negishi Plateau. Locations with different characteristics, such as the business and commercial center of Kannai and Minato Mirai, residential areas on the plateaus of Yamate and Negishi, and logistics and industrial areas in Honmoku and the coastal region, are all found within the same ward, which serves as a starting point for considering large-scale repairs in Naka Ward.

Source: Yokohama City “Population News” (Estimated Population and Number of Households as of October 1, Reiwa 8) / Naka Ward Statistical Handbook (2025 Edition) (Daytime and Nighttime Population) / Yokohama City Housing Policy Council Materials (Reiwa 1 Year Basic Survey on Condominiums) / Yokohama City “District Plan (Naka Ward)” / Yokohama City “Building Agreement (Naka Ward)”

We will also confirm the composition of households and population. According to estimates as of October 1, Reiwa 8, there are 154,572 people and 90,841 households, with an average of about 1.7 people per household (the overall average for Yokohama City is about 2.1 people, calculated from the estimated population and number of households). The proportion of the elderly population (65 years and older) is 23.9% (as of January 1, Reiwa 7), and the foreign population is 18,773, accounting for 12.24% of the total population (as of March 31, Reiwa 7). The daytime to nighttime population ratio is 168.7, indicating that many people gather from outside the ward during the day. Additionally, in Kannai and outside Kannai, the proportion of collective housing among all buildings has increased from 4.6% in 1992 to 9.1% in 2013. These figures represent the entire ward and do not reflect the situation of individual building residents or tenants.

Source: Naka Ward Statistical Handbook (2025 Edition) “Indicators” / Same “Foreign Population” / Naka Ward Urban Development Policy (March Reiwa 2) “Formation and Current Status of Naka Ward”

Naka Ward’s Buildings are Divided into “Four Faces”

The buildings in Naka Ward reflect the history of urban development, which has become a characteristic of each location. The type of significant repairs required in your building’s next major renovation will vary depending on its location. Please note that the history of reconstruction and large-scale renovations differs for each building, so consider the age of the building as a guideline.

Source: Naka Ward Historical Timeline (Ward system established in 1927, Port opened in 1859, Honmoku Citizen Park opened in 1969, Minato Mirai Line opened in 2004, direct service started in 2013, completion of Minami Honmoku Wharf in 2015) / Naka Ward Urban Development Policy (March 2020) (Topography, Great Fire of 1866, Great Kanto Earthquake of 1923, Land Use 2013, Historical Buildings) / Yokohama City “District Plan (Naka Ward)” / Yokohama City “Building Agreement (Naka Ward)” / Yokohama City “List of Scenic Districts and Town Names”

Four Unique Factors in Naka Ward that Damage Buildings

The contents of large-scale repairs vary depending on the location of the building. When investigating buildings in Naka Ward, we particularly check the following four factors. While I will discuss based on trends across the ward, the actual conditions differ for each building, so we will always confirm on-site.

Source: Naka Ward Urban Development Policy (March 2020) / Yokohama City “Flood Hazard Map (Naka Ward Version)”・“What is a Flood Hazard Map?” / Yokohama City “Q&A on Liquefaction Phenomena” / Yokohama City “Frequently Asked Questions about Landscape Regulations”・“Yamate District Landscape Plan and Urban Landscape Consultation Area”・“Kannai District Landscape Plan and Urban Landscape Consultation Area” / Yokohama City “List of Scenic Districts by Town Name”

Key Issues to Consider When Advancing Construction in Naka Ward

* Kakeru Koumuten has five locations in Yokohama City, including a showroom and material storage, and we respond to inquiries throughout Naka Ward, including Kannai, Isezakicho, Motomachi, Yamate, Honmoku, and Minato Mirai.

Signs of Deterioration Requiring Major Repairs and Timing

Generally, major repairs are recommended every 12 to 15 years. According to the Ministry of Land, Infrastructure, Transport and Tourism’s survey, the actual repair cycle is most commonly 13 years, with about 70% falling within the 12 to 15 year range, and the cycle tends to shorten with each occurrence. However, the actual determination should be based on the condition of deterioration rather than just the number of years, so if you observe symptoms like those listed below, we recommend an early on-site investigation.

Estimated Repair Cycles by Location (Ministry of Land, Infrastructure, Transport and Tourism Guidelines)

*The above are reference examples from the guidelines and are not uniform construction deadlines. Actual cycles will be set according to the specifications, location conditions, and deterioration status of the building.

Source: Ministry of Land, Infrastructure, Transport and Tourism “Guidelines for Creating Long-Term Repair Plans” (Revised June 2024, PDF) / Ministry of Land, Infrastructure, Transport and Tourism “Survey on Large-Scale Repair Work for Condominiums in FY2021”

Examples of Large-Scale Renovation Work

This is a case of exterior renovation work on a mixed-use building undertaken by Kakeru Koumuten. The building had leaks occurring in several places, and it was renovated by combining clear waterproofing for the tile exterior walls and waterproofing for the roof.

Exterior Renovation Work on a Mixed-Use Building (Tile Exterior Wall Waterproofing + Roof Waterproofing)

Customer Feedback

Process from On-Site Investigation to Completion of Construction

From inquiry to completion of construction and aftercare, one representative will consistently handle your case. In the case of management associations, a resolution at the general meeting is necessary, so it is advisable to start moving 1 to 1.5 years before the desired start date to proceed with ample time.

1. Contact Us (Free) Please reach out via phone, form, or LINE. If you have estimates from other companies, it’s fine to just present those.
2. On-site Investigation & Building Diagnosis (Free) We will conduct a survey of the exterior walls, check for cracks, sealing, and waterproof layers, and if necessary, investigate the roof, high places, and leak areas using drones or thermal imaging. For properties in Naka Ward, we will also check for rust on iron parts of buildings near the sea, potential flooding and storm surge on the premises, the condition of slopes and retaining walls, as well as access routes and parking.
3. Submission of Investigation Report & Estimate We will provide a deterioration diagnosis report with photos and an estimate detailing quantities, methods, and materials for each work item. Multiple plan proposals are also available.
4. Plan Decision & Contract Confirm colors using color simulations, paint samples, and trial painting. For management associations, we can assist in preparing materials for general meetings. In areas subject to landscape plans, scenic districts, district plans, and building agreements, we will also explain the procedures and color considerations.
5. Notification to Residents & Neighbors We will distribute construction notices, visit neighbors to greet them, and set up a bulletin board at the entrance (with a schedule and laundry information). If temporary relocation of parking is necessary, adjustments will be made at this stage.
6. Installation of Temporary Scaffolding & Various Works Our in-house scaffolding team will set up the scaffolding, followed by high-pressure washing, substrate repair, sealing, exterior wall painting, tile repair, waterproofing, and work on iron and ancillary parts in that order. A supervisor will inspect each stage and take construction photos.
7. Completion Inspection, Scaffolding Dismantling & Handover We will confirm the finish in the presence of the customer and provide construction photos, a report on the paint used, and a warranty certificate.
8. Aftercare Maintenance We will send out annual DM notifications, and inspections can be conducted every year. Simple repairs such as partial sealing are provided free of charge.

Resident Communication, Approval for Additional Work, Inspection Reports

Equally important as the construction itself is “when, what, and with what materials we report”. At Kakeru Koumuten, we provide materials and reports in the following four scenarios.

* For management associations, it is smooth to decide in advance who will approve additional work (such as the chairman or repair committee) and the estimated amount that requires approval before the contract.

How Will Life Be During Construction? Impact on Residents

For large-scale repairs, the principle is to proceed while you continue to live in your home. However, there will be some limitations to your daily life while scaffolding is in place. Most troubles can be prevented by providing prior notice, so Kakeru Koumuten Co., Ltd. thoroughly explains and posts information before construction begins.

How to Choose a Large-Scale Repair Contractor and Ordering Method

There are many large-scale repair contractors that cover the Naka Ward of Yokohama City, and you may be unsure which contractor to choose. When requesting renovations for apartments, condominiums, or buildings, please check the following four points.

Have Extensive Experience in Large-Scale Repairs

Large-scale repair contractors often have websites that showcase their exterior renovation achievements. If they provide detailed explanations of repair work with photos, it gives you peace of mind as a reference when you actually request their services.

Using Google and review sites to evaluate large-scale repair contractors can also be effective when comparing them! Be cautious if there are many negative reviews. If there are few reviews, also check their construction achievements, explanation content, and management system.

Large-scale repair work involves not only the construction itself but also the potential for troubles with residents and nearby neighbors. Therefore, it is necessary to post updates on the progress of the work and information about laundry on bulletin boards to prevent issues before they arise. Kakeru Koumuten Co., Ltd. specializes in exterior work, and we receive many requests for exterior renovations of apartments and condominiums.

Check for Warranty and Aftercare Services

When choosing a large-scale repair company, make sure to check for warranty availability. If any issues such as leaks occur after the work is completed, having a leak warranty from the contractor ensures that repairs can be made at no cost, providing peace of mind! A company that offers a warranty is often a sign of confidence in their work, serving as a criterion for selecting a contractor.

Warranty periods vary by contractor and the nature of the work, but typically range from 1 to 10 years. Emergency repairs or partial fixes often do not come with a leak warranty. Some contractors also provide aftercare services separate from the warranty, so be sure to check for warranty and aftercare services.

At Kakeru Koumuten Co., Ltd., we send out annual direct mail for aftercare maintenance, allowing for yearly inspections. We also provide free assistance for simple repairs such as partial sealing.

Obtain Estimates from Multiple Contractors (at least 3 companies)

When requesting large-scale repairs, be sure to obtain estimates from multiple contractors. It is important to get estimates from at least three companies and compare their quotes and reports! Even for the same work, costs can vary between contractors, as can warranties and aftercare services. Additionally, obtaining multiple estimates makes price negotiations easier.

When comparing estimates, consider not only the cost but also the “items in the estimate,” “methods and materials for substrate repairs and exterior wall painting,” and “confirmation of the process” to make an informed decision! If the quality of auxiliary materials is low or if steps are skipped, costs can be reduced, so avoid making decisions based solely on price. Especially since substrate repair work can be difficult to assess from appearance alone, ensure that the repair method is suitable for the condition of the substrate!

Check This on the Estimate (Checklist)

Confirm whether it is managed in-house

Large-scale repair work includes various tasks such as “substrate repair work,” “exterior wall painting,” “waterproofing work,” and “pipe replacement,” and the plan content changes based on the actual deterioration condition and customer preferences.

Contractors that completely delegate to subcontractors lack knowledge and experience, which may lead to proposals for repairs in irrelevant areas or unnecessary work. If you investigate and then request a subcontractor, it may incur additional time and costs. By having knowledge and experience and managing in-house, responsible construction can be performed at a reduced cost.

Additionally, contractors that delegate to subcontractors may also have delayed responses in case of troubles during construction. It is safer to avoid companies that do not have direct meetings with customers managing the construction. Kakeru Koumuten performs everything from temporary scaffolding setup to exterior wall painting and waterproofing work in-house, managed by knowledgeable and experienced personnel!

There are three ordering methods. The choice affects the approach.

Especially for management associations, it is necessary to decide “how to request” before “which company to hire.” The main ordering methods are the following three.

Collusion and Improper Consulting Issues in Large-Scale Renovations and Self-Defense Measures

Latest 2026 In the large-scale renovation industry, improper orders linked between design consultants and construction companies have long been a problem. The Ministry of Land, Infrastructure, Transport and Tourism issued warnings and notifications to management associations in January 2017 and April 2023, and on September 28, 2026, the Japan Fair Trade Commission announced that it had issued exclusion orders to 38 companies and imposed a total of 1.63788 billion yen in penalties on 37 companies regarding large-scale renovation work commissioned by condominium management associations to design consulting firms in the Kanto region (two design consulting firms were also subject to exclusion orders).

※This content is based on the announcement by the Japan Fair Trade Commission (September 28, 2026).

Three Typical Schemes

Source: Yokohama City “What is collusion in large-scale repair work for condominiums?” / Ministry of Land, Infrastructure, Transport and Tourism “On the Proper Ordering of Large-Scale Repair Work for Condominiums” (Notification dated April 3, Reiwa 5, PDF)

Self-Defense Measures for Management Associations

• Obtain independent estimates from multiple companies.
• Consult with neutral third parties such as condominium management professionals or architects.
• Document the vendor selection process in minutes to ensure transparency.
• Confirm the reasons for unusually low consulting fees.
• Include a penalty clause in the contract for cases of collusion being discovered.
• Avoid concentrating information with a single consultant and verify specifications by the management association itself.

New System in Yokohama City Bid Agency Service for Large-Scale Repair Work

In response to this issue, in October 2025, Yokohama City and the Yokohama Housing Supply Corporation established the “Bid Agency Service for Large-Scale Repair Work.” This system separates the selection of design and construction companies, with the corporation acting as a third party to conduct conditional competitive bidding. The estimated price will not be disclosed, and the process will be conducted in accordance with public works methods.

Source: Yokohama City Press Release (October 16, 2025) / Yokohama Housing Supply Corporation

Frequently Asked Questions about Large-Scale Repairs in Naka Ward, Yokohama

How much does large-scale repair in Naka Ward, Yokohama cost?

For apartments, according to the Ministry of Land, Infrastructure, Transport and Tourism’s survey for the fiscal year 2021, about 70% of cases fall between 750,000 to 1,500,000 yen (excluding consumption tax and common temporary construction costs), with the most common range being 1,000,000 to 1,250,000 yen. Yokohama City also indicates “approximately 1,000,000 to 1,300,000 yen per unit.” Based on our construction records, for a two-story wooden apartment, the cost ranges from 2,000,000 to 4,000,000 yen, for a three-story steel or RC apartment from 4,000,000 to 9,000,000 yen, and for small apartments or mixed-use buildings from 5,000,000 to 15,000,000 yen. The cost varies depending on the condition of the substrate and whether waterproofing or roofing work is needed, so we provide free on-site estimates.

How often should large-scale repairs be conducted?

Generally, a cycle of 12 to 15 years is recommended, and the actual cycle is most commonly 13 years according to the Ministry of Land, Infrastructure, Transport and Tourism’s survey, with about 70% falling within the 12 to 15-year range. However, the decision should be based on the condition of deterioration rather than just the number of years. If deterioration of sealing, tile lifting, or breaks in the waterproof layer are observed, it is advisable to carry out repairs without waiting for the cycle, as this can ultimately reduce costs. For older buildings, the proportion of tile repairs and steel part replacements tends to increase in the second and third rounds of repairs.

How long does the construction period take? Can residents stay during the work?

For apartments, the construction period is typically 3 weeks to 2 months, for small apartments or buildings 1.5 to 3 months, and for apartments with over 50 units about 4 to 6 months. Residents can remain in their homes during the construction. However, while scaffolding is in place, there may be restrictions on drying laundry outside and opening windows, so we take thorough measures to minimize the impact on daily life, including distributing pre-construction notices, providing information on the schedule and laundry on bulletin boards, and strictly adhering to work hours.

How long should I expect from the start of planning to the completion of construction?

For management associations, the process from establishing a repair committee, building diagnosis, contractor selection, to general meeting resolution typically takes 1 to 1.5 years, followed by 3 to 6 months for construction. Overall, it is advisable to plan for about 2 years to proceed comfortably. If using subsidies or tax incentives, please also factor in the time to obtain management plan certification (which takes 2 to 3 months from application to certification).

Are there any subsidies available for large-scale repairs in Naka Ward, Yokohama?

Both Yokohama City and Kanagawa Prefecture do not provide subsidies specifically for large-scale repair work. However, for condominium units, if certain conditions are met, there are reductions in fixed property tax by half under the “Condominium Longevity Promotion Tax System,” subsidies from Yokohama City for deterioration diagnosis and long-term repair planning (half, with a cap of 200,000 yen), and subsidies for barrier-free renovations in common areas (one-third, with a cap of 300,000 yen). If the work includes windows and insulation, it may qualify for “Advanced Window Renovation 2026” or “Future Eco Housing 2026.” The timing of applications and applicants varies by program, so please check the eligibility conditions and application procedures for each program before contracting or starting work.

I heard that fixed property taxes can be reduced through large-scale repairs. Is that true?

It is true if certain conditions are met. Under the Condominium Longevity Promotion Tax System, if a condominium that meets requirements such as being over 20 years old and having more than 10 units conducts large-scale repairs that contribute to longevity (including exterior painting, floor waterproofing, and roof waterproofing), the fixed property tax for the following year can be reduced by half for up to 100 square meters per unit. The eligible period is for work completed between April 1, 2023, and March 31, 2027, and a declaration must be made to the Naka Ward Office within 3 months of completion. For certified management plan condominiums, there are additional requirements such as increasing repair reserve funds, so it is recommended to start preparations more than a year before the work.

Are there any changes to subsidies starting from the fiscal year 2026?

Yes. The national “Child-Rearing Green Housing Support Project” has been abolished and reorganized into the successor “Future Eco Housing 2026 Project.” Management associations and management corporations can also become joint project participants, allowing for insulation renovations in common areas. Additionally, the “Long-Term Excellent Housing Renovation Promotion Project” will end in fiscal year 2025, and it will not be implemented in fiscal year 2026. The “Advanced Window Renovation 2026 Project” has begun accepting bulk applications for apartment buildings starting May 29, 2026 (application procedures are handled by registered contractors). Please be careful not to base your financial plans on outdated information.

What should I do if the repair reserve fund is insufficient?

The options are mainly four: ① Postpone low-urgency work after deterioration diagnosis to the next time, ② Review the scope and specifications of the work, ③ Check support systems such as subsidies, ④ Consider increasing the repair reserve fund or financing from the Japan Housing Finance Agency. The agency’s condominium common area renovation financing does not require collateral, and by obtaining management plan certification and implementing energy-saving and seismic work, the interest rate can be reduced by up to 0.6% per year. Please note that postponing waterproofing and tile peeling measures often ends up being more expensive, so please consult us for a decision on separation.

Can scaffolding be set up on buildings located on sloped or uneven ground, such as on top of retaining walls or on inclined land?

Yes, it can. Naka Ward consists of low-lying areas such as Kannai, the waterfront, and reclaimed land, as well as plateaus like Yamate and Negishi, where residential areas may have sloped or terraced land, and buildings facing narrow roads. Kakeru Koumuten Co., Ltd. owns its own scaffolding materials and has its own scaffolding team, allowing us to plan support and layout of the boards after confirming the site. This is a part where additional costs are likely to arise after seeing the site, so it is important to confirm the delivery route during the estimation stage. We also check the deterioration of retaining walls and slopes and consult on whether they are included in the long-term repair plan.

What will happen to the parking for residents during construction?

Vehicles on the side where scaffolding will be erected will need to be temporarily moved. In buildings with group housing or on-site parking, it may take time to secure a relocation space depending on the number and arrangement of vehicles. Kakeru Koumuten Co., Ltd. will coordinate with you about the availability of nearby coin parking and monthly parking spaces starting 2 to 3 months before construction begins.

Can I freely decide the color of the exterior walls?

This depends on the regulations affecting the building’s site. In Naka Ward, there are areas subject to landscape planning notifications and consultations (Kannai, Minato Mirai 21 Central, Minato Mirai 21 Shinko, Yamate) and scenic districts (Yamate, Honmoku, Negishi), where notifications or permits may be required when changing the color of the exterior. Additionally, there are 17 district plans and 3 building agreements within the ward, and the contents differ by district. You can check what regulations apply to your site at the Yokohama City landscape, scenic district, and building agreement office. Our company will also investigate this during the survey, share the completion image through color simulation, and assist in forming agreements with the management association and neighbors.

Do buildings close to the sea need salt damage measures?

Naka Ward faces Yokohama Port and Tokyo Bay to the east, and the waterfront area is a district with extensive reclaimed land. In buildings close to the sea, salt carried by sea breezes can adhere to exterior walls, metal parts, and fittings, accelerating rust progression. However, the extent of the impact varies depending on the distance from the sea, direction, and height of the building, so it cannot be said that it is universally necessary. We will check the progression of rust on metal parts and fittings during the on-site survey, thoroughly remove salt with high-pressure washing, and propose specifications that include highly weather-resistant paint and rust prevention. Additionally, in low-lying or reclaimed land sites, there are assumptions of flooding, storm surges, and liquefaction, so we will check the Yokohama City flooding hazard map (Naka Ward version) and inspect the waterproofing and condition of equipment around the first floor, basement, and mechanical rooms on-site.

Which should I choose, the responsibility construction method or the design supervision method?

In cases where the number of units is small, the burden of consulting fees becomes heavier, so we believe that the responsibility construction method is often suitable for small to medium-sized buildings. The design supervision method allows for comparison of construction companies under the same conditions since a third party creates the specifications, but it incurs separate consulting fees and requires caution regarding conflicts of interest and collusion risks. Even with the responsibility construction method, verifying price, specifications, and construction status is essential. Kakeru Koumuten Co., Ltd. provides estimates that clearly state quantities, methods, and materials for each construction item, allowing you to compare on the same level as other companies.

How can I detect collusion in large-scale repairs?

There are three typical methods. ① Pre-determining the contractor and having other companies submit only formal high estimates, known as “dummy estimates,” ② A consultant contracts at an extremely low design supervision fee and receives kickbacks from partner companies, creating collusion, ③ Adding a portion of the contract amount as a back margin to the construction cost. Countermeasures include obtaining independent estimates, consulting a neutral third party, documenting the selection process in minutes, and including penalty clauses in contracts. In October 2025, Yokohama City and the Yokohama City Housing Supply Corporation will establish the “Large-Scale Repair Work Bidding Agency Service.”

How many companies should I get estimates from?

I recommend at least three companies. If there are too many, it becomes difficult to compare, and if there are too few, there is no competition. What is important is not the number of companies, but “creating the same playing field before comparing.” By creating a common specification sheet and quantity table and requesting estimates under the same conditions, and by making detailed breakdowns mandatory instead of accepting “one set” notation, it becomes clear whether the price differences are due to variations in scope or unit prices.

What is the difference if we have our own scaffolding?

In large-scale repair projects, temporary construction accounts for about 20% of the total cost (according to the Ministry of Land, Infrastructure, Transport and Tourism’s fiscal year 2021 survey). By not outsourcing scaffolding work, we can easily control costs in this area, and our in-house scaffolding team can flexibly respond to sudden changes in the schedule or additional work. Kakeru Koumuten Co., Ltd. owns scaffolding materials for about 100 single-family homes and plans according to the site, even in areas with slopes or elevation differences.

I’m in the middle of getting multiple estimates; can I just have a look at the estimate?

Of course, that’s possible. If you bring estimates from other companies, we will check for free whether the items, quantities, methods, and materials are appropriate and provide you with an estimate under the same conditions. We welcome multiple estimates.

Can I request just emergency repairs for a leak?

Yes. As a preliminary step before large-scale repairs, we also accept requests for emergency repairs or partial repairs for leaks. We will identify the cause using thermal imaging and drones and propose the minimum necessary repairs.

Can you handle roofing or exterior wall materials that contain asbestos?

Yes, we can. We have qualified personnel who are certified as asbestos work supervisors and building material surveyors for asbestos-containing materials. We handle everything from the legally mandated preliminary surveys to the roof overlay method and removal of asbestos-containing roofing materials. If there is sprayed asbestos, there is a possibility of receiving free surveys through Yokohama City’s countermeasure project and subsidies for two-thirds of the removal costs (up to 3 million yen), so we will provide information on that as well.

What happens if large-scale repairs are not done?

There are risks such as personal injury accidents due to falling exterior tiles, structural deterioration due to corrosion of rebar, leaks, and a decrease in asset value. Furthermore, for buildings subject to regular reporting under Article 12 of the Building Standards Act, investigations through full tapping and other methods are required under certain conditions, such as when the exterior wall has exceeded 10 years since completion or exterior wall renovation. In Yokohama City, buildings that are only apartment complexes are not designated as subject to regular reporting, but mixed-use buildings including stores require individual confirmation. Even if not subject to statutory surveys, regular inspections and maintenance are essential, so please consult us if you are unsure about your judgment.

How much does large-scale repair for an apartment (about 10 units) cost?

For a two-story wooden building with 6 to 10 units, the estimate is between 2 million and 4 million yen, and for a three-story steel or RC building with 10 to 20 units, it is between 4 million and 9 million yen based on our past performance (including scaffolding, substrate repairs, exterior wall painting, sealing, and waterproofing). It is common for apartments to undergo repairs every 10 to 15 years. For owners, there is an increasing trend to change the appearance through color simulations during repairs to improve occupancy rates.

If you are looking for a large-scale repair contractor in Naka Ward, Yokohama City, contact Kakeru Koumuten

Our company handles many exterior wall renovations and large-scale repairs for condominiums and apartments in Naka Ward, Yokohama City. We are happy to assist not only with large-scale repair work but also with partial repairs and leak repairs. “I want it to last long with one renovation” “I want to keep costs down as much as possible” “I want to improve insulation performance because the indoors are hot” We will propose the best solutions for your specific requests and future repair plans.

From temporary scaffolding work to roofing and exterior wall painting, all work is performed by our own team. We are confident that we will not lose in terms of cost, quality, and scheduling compared to other companies, so we welcome multiple estimates!

Large-Scale Repair Work Service Area

Kakeru Koumuten Co., Ltd. accepts requests throughout Kanagawa Prefecture and all of Tokyo.

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