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

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

Large-scale repair work that can be handled in Konan 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 from Building Diagnosis

It is not always necessary to carry out all the above works. 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 Kakeru Koumuten is Chosen for Large-Scale Renovations in Konan Ward, Yokohama City

The reason why we can be entrusted with large-scale repairs in Konan 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 replicated 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 our material storage and showroom.

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 not outsourcing scaffolding work and using our own scaffolding team, we can cut costs on scaffolding work and provide quick and flexible responses.
We own enough scaffolding materials for approximately 100 single-family homes!

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, allowing us to provide swift responses in emergencies!

In-house Waste Sorting

In 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, which helps reduce waste disposal costs.

Showroom Dedicated to Exterior Renovations

In our 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 heat insulation properties using a heat 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 inquiry to project completion in a consistent 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, communication can proceed smoothly.

We can fully handle everything from temporary scaffolding installation to exterior wall painting, substrate repair, waterproofing work, and tile repairs with our own team! 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 industry licenses and permits for industrial waste collection and transportation! We also have national certified sheet metal and painting skilled workers on staff, 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 almost all types of work, 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 related to apartments and condominiums.

We can also address exterior walls and rooftops that cannot be checked from high places using drones! During rain 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 rain leaks! We will promptly respond to urgent requests or emergencies!

6. Staff Development

Our staff create various models for skill enhancement and conduct practical training. Since different sites require various processing and techniques, we regularly provide skill improvement education to ensure each staff member can respond appropriately. We also educate on points to be careful about and areas to check in 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 proper manners to minimize any inconvenience to residents and neighbors.

8. Thorough Quality Control

Each process will be inspected by a responsible person, and detailed construction photos will be taken. We will 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 quantity of used paint cans to confirm that the specified amount of paint is being used, and we will 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

The simulations we create can be done using actual photos of your apartment or building!You can also perform the simulation 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 increase the occupancy rate! Of course, we can also arrange paint samples for actual color confirmation.

* In Konan 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 meetings and general meetings proceed smoothly.

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

You can order samples of the paint you are considering and perform a sample paint application on your exterior wall. By conducting a sample 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 image changes! We hope that renovating the appearance of your apartment or condominium will help increase occupancy rates.

Estimated Costs for Major Repairs in Konan Ward, Yokohama City

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

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), the construction costs for major repairs are concentrated at about 70% 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 (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 is not a criterion for judging the appropriateness of individual estimates.

Estimated Costs 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 above (750,000 – 1,500,000 JPY per unit) by the number of units.

Breakdown of Costs for Scaffolding, Substrate Repair, Exterior, and Waterproofing

The estimate for large-scale repairs is broadly divided into “Scaffolding,” “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 based 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 to conduct the next major repair 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. In areas with many slopes, or on sides with different sunlight and airflow, the rate of deterioration varies, so confirming the condition of each side through an on-site survey and selecting paint suitable for the location can change durability.

Guideline for Repair Reserve Funds and Options When Insufficient

The Ministry of Land, Infrastructure, Transport and Tourism guidelines indicate the guideline for repair reserve funds as a monthly amount per exclusive area. Additional charges are required 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 there is a shortfall.

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

Both Yokohama City and Kanagawa Prefecture do not have subsidies specifically for large-scale renovation work. The available options can be broadly divided 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 confirm with our company or the respective offices before contracting or starting work. (As of October 7, 2026)

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

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

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

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

The support system in Yokohama City is mostly based on the requirement of registration in the “Yokohama City Apartment 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 / Yokohama Condominium Portal

③ Management Plan Certification System (Entrance to Tax and Interest Rate Benefits)

This is a system certified by Yokohama City. Once certified, you can receive a 0.2% reduction in loan interest rates from the Japan Housing Finance Agency, preferential interest rates for Flat 35, and meet 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 reserve funds, ensuring that the amount in arrears is within 10% of the total, and “having a long-term repair plan that includes large-scale repair work twice or more and is created or reviewed within 7 years with a planning period of 30 years or more.”

*Fees include a system usage fee of 10,000 yen + 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 FY 2026The “Child-Rearing Green Housing Support Project” for FY 2025 has been abolished and reorganized into the successor “Mirai Eco Housing 2026 Project.” Additionally, the “Long-Term Quality Housing Renovation Promotion Project” will end in FY 2027 and will not be implemented in FY 2028. 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 Financing System (Housing Finance Agency Condominium Sumairu Loan)

If the management association borrows funds for large-scale repairs, it 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 Konan Ward, Yokohama City

Konan Ward, Yokohama City, was established on October 1, 1969, when it was separated from Minami Ward during administrative reorganization. According to ward materials, it is characterized by an undulating terrain consisting of lowlands in the Ooka River and Kashio River basins and plateaus extending from the Tama Hills. The opening of the Keikyu Main Line and Kamiooka Station in 1930 accelerated development along the line, and from around 1960, residential development and urbanization accelerated. It is also notable for having many town names derived from valleys and hollows, such as Okubo, Kamiyagata, and Serigaya. Depending on the location, the way buildings deteriorate and the method of scaffolding can vary.

Source: Yokohama City Konan Ward “Ward Administration Data Book (Population, Households, Area)”／Yokohama City “Data on Greenery” (Reiwa 1)／Yokohama City “Building Agreement (Konan Ward)”／Yokohama City Konan Ward “Origin of Town Names”

Buildings in Konan Ward are divided into “four types”

In Konan Ward, due to the different development histories of the areas, not only the age of the buildings but also the location of the buildings (flat land, residential areas developed for housing, housing complexes, and areas around stations) 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 Konan Ward “Formation of Konan Ward and Origin of Town Names”／Same “Konandai”／Yokohama City “District Plan for the Area Around Konan Chuo Station”

Four Factors Unique to Konan Ward That Damage Buildings

We have organized four characteristics of Konan Ward visible from Yokohama City’s public documents that are linked to large-scale repairs.

Source: Yokohama City Konan Ward “Hazard Map” / Yokohama City “Data on Greenery” / Yokohama City “Building Agreement (Konan Ward)”・“District Plan”・“Konan Nomura Konan-dai Area” / Ministry of Land, Infrastructure, Transport and Tourism “FY2023 Comprehensive Survey on Condominiums” (PDF)

Key Points to Consider When Proceeding with Construction in Konan Ward

*Kakeru Koumuten has five bases in Yokohama City and serves the entire Konan Ward, including Kamiooka, Konan-dai, Konan Chuo, Hino, Sasashita, Serigaya, and Shimonagaya.

Deterioration Symptoms and Timing Requiring Major Repairs

Generally, major repairs are estimated to occur in a 12 to 15-year cycle. 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 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 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 are set according to the building’s specifications, location conditions, and deterioration status.

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 we combined clear waterproofing for the tile exterior wall with waterproofing for the roof for the renovation.

Exterior Renovation Work on a Mixed-Use Building (Tile Exterior Wall Waterproofing + Roof 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 required, so it is advisable to start moving 1 to 1.5 years before the desired start time 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 an exterior wall inspection, check for cracks, sealing, and waterproofing layers, and if necessary, use drones or thermal imaging to investigate the roof, high places, and leak areas. For properties in Konan Ward, we will also check the slope and elevation differences of the site, retaining walls, drainage in valleys, access routes, parking, and distances to neighboring properties.
3. Investigation Report & Estimate Submission 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 or building agreements, we will also explain the considerations for color choices.
5. Notification to Residents & Neighbors We will distribute construction notices, conduct greetings to neighbors, 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 own scaffold team will set up the scaffolding, followed by high-pressure washing → substrate repair → sealing → exterior wall painting & tile repair → waterproofing → ironwork & ancillary work in that order. A supervisor will inspect and take construction photos for each stage.
7. Completion Inspection, Scaffold Dismantling & Handover We will confirm the finish in the presence of the customer and provide construction photos, a report on the paints 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, Additional Work Approval, 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 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 approximate amount that will require 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 on 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 the construction begins.

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

There are many large-scale repair contractors that cover the Konan 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 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 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 neighboring inhabitants. 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 Guarantees and Aftercare Services

When choosing a large-scale repair company, it is essential to confirm the availability of guarantees. If any issues such as leaks occur after the construction, having a leak guarantee from the contractor ensures that repairs can be made at no cost, providing peace of mind! Companies that offer a warranty period demonstrate confidence in their work, which can serve as a criterion for selecting a contractor.

The warranty period varies by contractor and the nature of the work, but it is generally set between 1 to 10 years. Emergency measures and partial repairs often do not come with a leak guarantee. Some contractors also provide aftercare services separate from the warranty, so it is important to check for guarantees 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 support for simple repairs such as partial sealing.

Obtain Estimates from Multiple Contractors (at least 3)

When requesting large-scale repairs, be sure to obtain estimates from multiple contractors. It is important to acquire estimates from at least three companies and compare their quotes and reports! Even for the same work, costs can vary between contractors, and guarantees and aftercare services may differ. 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” in detail! 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 visually, ensure that the repair method is appropriate 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 deterioration condition and customer preferences.

Contractors that completely outsource 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 outsource may also be slow to respond if any troubles occur during construction. It is safer to avoid companies that do not actually meet with customers to manage 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 as follows:

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 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
• 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 public competitive bidding. The estimated price will not be disclosed and 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 Konan Ward, Yokohama

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

For condominiums, 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 estimate is between 2,000,000 to 4,000,000 yen; for a three-story steel or RC apartment, it ranges from 4,000,000 to 9,000,000 yen; and for small condominiums or mixed-use buildings, it is between 5,000,000 to 15,000,000 yen. The cost varies depending on the condition of the substrate and whether waterproofing and roofing work are required, so we will provide an estimate through a free on-site survey.

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 there are signs of deterioration in sealing, tile lifting, or breaks in the waterproof layer, 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 in the second and third repairs.

What is the construction period? Can residents stay during the work?

For apartments, the period is approximately 3 weeks to 2 months; for small condominiums or buildings, it is about 1.5 to 3 months; and for condominiums with more than 50 units, it typically takes 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 notices before construction, providing information on the schedule and laundry through bulletin boards, and strictly adhering to work hours.

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

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

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

Neither Yokohama City nor Kanagawa Prefecture offers subsidies specifically for large-scale repair work. However, for condominium owners, if certain requirements are met, there are benefits 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 of applications and applicants varies by program, so please check the eligibility criteria and application procedures for each program before contracting or starting construction.

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

It is true if the requirements are met. Under the Condominium Longevity Promotion Tax System, if a condominium that is over 20 years old and has more than 10 units conducts large-scale repairs (including exterior painting, floor waterproofing, and roof waterproofing) that contribute to longevity, the fixed property tax for the following year can 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 Konan Ward Office within three months of completion. For certified management plan condominiums, there are additional requirements such as raising repair reserve funds, which can take time to prepare, so it is recommended to start planning more than a year in advance.

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 “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 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 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. In Konan Ward, there are many housing complexes named after birds, such as “Kamome Danchi” and “Hibari Danchi,” developed by the Japan Housing Corporation (according to the ward’s official page). For properties with many buildings, it is important to conduct deterioration diagnosis for each building, plan the process for whether to do it all together or separate by building or year, and form consensus at the general meeting. Kakeru Koumuten Co., Ltd. also targets cost estimates for condominiums with over 100 units and will propose multiple process plans for comparison.

What happens to the residents’ parking during construction?

Vehicles on the side where scaffolding is set up 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 Konan Ward, there are 10 building agreements listed by Yokohama City (Yokoho Daisugi Danchi, Hino Green Town, Hinocho Sawagaya, Yokohama Konandai, Hiyagiyama Residents’ Association Housing Area, Hino 9-chome, Atlas Kamiooka Garden, Konan Fujimidai, Park Hill Kamiooka, Common City Hino Housing Area), and district plans are established in areas such as Konan Shimonagaya Housing Area, Konan Hino Area, Kamiooka Nishi 1-chome Area, Konan Nomura Konandai Area, Konan Maruyama Area, Konan Chuo Station Area, Kamiooka C South Redevelopment Promotion Area, and Konan Tsutsujioka Area. The existence and content of agreements regarding appearance and color vary by agreement and plan; for example, the district plans for Konan Nomura Konandai Area and Konan Chuo Station Area have stipulations regarding form and design. You can check what applies to your property through the public information on Yokohama City’s building agreements and district plans, and the Konan Ward Office’s Urban Development Promotion Division (045-847-8319) also provides information on the ward’s town development. We will also investigate this during our survey. Sharing a color simulation of the completed image can facilitate discussions with neighbors and the residents’ association.

Are there any differences in scaffolding and construction for buildings located in hilly areas?

Konan Ward is described in the ward’s materials as having “flat land formed by mountains and hills, as well as the Ooka River and Hirado Nagaya River,” indicating a terrain with many undulations. For buildings with slopes, elevation differences, or retaining walls, special considerations may be needed for scaffolding installation and material delivery. Kakeru Koumuten Co., Ltd. has its own scaffolding team that will check the site and plan the delivery route and scaffolding layout. Additionally, we focus on inspecting the rooftop drains, drainage areas, escape routes around retaining walls, and any damage to the waterproof layer. The degree of deterioration varies by building, so we will conduct individual assessments during the on-site survey.

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, additional consulting fees are incurred, and caution is needed 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 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 partner companies, indicating collusion, ③ Adding a portion of the contract amount as a back margin to the construction costs. Countermeasures include obtaining independent estimates, consulting with neutral third parties, 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 Work 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 work. What is important is not the number of companies but “comparing after creating the same playing field.” 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 difference is due to differences in range or unit price.

What is the difference if we have our own scaffolding?

In large-scale repair work, 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, it is easier to 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 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 in estimates from other companies, we will check whether the items, quantities, methods, and materials are appropriate for free and provide 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 asbestos work supervisors and building material surveyors for asbestos-containing materials, and we can handle everything from the legally required preliminary surveys to the cover method and removal of asbestos-containing roofing materials. If there is sprayed asbestos, you may be eligible for free surveys under Yokohama City’s countermeasure project and receive up to two-thirds (maximum 3 million yen) of the construction costs for removal, etc., 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 wall tiles, structural deterioration due to corrosion of rebar, leaks, and a decrease in asset value. Furthermore, for buildings subject to periodic reporting under Article 12 of the Building Standards Act, investigations by full tapping and other methods are required under certain conditions, such as when more than 10 years have passed since completion or exterior wall renovations for tiles and mortar-finished walls. In Yokohama City, buildings that are only apartments are not designated as subject to periodic reporting, but mixed-use buildings including 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 about your judgment.

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

For wooden two-story buildings with 6 to 10 units, the estimate is around 2 million to 4 million yen, and for three-story steel or RC buildings with 10 to 20 units, it is around 4 million to 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 appearance with color simulations during repairs to improve occupancy rates.

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

Our company is based in Yokohama City and has undertaken many exterior wall renovations and large-scale repairs for condominiums and apartments in Konan Ward. We are happy to handle not only large-scale repair work but also 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 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 the entire Tokyo Metropolitan Area.

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