Large-Scale Renovation in Aoba, Yokohama City | For Repairs and Renovations of Condominiums and Apartments, Contact Kakeru Koumuten Co., Ltd.

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

Large-scale repair work that can be handled in Aoba 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. Kakeru Koumuten 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 always necessary to carry out all of 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 following and compile a deterioration diagnosis report with photos, after which we will propose the scope of work.

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

The reason why we can be entrusted with large-scale repairs in Aoba Ward is partly because “Kakeru Koumuten has a base in Aoba Ward”, 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 Ownership of Scaffolding Materials

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

Storage of Materials in Our Large In-house Warehouse

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

In-house Sorting of Waste Materials

In large-scale repairs, various waste materials such as waste paint, metals, 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 the showroom, you can not only have meetings but also check actual samples and colors of exterior materials. You can also perform color simulations for exterior wall painting and check 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.

From inquiry to project completion, everything is managed by Kakeru Koumuten in a consistent system, allowing for high-quality large-scale repairs at reduced costs. 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. Various Permits and Skilled Workers

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

4. Warranty and Aftercare

Most large-scale repair work, including “painting work,” “substrate repair work,” and “waterproofing work,” comes with a warranty!
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 inspected from high places using drones! During leak investigations, we can use a thermal imaging camera to help identify the cause of leaks!

We will respond according to your wishes. We also accept emergency measures for sudden leaks! We will promptly 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 to ensure each staff member can respond effectively. We also educate on points to be careful about and areas to check during 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 entrants on manners to minimize inconvenience to residents and neighbors.

8. Strict Quality Control

Inspections and detailed construction photos will be taken by responsible personnel for each process. We use film thickness inspection machines and check sheets to ensure that there are no inspection omissions. During exterior wall painting and waterproofing work, we check the quantity of used paint cans to confirm that the specified amount of paint is being used, and we order paint in-house to prevent construction defects. 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!Simulations can also be done on your smartphone or computer. By simulating before changing to a two-tone color or making an image change, we hope to enhance the stylish appearance and contribute to an increase in occupancy rates! Of course, we can also arrange paint samples for actual color confirmation.

* Aoba Ward has many areas where “colors in harmony with the surrounding landscape” are required by building agreements and district plans. Having a color simulation screen will help facilitate explanations at neighborhood associations, agreement management committees, and general meetings.

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

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

9-3 Exterior Renovation Simulation

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

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

Cost Estimate for Large-Scale Repairs in Aoba Ward, Yokohama City

The cost of large-scale repairs varies significantly 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 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.” Please note that the amounts in this survey do not include consumption tax and common temporary construction costs, so the conditions differ from the current total construction cost 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 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 work 22.3%, miscellaneous expenses 9.9%). *The total does not equal 100% because equipment-related work, exterior works, and others are included. This is an average value and should not be used as a standard for judging the appropriateness of individual estimates.

Estimated Costs by Building Size (Scaffolding, Substrate Repair, Exterior Painting, Waterproofing, Sealing)

*The above is an estimate based on Kakeru Koumuten’s past performance 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 (750,000 – 1,500,000 JPY per unit) by the number of units.

Breakdown of Costs for Scaffolding, Substrate Repair, Exterior Walls, 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 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 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 shaded and humid areas like Aoba Ward, choosing paint with anti-algae and anti-mold properties can improve durability.

Guidelines for Repair Reserve Funds and Options When Insufficient

According to the Ministry of Land, Infrastructure, Transport and Tourism guidelines, the guideline for repair reserve funds is indicated as a monthly amount per exclusive area. Additional charges are 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 Check for Large-Scale Renovations in Aoba 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 categorized into the following four types. The eligibility and application status of these systems may change even during the fiscal year, so be sure to confirm with our company or each contact point before signing a contract or starting work. (As of October 5, 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 condominiums meeting certain requirements are carried out, the property tax amount for the following year will be reduced by half (up to 100㎡ per unit; urban planning tax is not included).

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

The support system in Yokohama City is mostly based on the premise 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. Upon certification, you can receive a 0.2% reduction in the loan interest rate from the Japan Housing Finance Agency, preferential interest rates for Flat 35, and meet one of the requirements for the Long-term Durability Promotion Tax System (certification alone does not guarantee tax reduction). The main criteria include holding general meetings at least once a year, maintaining management regulations, separate accounting for management fees and repair reserves, ensuring that arrears are within 10% of the total, and “having created or reviewed a long-term repair plan that includes two or more large-scale repair works over a period of 30 years or more within the last 7 years.”

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

④ National Energy Conservation Support | Housing Energy Conservation 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 Excellent Housing Renovation Promotion Project” will end in FY 2027 and will not be implemented in FY 2028. 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 Fiscal 2026 have ended)

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

⑥ Financing System (Housing Finance Agency Condominium Sumairu Loan)

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

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

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

Building conditions and repair points in Aoba Ward, Yokohama City

Aoba Ward, Yokohama City, was developed as a residential area planned as part of the Tama Den-en-toshi, triggered by the opening of the Tokyu Den-en-toshi Line between Mizonokuchi and Nagatsuta in 1966 (Showa 41). About 90% of the residential areas in the ward have been urbanized through planned development such as land readjustment, resulting in the characteristic that “collective housing built around the same time reaches the repair period at the same time.”

Source: Yokohama City Aoba Ward “Naruhodo Aoba” / Yokohama City “Data on Greenery” (FY 2019) / Yokohama City Aoba Ward Plan / Yokohama City Housing Policy Council Condominium Subcommittee Materials

Collective housing in Aoba Ward is divided into “four generations”

In Aoba Ward, the history of development is reflected in the layers of building age. The type of major repairs that will be needed next will vary depending on which layer your building falls into.

Four Factors Unique to Aoba Ward That Damage Buildings

It is sometimes explained that “Yokohama City needs measures against salt damage,” but inland Aoba Ward has other factors to be cautious about besides salt damage. While investigating buildings in Aoba Ward, I repeatedly encounter the following four factors.

Source: Yokohama City “Data on Greenery” / Yokohama City “Large-Scale Landfill Areas” / Yokohama City “District Plans”・“Building Agreements (Aoba Ward)”

Key Points to Consider When Advancing Construction in Aoba Ward

* Kakeru Koumuten has a base that includes a showroom and material storage in Aoba Ward, allowing us to promptly visit all areas of Aoba Ward, including Aobadai, Azamino, Tama-Plaza, Ichigao, Fujigaoka, Eda, and Tana.

Signs of Deterioration Requiring Major Repairs and Timing

Generally, major repairs are estimated to occur 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 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 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 from several locations, and we combined clear waterproofing for the tile exterior wall with waterproofing for the rooftop for the renovation.

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 tapping survey, check for cracks, sealing, and waterproofing layers, and if necessary, investigate the roof, high places, and leak areas using drones or thermography. For properties in Aoba Ward, we will also check the condition of retaining walls, slopes, trees, as well as the delivery route and parking.
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 boards, 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 selection.
5. Notification to Residents & Neighbors We will distribute construction notifications, 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 in-house scaffold team will set up the scaffolding, followed by high-pressure washing → substrate repair → sealing → exterior wall painting & tile repair → waterproofing → iron parts & ancillary work in that order. A supervisor will inspect and take construction photos at 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

Just as 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 restrictions on 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 work begins.

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

There are many large-scale repair contractors that cover Aoba Ward in 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 can give 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 potential 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, let’s confirm the presence of a warranty. 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 a warranty demonstrate confidence in their work, making it a key criterion for selecting a contractor.

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

Kakeru Koumuten Co., Ltd. sends out annual direct mail for aftercare maintenance, allowing for yearly inspections. We also offer free support for simple repairs such as partial sealing.

Obtain Estimates from Multiple Contractors (at least 3)

When requesting large-scale repairs, obtain estimates from multiple contractors. It is important to get estimates from at least 3 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” 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 This on the Estimate (Checklist)

Confirm if managed in-house

Large-scale repair works involve 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 may lack knowledge and experience, leading to proposals for repairs in the wrong areas or unnecessary work. If you request a subcontractor after investigation, it may incur additional time and costs. By having knowledge and experience and managing in-house, responsible construction at reduced costs becomes possible.

Additionally, contractors that outsource may respond slowly in case of any troubles during construction. It is safer to avoid companies that do not have direct meetings with customers managing the construction. Kakeru Koumuten performs everything from temporary scaffolding 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 as follows:

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

Latest 2026 In the large-scale renovation industry, improper orders linked between design consultants and construction companies have long been a problem. The Ministry of Land, Infrastructure, Transport and Tourism issued warnings and notifications to management associations in January 2017 and April 2023, and on September 28, 2026, the Japan Fair Trade Commission announced that it had issued exclusion orders to 38 companies and 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 professionals or architects
• Document the vendor 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 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 Aoba Ward, Yokohama

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

For condominiums, according to the Ministry of Land, Infrastructure, Transport and Tourism’s survey for the fiscal year 2021, about 70% fall within the range of 750,000 to 1,500,000 yen (excluding consumption tax and common temporary construction costs), with the most common 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, 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 condominiums 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 and roofing work are required, 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’s survey, with about 70% falling within 12 to 15 years. 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 better to repair without waiting for the cycle, as this can ultimately reduce costs. In Aoba Ward, where many buildings are 30 to 50 years old, there tends to be a greater focus on tile repairs and metal part replacements during the second and third repairs.

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

For apartments, the construction period is typically 3 weeks to 2 months, for small condominiums or buildings 1.5 to 3 months, and for condominiums with over 50 units about 4 to 6 months. Residents can remain in their homes during the construction. However, while scaffolding is up, 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 schedule and laundry through bulletin boards, and strictly adhering to working hours.

How long should I expect from the start of planning to the completion of 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 about 2 years to proceed comfortably. If you are using subsidies or tax incentives, please also factor in the time to obtain management plan certification (which takes 2 to 3 months from application to certification).

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

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

I heard that fixed asset tax can be reduced with 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 asset 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 Aoba Ward Office within three months of completion. For certified management plan condominiums, there are additional requirements such as raising repair reserve funds, so it is recommended to start preparations more than a year before the work.

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

Yes, there are. The national “Child-Rearing Green Housing Support Project” has been abolished and reorganized into the successor “Future Eco Housing 2026 Project.” Management associations and management corporations can also become joint project participants, allowing for insulation renovations in common areas. Additionally, the “Long-Term Excellent Housing Renovation Promotion Project” will end in fiscal year 2025, and it will not be implemented in fiscal year 2026. The “Advanced Window Renovation 2026 Project” began accepting bulk applications for apartment buildings starting 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?

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

Aoba Ward has many slopes, but can scaffolding be set up on top of retaining walls or on sloped land?

Yes, it can. Aoba Ward has an elevation difference of about 80m within the ward, and there are many buildings on retaining walls and terraced land. Kakeru Koumuten Co., Ltd. owns its own scaffolding materials and has its own scaffolding team, allowing us to plan support and layout of the boards after confirming the site. This is an area where additional costs can easily arise after seeing the site, so it is important to confirm the delivery route during the estimation stage. We also check the deterioration of retaining walls and slopes and consult on whether they are included in the long-term repair plan.

What will happen to the parking lot for residents during construction?

Vehicles on the side where scaffolding will be erected will need to be temporarily moved. Aoba Ward has a high number of passenger cars, and depending on the availability of nearby parking lots, it may take time to secure a relocation spot. Kakeru Koumuten Co., Ltd. will coordinate with you about 2 to 3 months before starting work, including checking the availability of nearby coin parking and monthly parking lots.

Can I freely decide the color of the exterior walls?

Aoba Ward has 42 building agreements and 12 district plans, and in many areas, it is stipulated that “the colors of roofs and exterior walls should harmonize with the surrounding landscape.” Since this is not a numerical standard, the key point is to form consensus with neighbors, community associations, and the agreement management committee. Sharing a color simulation to visualize the completed image can facilitate discussions. You can check what regulations apply to your property at the Aoba Ward Community Rule-Making Consultation Center (045-978-2217). We will also investigate this during our survey.

Why is the north-facing exterior wall so badly affected by moss and algae?

Aoba Ward has a green coverage rate of 28.8% (as of the 2019 survey), creating a living environment with greenery, which makes it easy for areas to be shaded by street trees and neighboring trees. When insufficient sunlight and humidity overlap, moss, algae, and mold can proliferate. By thoroughly removing them with high-pressure washing and choosing paint with anti-algae and anti-mold properties, recurrence can be suppressed. We also recommend checking for blockages in roof drains and gutters caused by fallen leaves, as these often lead to puddles on the roof and leaks.

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

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

How can I detect collusion in large-scale repairs?

There are three typical tactics. 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, 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 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 Bid 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 “to compare after creating the same conditions.” By creating a common specification sheet and quantity table and requesting under the same conditions, and making detailed breakdowns mandatory instead of allowing “one set” notation, it becomes clear whether the price difference is due to differences in range or unit prices.

What is the difference if you own your own scaffolding?

Among the costs of large-scale repair work, temporary construction accounts for about 20% (according to the Ministry of Land, Infrastructure, Transport and Tourism’s fiscal year 2021 survey). By not outsourcing scaffold work, we can easily keep costs down in this area, and our in-house scaffold team can flexibly respond to sudden changes in the schedule or additional work. Kakeru Koumuten Co., Ltd. owns scaffold materials for approximately 100 detached houses and plans according to the site conditions, even in areas with elevation differences like Aoba Ward.

Can I just have a look at the estimate while I’m comparing quotes?

Of course, that’s possible. If you bring in 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 comparative 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 for leaks or partial repairs. 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 such as asbestos work supervisors and building material asbestos surveyors, and we 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 and subsidies covering two-thirds of the removal costs (up to 3 million yen) through Yokohama City’s countermeasures project, so we will provide information on that as well.

What happens if I don’t carry out large-scale repairs?

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 regular reporting under Article 12 of the Building Standards Act, an investigation through full tapping and other methods is required under certain conditions, such as when more than 10 years have passed since completion or exterior wall renovations for tile or mortar-finished walls. In Yokohama City, buildings that are only apartment complexes are not designated as subject to regular reporting, but mixed-use buildings including stores require individual confirmation. Even if not subject to statutory investigations, 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 a wooden two-story building with 6 to 10 units, the estimate is around 2 million to 4 million yen, and for a three-story steel or RC building with 10 to 20 units, it is around 4 million to 9 million yen based on our past performance (including scaffolding, substrate repairs, exterior wall painting, sealing, and waterproofing). It is common for apartments to undergo repairs every 10 to 15 years. For owners, there is an increasing trend to change the appearance with color simulations during repairs to improve occupancy rates.

If you’re looking for a large-scale repair contractor in Aoba Ward, Yokohama, contact Kakeru Koumuten

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

From temporary scaffold work to roofing and exterior wall painting, all work is performed by our own team. We are confident that we will not be outdone by others in terms of cost, quality, and organization, so we welcome comparative estimates!

Areas Covered for Large-Scale Repair Work

Kakeru Koumuten accepts requests throughout Kanagawa Prefecture and Tokyo Metropolis.

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