

Hello!
This is Yamanaka from Kakeru Koumuten Co., Ltd., a specialist in roofing, exterior wall painting, and exterior renovations located in Aoba-ku, Yokohama, Kanagawa Prefecture!
This is a case study of an exterior renovation project we undertook in Hachioji City, Tokyo, commissioned by Company K.
There are several types of exterior renovations, and the work we performed this time was a roof overlay (cover method) project (Ridgeway)! We worked on both the main roof and the lower roof of this residence!
We performed a cover method project from asbestos-containing colonial roofing to Ridgeway!
This page will explain the actual results of the work done by Kakeru Koumuten!
Thank you very much for choosing Kakeru Koumuten Co., Ltd. from among many contractors.
目次
- 1 Roof Overlay (Cover Method) Construction Steps
- 1.1 1. Dismantling of Existing Roof Ridge Flashing
- 1.2 2. Installing Roofing (Waterproof Sheet)
- 1.3 3. Fabrication of Components (Curved, Eaves, Valley)
- 1.4 4. Main Body Construction (Asahi Fiberglass/Ridgeway)
- 1.5 5. Ridge Metal, Rain Guard Metal Processing, and Sealing at Various Locations
- 1.6 6. Cleaning
- 1.7 Colors
- 2 What is the Roof Overlay (Cover Method)?
- 3 For roof renovations in Tokyo, trust Kakeru Koumuten Co., Ltd.!
Roof Overlay (Cover Method) Construction Steps
1. Dismantling of Existing Roof Ridge Flashing


We will dismantle the existing roofing materials (ridge cap, snow guards) that are unnecessary for the
2. Installing Roofing (Waterproof Sheet)

It is a delayed adhesive modified asphalt roofing material, which is said to have twice the lifespan of regular asphalt roofing. Due to its adhesive properties, it has a high degree of adhesion to the roofing materials, providing excellent waterproofing! As a primary waterproofing measure, if the roofing is properly installed, there will be no leaks!
We will ensure it is securely adhered to prevent it from blowing away.
3. Fabrication of Components (Curved, Eaves, Valley)


The materials used for the characters are SGL steel plates.
4. Main Body Construction (Asahi Fiberglass/Ridgeway)


Once we have installed up to the ridge, we will place a necessary material called a “kanban” to secure the ridge metal. The kanban can be made of cedar or resin, and this time we used a resin type!
The resin type is expected to have three times the durability compared to the cedar type!
5. Ridge Metal, Rain Guard Metal Processing, and Sealing at Various Locations


We will process and install a component called rain gutter flashing at the wall edge.
We use stainless steel nails and screws that are resistant to rust!
6. Cleaning

The roofing material used is the Ridgeway from Asahi Fiberglass.
Ridgeway comes with a 10-year manufacturer warranty.
Since it uses natural stone that is baked on the surface, it is a roofing material that does not require painting, thus reducing maintenance costs!
Because it uses fine natural stones on the surface, you won’t be troubled by the sound of rain.
Additionally, it is a lightweight roofing material, making it strong against earthquakes and providing seismic resistance.
Colors
■ Dual Black

■ Harvard Slate

■Vintage Green

■Dual Brown

■Earthtone Cedar
This time, the roof work using Harvard Slate turned out exceptionally well!
The customer was very satisfied, and I was also very happy!
Thank you very much!
Please check out other roofing work achievements from here!
What is the Roof Overlay (Cover Method)?
The roof overlay method involves leaving the current roof almost intact and placing a new roof on top of it, effectively covering it.
Literally, it is a method of covering a roof with another roof. Therefore, the roof becomes double-layered. Since the roof is laid over, it is also referred to as “overlapping roofing.”
Advantages of the Overlay Method
Since a “new roof” is placed over the “current roof,” demolition work is almost unnecessary, meaning that very little waste is generated.
This is the biggest feature and leads to various advantages.
The only parts that require demolition and waste disposal are the ridge caps, so compared to complete roof replacement, the cost is lower.
In 2004, regulations regarding the concentration of asbestos in raw materials were changed (for details, please refer to the Ministry of Health, Labour and Welfare website).
Building materials used in constructions completed before 2004 may contain asbestos. Asbestos-containing materials are difficult to demolish due to their high environmental impact, and the costs for demolition and waste disposal are also high. The overlay method, which generates almost no waste, is ideal for such roofs.
Some may wonder if it is safe to live in buildings that use asbestos-containing materials, but rest assured. As long as there is no destruction or crushing, it will not disperse into the air.
If you are unsure about the type of roof on your home, please feel free to consult us.
Additionally, we can complete the work in a shorter time frame compared to painting or re-roofing. A shorter construction period means lower labor costs, which in turn makes the expenses more affordable.
This also reduces the psychological anxiety of having to live in an environment that is different from usual.
If scaffolding is set up, there may be inconveniences such as difficulty entering and exiting or being unable to open windows. Being able to return to normal life in a short period is certainly a significant advantage.
Our company specializes in roofing work, but roof overlay (cover method) construction is the most frequently performed service we offer. We are very grateful that we have been continuously engaged in roof overlay (cover method) construction without interruption.
| Roof Material |
|
|---|---|
| Manufacturer Warranty | 10 years |
| Expected Durability | 25 to 30 years |
| Color Used This Time |
Harvard Slate
|
For roof renovations in Tokyo, trust Kakeru Koumuten Co., Ltd.!
Our company is based in Aoba-ku, Yokohama, but we also have extensive experience in roof renovations in Hachioji, Tokyo.
We are happy to assist with everything from roof overlay projects, roof replacements, to partial roof repairs such as leak fixes.
“I just want to know the estimate for the roof renovation” or “I want to know about roofing materials”—if you have any questions or concerns, please feel free to contact us!
Long-term Reliability
All roofing materials we use come from highly reliable products that offer long-term warranties. For example, the Ridgeway from Asahi Fiberglass that we used this time comes with a 10-year manufacturer warranty, allowing you to use it with peace of mind for a long time after just one renovation.
Ridgeway is a lightweight roofing material that excels in durability and cost performance, but we also offer roofing materials with even higher durability and better insulation properties.
Summary
Estimates and inspections are, of course, free! If you have any issues with your roof, rain gutters, exterior walls, or exterior structures, please consult Kakeru Koumuten Co., Ltd. in Aoba-ku, Yokohama!
Kakeru Koumuten is a remodeling company strong in exterior renovations, and we carry out everything from temporary scaffolding work to roofing and exterior painting completely in-house.
We are confident that in terms of “cost, quality, and organization”, we do not fall behind compared to other companies!
We are confident in our exterior renovations, so we welcome competitive estimates!
We offer comprehensive construction guarantees and aftercare maintenance, and we have received positive feedback for our appropriate proposals that match our customers’ future life plans and cost performance!
“I’m glad I asked them!”—we take every request seriously to ensure you feel this way.
We also have information on roofing costs and pricing plans for the roof overlay method, so please take a look if you’re interested!
We look forward to your inquiries. Thank you very much.
Helpful information about exterior renovations can be found here!
・Hachioji, Tokyo | We performed renovations including exterior wall painting using premium silicone, rain gutter replacement, and face work!
・Setagaya-ku, Tokyo | Exterior wall painting | We performed exterior wall painting using water-based ceramic silicone!
・Setagaya-ku, Tokyo | We performed renovations including full exterior wall painting and partial joint replacement!
・Popular colors for exterior wall painting! We introduce recommended color combinations!
・Waterproof construction menu | Information about waterproof construction costs!
・Latest! Subsidies in Kanagawa Prefecture! We will introduce information about grants and reduction systems!
・What is waterproof construction? We will introduce the merits and construction methods of waterproof construction!
・What is asphalt waterproofing? We will introduce the merits and demerits!
・What is Urethane Waterproofing? What are the cost averages? We will also introduce the benefits and drawbacks!
・What is FRP Waterproofing? What are the cost averages? We will introduce the benefits and drawbacks!
・What is Sheet Waterproofing? What places are recommended? We will introduce recommended sheets!
・How much does exterior wall painting cost? Are there any tips to reduce costs?
・About Joint and Sealing Work | We will introduce the cost averages and construction methods!
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!



