If you are looking for a waterproofing contractor in Aoba-ku, Yokohama
please contact Kakeru Koumuten
Kakeru Koumuten is a company specializing in exterior renovations based in Yokohama.
We receive many requests for waterproofing work in Aoba-ku, Yokohama, ranging from single-family homes to apartment buildings.
“Reasons why Kakeru Koumuten is chosen in Aoba-ku”
“About the costs of waterproofing work”
“How to choose a waterproofing contractor”
“About grants and subsidies applicable to waterproofing work in Aoba-ku”
We will explain the above four points!
This will definitely be helpful for customers considering waterproofing work in Aoba-ku, Yokohama, so
please take a look!
Reasons why Kakeru Koumuten is chosen for waterproofing work in Aoba-ku, Yokohama
One reason our company is entrusted with waterproofing work by customers in Aoba-ku, Yokohama is that
we have a base in Yokohama,
and we have unique strengths in waterproofing work that cannot be imitated by other companies, which has received high praise from many customers.
we are absolutely confident in “cost,” “quality,” and “plans”, so
we would appreciate it if you could compare our estimates with those of other companies.
Because we are confident, we welcome competitive estimates!
1.Facilities Specialized in Exterior Renovation
Kakeru Koumuten Co., Ltd. has organized the following warehouses and material storage areas to provide more affordable and faster waterproofing and other exterior renovation services.
We have established five bases centered around Aoba-ku, Yokohama for material storage and showrooms.
In-House Scaffolding Materials


We own the scaffolding materials necessary for temporary scaffolding required for waterproofing work, allowing us to assemble temporary scaffolding in-house.
By conducting scaffolding work with our own scaffolding team instead of outsourcing, we can also reduce scaffolding construction costs.
Since everything is handled in-house, we can significantly reduce costs by shortening the construction period!
We have enough scaffolding materials for approximately 50 single-family homes!
Storage of materials in our large in-house warehouse

We store roofing materials and waterproofing components.
By ordering a large quantity of materials at once, we can purchase materials at a lower cost!
Additionally, we always have waterproofing materials in stock, allowing us to respond quickly to emergency waterproofing work!
In-house sorting of waste materials
In waterproofing work, various waste materials are generated.
Most contractors dispose of them all together, but by sorting and recycling waste materials, significant cost reductions in waste disposal fees can be achieved.
Exterior Renovation Dedicated Showroom


In our showroom, not only can you have meetings, but you can also
directly check the actual structure and colors.
2.Complete In-House Construction
One of Kakeru Koumuten’s major strengths is complete in-house construction.
From inquiry to project completion, everything is handled by Kakeru Koumuten Co., Ltd. This allows us to keep costs down while providing high-quality waterproofing work.
Additionally, one representative will assist you from the estimate to the completion of the work.
Since the person in charge does not change, whether it’s the sales representative or the construction management representative, smooth communication is possible.
We are confident in our construction plans and costs, so we welcome competitive estimates!
3. Various Permits and Skilled Workers

We have obtained construction industry permits and permits for industrial waste collection and transportation!
We also have qualified personnel on staff, and we are confident in our construction techniques.
We are capable of handling large-scale waterproofing projects, such as those for factories!
4. Warranty and Aftercare
Waterproofing work comes with a guarantee!
Depending on the type of waterproofing work, we provide a 5 to 10-year leak guarantee.
If you have any questions about the guarantee, please click on the image above!
In the unlikely event that leaks are not resolved after the waterproofing work, we will take responsibility and respond accordingly!
Additionally, aftercare maintenance is available every year, and we will send you a DM reminder for aftercare maintenance once a year.
During aftercare maintenance, we will check the entire waterproofing and assess the condition of any deterioration.
5. Flexible and Prompt Response
Our company is equipped to handle various troubles and situations.
If we cannot access the rooftop for waterproofing checks, we will utilize drones to assess the condition.
We can also conduct investigations using thermal imaging cameras during leak investigations.
We will respond according to your wishes.
We also accept emergency measures for sudden leaks!
Since our sales and construction management are not separated, one dedicated representative will handle everything from the estimate to the completion of the work!
Changing representatives frequently can lead to miscommunication regarding the details and precautions of the work, which could cause problems, so we maintain a system where the representative remains the same.
6. Human Resource Development
We are creating various building models to improve our skills and conducting practical training.
To ensure that each staff member can handle various buildings, we regularly provide technical training.
Possible subsidies and grants for waterproofing work in Aoba-ku, Yokohama補助金、助成金
If damage from natural disasters is recognized, it may be covered by fire insurance.
For waterproofing, potential damage from natural disasters could include “holes in waterproof sheets caused by flying objects or falling debris due to wind disasters.”
If you are unsure whether it is covered by fire insurance, please feel free to contact us!
Property tax reduction system for condominiums that have undergone large-scale repairs (Condominium Longevity Promotion Tax System)
To promote the longevity of condominiums, for those that meet certain requirements, large-scale repairs that contribute to longevity must be completed between April 1, 2023, and March 31, 2027, and necessary documents must be submitted to the Tax Division of the Ward Office within three months of the completion of the work. There is a system that reduces the property tax amount for the following fiscal year by half for the relevant condominium.
Condominium Longevity Promotion Tax System
Yokohama City Official Website
About the cost of waterproofing work
Examples of Waterproofing Work
| Construction Details |
| Urethane Waterproofing Ventilation Buffer Method / High-Strength Urethane Type Existing Waterproofing: PVC Sheet Waterproofing |
| Materials Used |
| Waterproofing: AGC Polymer Building Materials / Saracene A (High-Strength Urethane) Ventilation Sheet: QV Sheet Decompression Tube: Stainless Steel Replaced with Renovation Drain |
| Price Range |
| 700,000 to 800,000 yen |
| Construction Period |
| Approximately 2 weeks |
| Completion Month |
| May 2024 |
| Inquiry Details |
| We have received the following inquiries from our customer. ・There are wrinkles and bulges in the waterproof sheet on the rooftop, so we are worried about leaks. ・We would like an estimate for a complete waterproof renovation, not just partial repairs or a top coat. ・We learned that urethane waterproofing has high waterproofing properties, so we would like an estimate for urethane waterproofing. ・Since this is our first waterproofing project, we would like to compare estimates. |
Our Proposal
Since you expressed a desire to renovate using a long-lasting method rather than protective agents like top coats, we proposed a complete “urethane waterproofing project” for the rooftop.
If urethane waterproofing is applied using the adhesion method, air rising from the building can cause bulges in the waterproof layer, so we proposed the “urethane waterproofing ventilation buffer method.”
The ventilation buffer method involves applying a ventilation buffer sheet over the entire area before installing the urethane waterproofing.
By applying the ventilation buffer sheet first, the air rising from the building is suppressed by the ventilation sheet and expelled through the “ventilation tube.”
This can prevent the most common issue in waterproofing, which is bulging of the waterproof layer!
After explaining the materials and methods, you entrusted the project to us among the four estimates you received!
Timing for Waterproofing Work
Leaks Have Already Occurred
If leaks have already occurred, it is necessary to address the issue promptly before the damage spreads.
If left unattended, it can negatively affect the interior and underlying structures, so it is essential to stop the leaks quickly.
Bulging or Cracking of the Waterproof Layer
If the waterproof section is cracked, it can lead to rainwater intrusion.
If the waterproof layer is bulging, it indicates that moisture is accumulating within the layer.
Bulging can lead to cracks, which can result in leaks, so early detection and action are necessary.
Moss or Mold Growth
Moss or mold can develop due to the accumulation of moisture or rainwater.
This can be caused by poor drainage or sinking of the waterproof layer due to aging.
Exceeding the Durability Period
Generally, the durability period for waterproofing work is 10 to 20 years.
Of course, the durability can vary depending on the method and materials used, but for some types of waterproofing, it is recommended to apply only the surface protective agent (top coat) approximately every 8 years (such as urethane waterproofing or FRP waterproofing).
We recommend regular inspections starting from 5 years after construction.
Understanding the types of waterproofing and performing appropriate maintenance is essential.
If you are unsure about the type of waterproofing, please send us a photo via email or LINE, and we will help you determine it!
Types of Waterproofing Work
1. Urethane Waterproofing
Urethane waterproofing is a method where liquid polyurethane resin is applied in layers to the waterproofing surface.
Since it is liquid before curing, it can be applied to complex shapes, and unlike sheet waterproofing, it can be installed without seams, which is a significant advantage.
It can be widely applied to balconies, rooftops, and more.
For more details on the advantages, disadvantages, and maintenance methods of urethane waterproofing, please refer to the article below.
For more on waterproofing work | Urethane Waterproofing, click here!
2. Rubber Sheet Waterproofing
Rubber sheet waterproofing involves adhering synthetic rubber sheets to the surface to prevent water intrusion.
This type of waterproofing is commonly used on large areas such as rooftops.
Compared to urethane waterproofing, it has the advantage of faster installation since there is no waiting for drying, but it is not suitable for complex surfaces.
For more details on the advantages, disadvantages, and maintenance methods of rubber sheet waterproofing, please refer to the article below.
For more on waterproofing work | Rubber Sheet Waterproofing, click here!
3. PVC Sheet Waterproofing
PVC sheet waterproofing is a waterproof sheet made of polyvinyl chloride, and like rubber sheet waterproofing, it adheres the sheet to the surface to prevent water intrusion.
Like rubber sheets, it is not suitable for complex shapes. Although the cost is higher than rubber sheets and urethane waterproofing, its long durability is an advantage.
We provide detailed explanations about the advantages and disadvantages of PVC sheet waterproofing, as well as maintenance methods, in the article below.
For waterproofing work | Click here for information on PVC sheet waterproofing!
4. Long Sheet Waterproofing
Long sheet waterproofing, officially known as “anti-slip vinyl flooring sheet,” is commonly applied in shared areas of apartments and on stairs where people walk.
As the name suggests, it is slip-resistant and has high durability and abrasion resistance, making it suitable for walking areas.
Additionally, it comes in various designs, excelling in aesthetic appeal.
However, it tends to be more expensive, and since it does not overlap seams like rubber sheets or PVC sheets, it may give a slightly lower impression of waterproofing capability.
It is rarely used in areas such as rooftops of apartments where people do not frequently enter.
We provide detailed explanations about the advantages and disadvantages of long sheet waterproofing, as well as maintenance methods, in the article below.
For waterproofing work | Click here for information on long sheet waterproofing!
5. FRP Waterproofing
FRP waterproofing involves creating a waterproof layer by solidifying glass mat with epoxy resin to prevent rainwater intrusion.
It is commonly applied on single-family home balconies, with an overwhelmingly short construction period, often completed in as little as one day.
Due to its lightweight and low cost, it seems that about 80% of single-family home balconies use FRP waterproofing.
However, it is not suitable for installation on large areas, making it less appropriate for rooftop applications.
We provide detailed explanations about the advantages and disadvantages of FRP waterproofing, as well as maintenance methods, in the article below.
Waterproofing Work | Click here for FRP Waterproofing!
6. Asphalt Waterproofing
Asphalt waterproofing is a waterproof sheet made by impregnating synthetic fiber non-woven fabric with asphalt.
The waterproofing shown in the photo is a method where asphalt waterproofing is pressed down with cinder concrete.
This type of waterproofing is used in buildings with large areas such as rooftops of schools and commercial facilities.
There are various methods of asphalt waterproofing, each with its own advantages and disadvantages, but a significant advantage is its high durability.
For more details on the advantages, disadvantages, and maintenance methods of asphalt waterproofing, please refer to the article below.
Waterproofing Work | Click here for Asphalt Waterproofing!
How to Choose a Waterproofing Contractor
There are many waterproofing contractors available in Hodogaya-ku, Yokohama.
Among the numerous contractors, many people may feel “I don’t know who to ask..”.
Choosing the right contractor can be challenging at first, so here are 5 points to keep in mind when requesting waterproofing work.
● Have extensive experience in waterproofing work
● Check for aftercare and warranty availability
● Obtain estimates from multiple contractors (at least 3 companies)
● Confirm whether the contractor performs waterproofing work in-house
● Carefully review the details, processes, and materials used in the waterproofing estimate
By confirming the above 5 points, you will be able to choose a reliable contractor.
Confirm whether they have extensive experience in waterproofing work
About 10-20% of waterproofing work troubles are caused by construction defects during the installation.
It is important to hire an experienced and trustworthy contractor to prevent troubles!
You need to refer to the contractor’s website for their track record and reviews to make a judgment.
Some contractors showcase their achievements on social media platforms like Instagram, so checking those can also be effective!
It is also effective to look at waterproofing companies using review sites for reference!
A particularly recommended review site is “Google”.
Since contractors cannot delete low ratings on their own, it is a reliable source of reviews.
If there are many negative reviews or no reviews at all, it may be wise to refrain from requesting their services.
Check if there is aftercare maintenance and construction warranty
In case any construction defects or issues arise after the work is done, let’s confirm if they provide a “construction warranty“!
Contractors who offer warranties tend to be more confident in their work, making them more trustworthy companies!
If waterproofing work is done, make sure to take photos of hidden areas during the process for confirmation!
Check for leaks during rainy weather after the waterproofing work, and if there are any issues, contact the contractor immediately, as it will facilitate smooth communication shortly after the work is completed!
Additionally, to detect any issues early, confirm whether they provide thorough aftercare maintenance!
Since non-specialized contractors may not notice signs of problems or troubles, having specialized contractors perform regular aftercare maintenance can help prevent issues before they arise!
Our company sends out aftercare maintenance DM every year, so if desired, annual aftercare maintenance is possible!
Obtain estimates from multiple contractors (at least three)
When requesting waterproofing work, be sure to obtain estimates from multiple contractors.
We recommend obtaining estimates from at least three companies.
Even for the same waterproofing work, costs may vary between contractors, and warranties and after-services may differ as well.
Moreover, obtaining multiple estimates makes it easier to negotiate prices. To request at the lowest possible cost, it is essential to get estimates from several contractors.
When comparing estimates, check not only the costs but also the “types of materials used” and “construction methods,” and compare the details!
Confirm if they perform waterproofing work in-house
Check if they perform waterproofing work in-house!
If a sales company investigates and then requests subcontractors, it will take more time and cost.
Additionally, there may be cases where your requests are not fully communicated to the subcontractors, leading to troubles.
By having one company handle everything from sales to construction, responsible waterproofing work can be done quickly and cost-effectively. Kakeru Koumuten handles everything from on-site surveys to actual construction in-house!
In the unlikely event that a leak or trouble occurs, having a company with its own craftsmen allows for quick response and resolution to any issues!
Carefully check the details, process, and materials used in the waterproofing estimate
Even with the same waterproofing work, there are various types such as “method,” “materials,” and “process,” and it is necessary to carry out the work with the most suitable method and materials depending on the construction location and existing substrate.
For example, even with the same urethane waterproofing, there are different types of processes such as “adhesion method” and “ventilated buffer method,” and there are various types of urethane waterproofing materials, including “high-strength specifications,” “heat-insulating specifications,” and “anti-slip specifications.” Therefore, it is essential to confirm whether the proposed construction details are appropriate for the location!
It is important not to judge solely based on cost, but to carefully check whether “the method is appropriate for the substrate?” and “are the materials suitable?”
Thus, if the materials used are only “urethane waterproofing materials,” make sure to check the product name and confirm what kind of materials they are!
If you are looking for a waterproofing contractor in Aoba-ku, Yokohama, please contact Kakeru Koumuten Co., Ltd.
Our company handles many waterproofing projects in Aoba-ku, Yokohama.
Our greatest strength is that we can carry out everything from proposals to temporary scaffolding installation and waterproofing work in-house!
Kakeru Koumuten Co., Ltd. promises “high-quality waterproofing work at low cost”, and we have received high praise from many customers.
We continue to update our construction performance records every year, and we will strive to improve quality to satisfy even more customers in the future.
We are also happy to handle small partial works!
In addition to waterproofing work, we can carry out roofing work, exterior wall painting, and exterior wall overlay methods all in-house.
We are confident that we will not be outdone by other companies in terms of cost, quality, and organization for exterior work!
We welcome competitive estimates with confidence!
Estimates are completely free, and if our company is found to be inferior to others, please feel free to decline!
Aoba-ku, YokohamaFor exterior renovations in Aoba-ku, Yokohama, click here!
For exterior wall painting in Aoba-ku, Yokohama, click here!
For roof renovations in Aoba-ku, Yokohama, click here!
For exterior wall overlay work in Aoba-ku, Yokohama, click here!
For leak repairs in Aoba-ku, Yokohama, click here!
Features of Aoba-ku, Yokohama
Aoba-ku, Yokohama is located in the western part of the city, with a population of about 200,000. Geographically, it is a flat area with many residential neighborhoods and commercial facilities. The rivers and small paths flowing through the area create a harmonious environment between nature and the cityscape. Access is very convenient, with the JR Yokosuka Line and the Shonan-Shinjuku Line running through, making it easy to travel within the city and to Tokyo from Hodogaya Station. Additionally, major roads run through the area, making it excellent for travel by car. Furthermore, it is also close to Yokohama Station, making access by car or train simple!
One of the attractions of Aoba-ku is its natural environment. The area boasts large parks and green spaces, perfect for strolling and outdoor activities. There are also historical streets and buildings, providing many spots to experience the region’s history and culture. As a residential area, it features both single-family homes and condominiums, making it a popular choice.
If you live in Aoba-ku and have any concerns regarding waterproofing work or issues related to your home, please feel free to contact us!
Waterproofing Service Areas
Kakeru Koumuten Co., Ltd. accepts requests throughout Kanagawa Prefecture and Tokyo.
List of Areas in Aoba-ku, Yokohama
Arai-cho, Hodogaya-ku, Yokohama / Imai-cho, Hodogaya-ku, Yokohama / Iwai-cho, Hodogaya-ku, Yokohama / Iwasaki-cho, Hodogaya-ku, Yokohama / Iwama-cho, Hodogaya-ku, Yokohama / Okazawa-cho, Hodogaya-ku, Yokohama / Kasumidai, Hodogaya-ku, Yokohama / Kaito-cho, Hodogaya-ku, Yokohama / Kamadai-cho, Hodogaya-ku, Yokohama / Kamaya-cho, Hodogaya-ku, Yokohama / Kamisugita-cho, Hodogaya-ku, Yokohama / Kamihoshikawa, Hodogaya-ku, Yokohama / Kariba-cho, Hodogaya-ku, Yokohama / Kawashima-cho, Hodogaya-ku, Yokohama / Kawabe-cho, Hodogaya-ku, Yokohama / Kobe-cho, Hodogaya-ku, Yokohama / Gontazaka, Hodogaya-ku, Yokohama / Sakaigaki-cho, Hodogaya-ku, Yokohama / Sakaigaki-honcho, Hodogaya-ku, Yokohama / Sakamoto-cho, Hodogaya-ku, Yokohama / Sakuragaoka, Hodogaya-ku, Yokohama / Shinsakuragaoka, Hodogaya-ku, Yokohama / Setogaya-cho, Hodogaya-ku, Yokohama / Tsukimidai, Hodogaya-ku, Yokohama / Tenno-cho, Hodogaya-ku, Yokohama / Tokiwadai, Hodogaya-ku, Yokohama / Nishikubo-cho, Hodogaya-ku, Yokohama / Nishitani-cho, Hodogaya-ku, Yokohama / Hatsuneoka, Hodogaya-ku, Yokohama / Hanamidai, Hodogaya-ku, Yokohama / Higashikawashima-cho, Hodogaya-ku, Yokohama / Fujizuka-cho, Hodogaya-ku, Yokohama / Butsukou-cho, Hodogaya-ku, Yokohama / Butsukou-nishi, Hodogaya-ku, Yokohama / Hozen, Hodogaya-ku, Yokohama / Hoshikawa, Hodogaya-ku, Yokohama / Hodogaya-cho, Hodogaya-ku, Yokohama / Mineoka-cho, Hodogaya-ku, Yokohama / Minezawa-cho, Hodogaya-ku, Yokohama / Miyata-cho, Hodogaya-ku, Yokohama / Myojindai, Hodogaya-ku, Yokohama / Wada, Hodogaya-ku, Yokohama
Consultations via LINE are also very welcome◎
AAA is a young company with an average age in the early 20s, but our technology is second to none.
One of our greatest strengths is that we can do all of our own scaffolding, roofing, and painting work. In this industry, where work is generally divided, we are able to provide a complete set of services, which saves time and effort in management and reduces costs. Above all, if there is any trouble, we will come to you right away!
We can confidently declare this. We are the youngest and most friendly renovator in Kanagawa!





