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

Large-Scale Repairs for Condominiums, Apartments, and Buildings in Nishi Ward, Yokohama

Large-scale repair work that can be handled in Nishi 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 a free on-site survey to confirm the items below, compile them into a deterioration diagnosis report with photos, and propose the scope of work.

Reasons Why Kakeru Koumuten is Chosen for Large-Scale Repairs in Nishi Ward, Yokohama

The reason why we can be entrusted with large-scale repairs in Nishi Ward is partly because “Kakeru Koumuten has a base in Yokohama City”, but also due to our “unique 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 Scaffolding Materials

We own the scaffolding materials necessary for temporary scaffolding required for large-scale repairs and can assemble the scaffolding ourselves.
By performing scaffolding work with our own scaffolding team instead of outsourcing, we can cut costs for scaffolding work and provide quick and flexible responses.
We have approximately enough scaffolding materials for 100 single-family homes!

Material Storage 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 provide swift responses in emergencies!

In-House Waste Separation

During large-scale repairs, various waste materials such as leftover 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. Color simulations for exterior wall painting and heat resistance tests using a heat resistance testing machine are also available!

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, we can keep costs down while providing high-quality large-scale repairs. Additionally, one representative will handle everything from the estimate to project completion. Since the person in charge does not change, 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 national qualified 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 handle asbestos-containing roofing materials and conduct preliminary surveys.

4. Warranty and Aftercare

Most large-scale repair works, including “painting work,” “substrate repair work,” and “waterproofing work,” come with a warranty!
Aftercare maintenance is available every year, and we send out notification DM annually.

5. Flexible and Prompt Response

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

We can also address exterior walls and rooftops that cannot be checked from high places using drones! For rain leak investigations, we can use a thermal imaging camera, which helps identify the cause of leaks!

We will respond according to your wishes. We also accept emergency measures for sudden leaks! We will promptly respond 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 regularly provide skill enhancement education so that each staff member can respond effectively. We also educate on points to be careful of and areas to check in each process 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 we will also install a bulletin board at the entrance to display the construction schedule and notices! Additionally, we will thoroughly educate visitors on proper manners to minimize any 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 use film thickness inspection machines and check sheets to ensure that there are no oversights in the inspections. 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 prevent construction defects by ordering paint directly from our company. 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 applying a two-tone color or changing the image, 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 Nishi Ward, there are areas where building agreements and district plans are established, and the color of the exterior walls may need to harmonize with the surroundings. Having a color simulation screen will make explanations at community associations and general meetings proceed smoothly.

9-2 Confirm the Actual Color with a Test Paint!

You can order samples of the paint you are considering and perform a test paint on your exterior wall. By conducting a test 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 when metal siding is applied
・Simulation for when accent materials such as cornices and louvers are used
・Simulation for roof painting and roof replacement work

With the exterior renovation simulation, you can minimize the risk of failure in changing the image! We hope that renovating the appearance of apartments and condominiums will help increase occupancy rates.

Cost Estimates for Large-Scale Repairs in Nishi Ward, Yokohama

The cost of large-scale 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 cost estimates based on construction performance by scale, and finally to unit price examples 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 aggregated 818 construction cases (FY 2021), approximately 70% of the costs for large-scale 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. 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 Reserve Funds” *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 (What the Money is Spent On)

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 it includes equipment-related work, exterior works, and others. This is an average value and 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, metal work, plumbing, etc. For apartments, please also consider the amount calculated by multiplying the national statistics above (750,000 – 1,500,000 JPY per unit) by the number of units as a reference.

Breakdown of Costs for Temporary Work, Substrate Repair, Exterior, and Waterproofing

The estimate for large-scale repairs is broadly divided into “Temporary Work,” “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.

Unit Price Examples 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 of charge.

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, minimizing waste.

*The estimated lifespan is a general guideline and may vary depending on sunlight, location, and substrate condition. The rate of deterioration differs for each side based on location, sunlight exposure, and ventilation, so it is advisable to check the condition of each side through a site survey and select paint suitable for the location to enhance durability.

Guideline 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. An additional charge is required if there is a mechanical parking lot.

Source: Ministry of Land, Infrastructure, Transport and Tourism “Guidelines for 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 there is a shortfall.

Subsidies, Tax Systems, and Loans to Confirm for Large-Scale Renovations in Nishi 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 divided into the following four types. The eligibility and application status of the systems may change even during the fiscal year, so please be sure to check with our company or the relevant offices before contracting or starting work.（As of October 8, 2026）

① Condominium Longevity Promotion Tax System (Property Tax Reduction)

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 property tax for the building for the following year will be reduced by half (up to the equivalent of 100㎡ per unit; urban planning tax is not included).

* The national leaflet shows the range of reduction rates as a nationwide system. The reduction rate for Yokohama City is 50%.

② Yokohama City’s Condominium Management Support (For Management Associations, Start Here)

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

Source: Yokohama City “Support and Subsidy System List by Condominium Management Association Issues”／Long-term Repair Plan Creation Promotion Model Project／Condominium Advisor Dispatch／Yokohama Condominium Portal

③ Management Plan Certification System (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, 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, improving management regulations, separate accounting for management fees and repair reserves, overdue amounts within 10% of the total, and “having created or reviewed a long-term repair plan that includes large-scale repair work twice or more over a period of 30 years or more within 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 Conservation Support | Housing Energy Conservation 2026 Campaign

Changes for 2026The “Child-Rearing Green Housing Support Project” for 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 Reiwa 7, and will not be implemented in Reiwa 8. Please be careful not to base your financial plans on outdated information.

Mirai Eco Housing 2026 Project

Advanced Window Renovation 2026 Project

⑤ Kanagawa Prefecture Subsidies (Applications for the 2026 fiscal year 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 Financing System (Housing Finance Agency Condominium Sumairu Loan)

When a 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 Nishi Ward, Yokohama City

Nishi Ward, Yokohama City, became an independent ward in April 1944, following Minami Ward. According to ward documents, the “existing urban area” that retains the history and downtown atmosphere since the port’s opening coexists with the “city center” areas around Yokohama Station and Minato Mirai 21. The area is 7.03 km², ranking 18th out of 18 wards in size, while the number of employees in business establishments is 218,022, ranking 1st among the 18 wards (as of June 1, 2021). The district features neighborhoods that have been inhabited since before the war, land that has been reclaimed along with railways and ports, and planned neighborhoods that began development in fiscal year 1983, resulting in varying degrees of building wear and scaffolding methods depending on the location.

Source: Yokohama City “Population News” as of December 1, Reiwa 7 (Estimated)／Yokohama City Nishi Ward “Overview of Nishi Ward – Population and Characteristics” (Aging Rate, Area, Business Establishments)／Yokohama City “Data on Greenery” (Reiwa 1 Fiscal Year)／Yokohama City “List of District Plans”／Yokohama City “Building Agreements (Nishi Ward)”

Buildings in Nishi Ward are divided into “four types”

In Nishi Ward, the development of the town varies by location, so not only the age of the building but also the location of the building (Minato Mirai 21 area, urban center around Yokohama Station, established urban area since the opening of the port, residential areas with hills and elevated land) will affect the nature of the major repairs required in the next large-scale renovation. Please check which type your building falls under.

Source: Yokohama City Nishi Ward “Overview of Nishi Ward – Population and Characteristics” / Same “Do You Know? The History of Nishi Ward”・“Welcome to Nishi Ward” / Yokohama City “Minato Mirai 21 District Project Overview” / Yokohama City “District Planning” List

Four Factors Unique to Nishi Ward That Damage Buildings

Among the characteristics of Nishi Ward visible from Yokohama City’s public documents, we have organized four factors that are linked to large-scale repairs.

Source: Yokohama City Nishi Ward “Do You Know? The History of Nishi Ward” / Yokohama City “Flood Hazard Map (Nishi Ward Version)” / Yokohama City Nishi Ward “Overview of Nishi Ward – Population and Characteristics” / Yokohama City “Data on Greenery” / Yokohama City “List of District Plans”・“Minato Mirai 21 Central District” / Yokohama City “Building Agreement (Nishi Ward)” / Ministry of Land, Infrastructure, Transport and Tourism “2023 Comprehensive Survey on Condominiums” (PDF)

Key Points to Consider When Proceeding with Construction in Nishi Ward

*Kakeru Koumuten has five bases within Yokohama City and serves the entire Nishi Ward, including areas such as Yokohama, Minato Mirai, Sakuragicho, Takashima, Tobe, Hiranuma, Asama-cho, Fujidana-cho, Okano, and Kubo-cho.

Deterioration Symptoms and Timing That Require Major Repairs

Generally, large-scale repairs are recommended every 12 to 15 years. According to a survey by the Ministry of Land, Infrastructure, Transport and Tourism, 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 judgment should be based on the condition of deterioration rather than just the number of years, so if you observe any of the symptoms listed below, we recommend an early on-site inspection.

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 an example 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 wall and waterproofing for the rooftop.

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

Customer Feedback

Flow 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 starting the process 1 to 1.5 years before the desired start date allows for a smoother progression.

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 an exterior wall inspection, check for cracks, sealing, and waterproofing layers, and if necessary, investigate the roof, high places, and leak areas using drones or thermal imaging. For properties in Nishi Ward, we will also check the location, elevation differences, road width and delivery routes, pedestrian flow, drainage, parking, and distance to neighboring properties.
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 possible.
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 district planning and building agreements, we will also explain the considerations for color choices.
5. Notification to Residents & Neighbors We will distribute construction notifications, 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. Temporary Scaffold Installation & Various Works Our in-house scaffold team will set up scaffolding, followed by high-pressure washing, substrate repair, sealing, exterior wall painting, tile repair, waterproofing, and work on metal parts and accessories in that order. A responsible person will inspect each process and take construction photos.
7. Completion Inspection, Scaffold Dismantling & Handover We will confirm the finished work 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 annual DM notifications, and inspections can be conducted every year. Simple repairs such as partial sealing are provided free of charge.

Resident Communication, Additional Work Approval, Inspection Reports

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

* 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 restrictions on daily life while scaffolding is in place. Most troubles can be prevented by informing you in advance, so at Kakeru Koumuten Co., Ltd., we thoroughly explain and post notices before construction begins.

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

There are many large-scale repair contractors that cover Nishi Ward, 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 project achievements. If they provide detailed explanations of repair contents with photos, it gives you peace of mind as a reference when you actually request work.

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 project 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, be sure to check for warranties. 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! Companies that offer warranty periods demonstrate confidence in their work, making it a key 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 offer aftercare services separate from warranties, so be sure to check for warranties 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 responses 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, and warranties and aftercare services may differ as well. 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 repair 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 methods are suitable for the condition of the substrate!

Check These Points on the Estimate (Checklist)

Check if 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 will change based on the actual state of deterioration and customer preferences.

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

Moreover, contractors that outsource may also have delayed responses in case of any troubles during construction. It is safer to avoid companies that do not meet with customers directly to manage the construction. Kakeru Koumuten performs everything from temporary scaffolding installation 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 Inappropriate Consulting Issues in Large-Scale Renovations and Self-Defense Measures

Latest 2026 In the large-scale renovation industry, inappropriate orders linked between design consultants and construction companies have long been a concern. 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 a total of 1.63788 billion yen in payment orders to 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).

※Based on the announcement by the Japan Fair Trade Commission (September 28, 2026).

Three Typical Methods

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 specialists or architects
• Document the contractor selection process in meeting minutes to ensure transparency
• Confirm the reasons for unusually low consulting fees
• Include a penalty clause in the contract for cases of collusion
• 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 general competitive bidding. The estimated price will not be disclosed and will be conducted in a manner similar to public works.

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

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

How much does large-scale repair in Nishi 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 within the range of 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 company’s construction records, the cost for a two-story wooden apartment 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-scale 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 determining factor should be the condition of the building 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. Older buildings tend to have a greater proportion of tile repairs and steel part replacements during the second and third repairs.

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

The estimated construction period is about 3 weeks to 2 months for apartments, 1.5 to 3 months for small-scale apartments and buildings, and about 4 to 6 months for apartments with more than 50 units. 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 advance notices, providing information on the construction schedule and laundry through bulletin boards, and strictly adhering to working hours.

How long should I expect the entire process from planning to completion to take?

For management associations, the process from establishing a repair committee, conducting building diagnostics, selecting contractors, to passing resolutions at general meetings typically takes about 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 required to obtain management plan certification (2 to 3 months from application to certification).

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

Neither Yokohama City nor Kanagawa Prefecture offers subsidies specifically for large-scale repair work. However, for condominium owners, if certain conditions are met, there are options such as a 50% reduction in fixed property tax under the “Condominium Longevity Promotion Tax System,” subsidies from Yokohama City for deterioration diagnosis and long-term repair planning (50% up to 200,000 yen), and subsidies for making common areas barrier-free (1/3 up to 300,000 yen). If the work includes windows and insulation, it may qualify for “Advanced Window Renovation 2026” or “Mirai Eco Housing 2026.” The timing and applicants for each system vary, so please check the eligibility conditions and application procedures for each system before contracting or starting work.

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

Yes, it is true if the conditions are met. Under the Condominium Longevity Promotion Tax System, if a condominium that meets the 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 will be reduced by half for up to 100 square meters per unit. This applies to work completed between April 1, 2023, and March 31, 2027, and a declaration must be made to the Nishi Ward Office within three months of completion. For certified management plan condominiums, there are additional requirements such as raising the repair reserve fund, so it is recommended to start preparations more than a year in advance.

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

Yes, there are. The national “Child-Rearing Green Housing Support Project” has been abolished and reorganized into the successor “Mirai 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 started accepting bulk applications for apartment buildings from May 29, 2026 (application procedures will be handled by registered contractors). Please be careful not to base your financial planning 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 loan 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 you handle large-scale repairs for properties with many buildings, like in a housing complex?

You can consult us. According to the official page of Nishi Ward, it is said to be a district where the established urban area since the opening of the port coexists with the city center, such as around Yokohama Station and the Minato Mirai 21 area. For properties with many buildings, it is important to conduct deterioration diagnosis for each building, plan whether to carry out all buildings together or separate by building or year, and form consensus at the general meeting. Kakeru Koumuten Co., Ltd. also targets condominiums with over 100 units for cost estimates and will propose multiple plans for comparison.

What happens to the residents’ parking during construction?

Vehicles on the side where scaffolding is to be erected will need to be temporarily moved. In buildings with limited parking space, it may take time to secure a relocation spot. Kakeru Koumuten Co., Ltd. will coordinate with you about the availability of nearby coin parking and monthly parking starting 2 to 3 months before construction begins.

Can I freely decide the color of the exterior walls?

In Nishi Ward, there are three district plans (Minato Mirai 21 Central District, Yokohama Station West Exit and Tsuruyamachi District, and Yokohama Station South East Exit District) and one building agreement (Nissho Iwai, Toshiba, Mitsuzawa Housing District) listed by Yokohama City. The existence and content of agreements and plans regarding appearance and color vary by agreement and plan; for example, the district plan for Minato Mirai 21 Central District stipulates that consideration should be given to the harmony of colors throughout the district. You can check what applies to your property through the public information of Yokohama City’s building agreements and district plans, and the Yokohama City Urban Development Bureau’s Community Development Division (045-671-2667) also provides information on district plans. We will also investigate this during our survey. Sharing a color simulation to visualize the completed image can facilitate discussions with neighbors and community associations.

Are there differences in construction depending on the location, such as in Minato Mirai, around Yokohama Station, or in hilly residential areas?

Nishi Ward’s materials indicate that it is a district where the established urban area since the opening of the port coexists with the city center, such as around Yokohama Station and the Minato Mirai 21 area. Depending on the location, differences in slopes, elevation differences of the site, road widths, pedestrian traffic, and building sizes may require ingenuity in setting up scaffolding and transporting materials. Kakeru Koumuten Co., Ltd. has its own scaffolding team that checks the site and plans the transport route and scaffolding layout. Additionally, Yokohama City has published a flood hazard map (flood, internal water, storm surge) for Nishi Ward, so we also focus on inspecting roof drains, drainage areas, and waterproof layer damage in preparation for heavy rain. The degree of deterioration varies by building, so we conduct individual diagnoses during on-site surveys.

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

For buildings with fewer units, the burden of consulting fees tends to be heavier, so we believe that the responsibility construction method is often more 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; however, consulting fees are incurred separately, and attention must be paid to the risks of conflicts of interest and collusion. 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 them 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 affiliated contractors, ③ Adding a portion of the contract amount as a back margin to the construction costs. Countermeasures include obtaining independent estimates, consulting a neutral third party, documenting the selection process in meeting minutes, and including penalty clauses in contracts. In October 2025, Yokohama City and the Yokohama City Housing Supply Corporation will establish a “Large-Scale Repair Construction Bidding Agency Service.”

How many companies should I get estimates from?

We recommend at least three companies. If there are too many, it becomes difficult to compare, and if there are too few, competition does not occur. 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, while 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 approximately 100 single-family homes and plans scaffolding on-site according to the site conditions.

Can I just have the estimate reviewed while I am in the process of getting multiple estimates?

Of course, that is 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 inspectors for asbestos-containing materials. We handle everything from the legally required 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 this as well.

What happens if large-scale repairs are not done?

There are risks such as personal accidents due to falling exterior wall tiles, structural deterioration due to corrosion of rebar, leaks, and decreased asset value. Furthermore, for buildings subject to periodic 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 been completed or renovated for more than 10 years. In Yokohama City, buildings that are only residential apartments are not designated as subject to periodic reporting, but mixed-use buildings that include stores require individual confirmation. Even if not subject to statutory inspections, regular inspections and maintenance are essential, so please consult us if you are unsure.

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

For wooden two-story buildings with 6 to 10 units, it is estimated to be between 2 million and 4 million yen, and for three-story steel or RC buildings with 10 to 20 units, it is estimated to be between 4 million and 9 million yen based on our company’s track record (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 exterior appearance using color simulations during repairs to improve occupancy rates.

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

Our company is based in Yokohama City and has handled many exterior wall renovations and large-scale repairs for condominiums and apartments in Nishi Ward. We are happy to assist not only with large-scale repair work but also with partial repairs and leak repairs. In urgent cases such as leaks, emergency measures may be possible, so please feel free to consult us. “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 room is 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 be outdone 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 Tokyo.

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