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

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

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

Large-scale repairs are not just “exterior wall painting” or “waterproofing,” but rather a project that addresses the overall deterioration of the building 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 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 items below, compile a deterioration diagnosis report with photos, and propose the scope of work.

Reasons Kakeru Koumuten is Chosen for Large-Scale Repairs in Seya Ward, Yokohama City

The reason our company is entrusted with large-scale repairs in Seya Ward is partly because “Kakeru Koumuten has a base in Yokohama City”, but also due to “our unique approach to large-scale repair work that cannot be imitated by other companies”, which has 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, allowing us to assemble scaffolding ourselves.
By not outsourcing scaffolding work and using our own scaffolding team, we can cut costs related to scaffolding work and respond quickly and flexibly.
We have approximately enough scaffolding materials for 100 single-family homes!

Storage of Materials in Our Large 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 for swift responses in emergencies!

In-house Waste Separation

Large-scale repairs generate various waste materials such as leftover paint, metal, and wood. At Kakeru Koumuten, we separate and recycle waste materials in-house, leading to cost reductions in waste disposal.

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 ensuring 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 conduct inspections and actual construction for each process!

3. Various Permits and Skilled Workers

We have obtained construction industry licenses and permits for industrial waste collection and transportation! We also have nationally 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 handle asbestos-containing roofing materials and pre-investigations as well.

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 annually, and we send out notification DM every 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 a drone! 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 and 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 effectively. We also educate on points to pay attention to 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 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 will use a film thickness inspection machine and check sheets to ensure that no inspections are overlooked. 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 we will prevent construction defects by ordering paint in-house. 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 applying a two-tone color or changing the image, we hope to enhance the stylish appearance and increase occupancy rates! Of course, we can also arrange paint samples for actual color confirmation.

* In Seya 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 can help facilitate explanations at neighborhood associations and general meetings.

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

You can order samples of the paint you are considering and conduct a test paint on your exterior wall. By performing 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 significantly reduce the risk of failure in image changes! We hope that renovating the appearance of apartments and condominiums will help increase occupancy rates.

Estimated Costs for Major Repairs in Seya Ward, Yokohama City

The cost of major repairs varies greatly depending on the size of the building, its deterioration status, 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 project.

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

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

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

Breakdown of Construction Costs (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 round of large-scale renovation work aggregation. Overall average is construction-related 59.0%, temporary construction 22.3%, miscellaneous expenses 9.9%). *The total does not equal 100% because equipment-related work, exterior works, and others are included. This is an average value and 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 Structures, Substrate Repair, Exterior Walls, and Waterproofing

The estimate for large-scale repairs is broadly divided into “Temporary Structures,” “Substrate Repair,” “Sealing,” “Exterior Painting,” “Waterproofing,” and “Miscellaneous Expenses.” Before comparing total amounts, please check what is included in each item, 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 always 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, and ventilation, so checking the condition of each side through a site survey and selecting paint suitable for the location can affect longevity.

Guidelines for Repair Reserve Funds and Options When Insufficient

The Ministry of Land, Infrastructure, Transport and Tourism guidelines indicate the estimated repair reserve fund on a monthly basis per exclusive area. Additional charges are necessary if there is a mechanical parking lot.

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

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

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

Neither Yokohama City nor Kanagawa Prefecture offers subsidies specifically for large-scale renovation work. The available options can be broadly categorized into four types. The eligibility and application status of these systems may change during the fiscal year, so please confirm with our company or the respective offices before contracting or starting work. (As of October 8, 2026)

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

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

* 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 Should Start Here)

The support system in Yokohama City is mostly based on the “Yokohama City Apartment 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 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, 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, establishing 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 within 30 years and within 7 years”, among others.

*Fees include a system usage fee of 10,000 yen + city application fee of 3,900 yen, etc. It takes 2 to 3 months from application to certification. The validity period of the certification is 5 years.

④ National Energy Conservation Support | Housing Energy Conservation 2026 Campaign

Changes for Fiscal Year 2026The “Child-rearing Green Housing Support Project” for Fiscal Year 2025 has been abolished and reorganized into the successor “Mirai Eco Housing 2026 Project.” Additionally, the “Long-term Excellent Housing Renovation Promotion Project” will end in Fiscal Year 7, and there will be no implementation in Fiscal Year 8. Please be careful not to establish 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 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 Seya Ward, Yokohama City

Seya Ward, Yokohama City, was newly established on October 1, 1969, as a result of the administrative district reorganization separating from Totsuka Ward. According to ward documents, it is located in the westernmost part of Yokohama City, characterized by a long and narrow terrain, and has developed as an agricultural area. Many place names include “yato,” and the Sakai River, Aizawa River, Izumi River, and Akugawa River flow within the ward. The highest point in the ward is Higashinodai (elevation 90.9m). Due to the development centered around lowlands along rivers and valleys, the way buildings deteriorate and the method of scaffolding varies depending on the location.

Source: Yokohama City Seya Ward “Basic Data of Seya Ward” (Population and households are estimated values based on the 2020 national census / Elderly population is from the Basic Resident Register) / Yokohama City “Data on Greenery” (Fiscal Year 2019) / Yokohama City “Building Agreement (Seya Ward)” / Yokohama City Seya Ward “Town Names and Their Origins in Seya Ward”

Buildings in Seya Ward are divided into “four types”

Seya Ward has different historical developments depending on the location, so not only the age of the building but also the location of the building (lowlands along rivers and valleys, urban areas around stations, residential areas with greenery and farmland, and areas around the former Kamiseya Communication Facility) will affect the type of major repairs needed in the next large-scale renovation. Please check which type your building falls under.

Source: Yokohama City Seya Ward “Town Names and Their Origins”／Same “Basic Data of Seya Ward”／Yokohama City “District Planning” List／Yokohama City Seya Ward “Five Merits of Living in Seya ① – Housing Sector -“／Yokohama City “Overview of the Former Kamiseya Communication Facility Area”／Yokohama City Seya Ward “About the Former Kamiseya Communication Facility”

Four Unique Factors in Seya Ward That Damage Buildings

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

Source: Yokohama City Seya Ward “Town Names and Their Origins” / Yokohama City “Flood Hazard Map” / Yokohama City “Landslide Hazard Map” / Yokohama City “Data on Greenery” / Yokohama City “Building Agreements (Seya Ward)”・“District Plans” / Ministry of Land, Infrastructure, Transport and Tourism “2023 Comprehensive Survey on Condominiums” (PDF)

Key Points to Consider When Proceeding with Construction in Seya Ward

*Kakeru Koumuten has five bases in Yokohama City and serves the entire Seya Ward, including Mitsukyo, Aizawa, Akugawa, Kitamachi, Miyazawa, Hongō, and Higashino.

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 determination should be based on the condition of deterioration rather than just the number of years, so if you notice symptoms like those listed below, we recommend an early on-site inspection.

Estimated Repair Cycles by Part (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 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 the Actual Conditions of Large-Scale Repair Work for Condominiums in FY2021”

Examples of Large-Scale Renovation Work

This is a case of exterior renovation work on a mixed-use building handled 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 Survey to Completion of Construction

From the initial inquiry to the 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 will allow 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 rooftop, high places, and leak areas using drones or thermal imaging. For properties in Seya Ward, we will also check the location, whether it is low land or elevated, the height difference of the site, drainage, the condition of trees, access routes, parking, and the distance 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 plans can also be proposed.
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 notifications, visit neighbors to greet them, and set up a bulletin board at the entrance (construction 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 → ironwork & ancillary work in that order. A supervisor will inspect each process and take construction photos.
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 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 provide materials and reports in the following four situations.

* For management associations, it is smooth to decide in advance who will approve additional work (chairperson, repair committee, etc.) 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 avoided by providing prior notice, so Kakeru Koumuten Co., Ltd. thoroughly explains and posts information before construction begins.

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

There are many large-scale repair contractors that cover the Seya 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 their services.

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

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

Check for Warranty and Aftercare Services

When choosing a large-scale repair company, let’s confirm the availability of warranties. If any issues such as leaks occur after the construction, 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 are often confident in their work, making this a key criterion for selecting a contractor.

Warranty periods vary by contractor and the nature of the work, but it is common to see terms ranging from 1 to 10 years. Emergency repairs or partial fixes often do not come with leak warranties. Some contractors also provide 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 support for simple repairs such as partial sealing.

Obtain Estimates from Multiple Contractors (At Least 3 Companies)

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

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

Check This 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 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 having knowledge and experience and managing in-house, responsible construction at a reduced cost becomes possible.

Moreover, contractors that outsource may also be slow to respond 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 how the process proceeds.

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

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

Latest 2026 In the large-scale renovation industry, improper orders linked between design consultants and construction companies have long been a concern. The Ministry of Land, Infrastructure, Transport and Tourism issued alerts 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).

※This content is 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 meeting minutes to ensure transparency
• Confirm the reasons for unusually low design management fees from consultants
• 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 the process will be conducted in accordance with public works methods.

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

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

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

For condominiums, according to the Ministry of Land, Infrastructure, Transport and Tourism’s fiscal year 2021 survey, 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 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, 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 condominiums or mixed-use buildings from 5,000,000 to 15,000,000 yen. Costs may vary depending on the condition of the substrate and whether waterproofing or roofing work is needed, so we provide free on-site estimates.

How often should large-scale repairs be conducted?

Generally, a cycle of 12 to 15 years is recommended, and the actual cycle is most commonly 13 years according to the Ministry of Land, Infrastructure, Transport and Tourism’s survey, with about 70% falling within the 12 to 15-year range. However, the decision should be based on the condition of 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 better 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.

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

For apartments, it typically takes 3 weeks to 2 months, for small-scale 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 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, such as 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 1 to 1.5 years for the establishment of a 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 using subsidies or tax incentives, please also factor in the time for obtaining management plan certification (2 to 3 months from application to certification).

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

Both Yokohama City and Kanagawa Prefecture do not provide 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 barrier-free renovations in common areas (1/3 up to 300,000 yen). If the work includes windows and insulation, it may be eligible for “Advanced Window Renovation 2026” or “Mirai 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 work.

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

It is true if the conditions 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 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 Seya Ward Office within three months of completion. For certified management plan condominiums, there are additional requirements such as raising the repair reserve fund, which takes time to prepare, so it is recommended to start the process more than a year in advance.

Are there any changes to subsidies starting in fiscal year 2026?

Yes. The national “Childcare 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 a 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 the interest rate can be reduced by up to 0.6% per year by obtaining management plan certification and implementing energy-saving and seismic work. Please consult us regarding the decision to postpone waterproofing and tile peeling measures, as this often ends up being more costly in the long run.

Can you handle large-scale repairs for properties with many buildings, like apartment complexes?

You can consult us. Seya Ward was newly established in 1969, separated from Totsuka Ward, and according to ward materials, it has developed as an agricultural area (from the official ward page). For properties with many buildings, it is important to conduct deterioration diagnoses 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 an alternative parking location. 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 Seya Ward, there are three building agreements listed by Yokohama City (updated January 31, 2024), and the district plans include the Seya Station area, Hinatayama area, Seya Akugawa Miyakoshi area, Seya Orohonmachi area, and the former Kamiseya Communication Facility area. The existence and content of agreements regarding appearance and color vary by agreement and plan. You can check what applies to your property through the publicly available information on Yokohama City’s building agreements and district plans, or you can inquire at the Seya Ward Office’s Urban Development Promotion Division (045-367-5631) at the “Community Rule-Making Consultation Corner” for guidance on urban development in the ward. We will also investigate this during our survey. Sharing a color simulation of the completed image can facilitate discussions with neighbors and the local community association.

Are there any differences in construction for buildings located in areas with greenery or farmland, or along low-lying riverbanks?

According to ward materials, Seya Ward is a long, narrow ward located in the westernmost part of Yokohama City, developed mainly along low-lying riverbanks and valleys, with a green coverage rate of 32.9% (6th in the city for the fiscal year 2019). Depending on the location, whether it is low-lying along a river or on a hill, as well as the elevation differences of the site and the condition of the front road, special considerations may be needed for scaffolding installation and material transportation. Kakeru Koumuten Co., Ltd. has its own scaffolding team that will check the site and plan the transportation route and scaffolding layout. Additionally, for buildings near trees, there may be issues with leaves clogging gutters and drains, and moss or algae growing in shaded areas, so we focus on inspecting rooftop drains, drainage areas, wall dirt, and waterproof layer damage. 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, 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 detailed estimates specifying quantities, methods, and materials for each construction 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 methods: ① Pre-determining the contractor and having other companies submit only formal high estimates, known as “dummy estimates,” ② A consultant contracts at an extremely low design supervision fee and receives kickbacks from partner companies, creating collusion, and 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 Construction Bidding Agency Service.”

How many companies should I get estimates from?

最低3社をおすすめします。多すぎると比較しきれず、少なすぎると競争が働きません。大切なのは社数よりも「同じ土俵を作ってから比べること」です。共通の仕様書や数量表を作って同一条件で依頼し、「一式」表記を認めず内訳明細を必須にすると、金額差が範囲の違いなのか単価の違いなのかがはっきりします。

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 2021 survey). By not outsourcing scaffolding work, we can easily control costs in this area, and our in-house scaffolding team can flexibly respond to sudden changes in the schedule or additional work. Kakeru Koumuten Co., Ltd. owns scaffolding materials for about 100 single-family homes and plans scaffolding on-site according to the site conditions.

Can I just have the estimate reviewed while I’m in the middle of getting multiple 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 competitive 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 or drones and propose the minimum necessary repairs.

Can you handle roofing or exterior 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, 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 removal and construction costs as a subsidy, 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 from falling exterior tiles, structural deterioration due to corrosion of rebar, leaks, and a decrease in asset value. Furthermore, for buildings subject to regular reporting under Article 12 of the Building Standards Act, investigations through comprehensive inspections are required under certain conditions, such as when more than 10 years have passed since completion or exterior wall renovations for tiled or mortar-finished walls. In Yokohama City, buildings that are only apartments are not designated as subject to regular 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 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 to 4 million yen, and for three-story steel or RC buildings with 10 to 20 units, it is around 4 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 exterior appearance using color simulations at the same time as repairs to improve occupancy rates.

If you are looking for a large-scale repair contractor in Seya Ward, Yokohama City, contact Kakeru Koumuten Co., Ltd.

Our company is based in Yokohama City and has handled many exterior wall renovations and large-scale repairs for condominiums and apartments in Seya 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 indoors are hot” and other specific requests or future repair plans will be met with optimal solutions.

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

Large-scale Repair Work Service Area

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

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