Hello!
I am Yamanaka from Kakeru Koumuten Co., Ltd., a specialist in roofing, exterior painting, and exterior renovations located in Aoba-ku, Yokohama, Kanagawa Prefecture!
This is a case study of a roof renovation project in Inagi City, Tokyo.
The work involved a roof overlay (cover method) using Eco Granie!
We implemented leak prevention measures through the roof overlay!
Thank you very much for choosing Kakeru Koumuten Co., Ltd. from among many contractors.
目次
Roof Overlay Construction Procedure
1. Existing Ridge and Snow Stops Demolition
We will only dismantle the ridge flashing and snow stops that may obstruct the overlay work.
2. Roofing Installation (Waterproof Sheet)
The roofing material used this time is modified asphalt. It is expected to have double the durability of standard asphalt roofing!

3. Component Processing (Karakusa and Keraba)
We will process and install the keraba and karakusa.
4. Main Body Construction
We will install the main roofing material while securing it with screws on the front side.

5. Sealer and Nailing Board Installation
After finishing the main roofing, we will attach the sealer to the nailing board and then install the nailing board.
This time, we used a cedar nailing board, but there are also nailing boards made of corrosion-resistant resin.

5. Ridge Flashing Processing
We will process and install the ridge cap. We will firmly apply sealing on the inside of the joint.

6. Cleaning
We will remove footprints and debris that have inevitably fallen around the house and in the rain gutters, and do a thorough cleaning.
We strive to leave the area cleaner after the work than it was before!
That concludes the work!
The roofing material used is Eco Grani from Kakeru Koumuten Co., Ltd.
The manufacturer offers a long warranty of 30 years on the base material.
Eco Grani is a lightweight metal roof made of zinc-aluminum steel, which is equivalent to galvalume steel, ensuring high durability.
The surface is coated with natural stone granules, which prevents significant fading and maintains aesthetic appeal over the long term.
Thanks to the stone granules on the surface, it can reduce summer heat and rain noise.
Additionally, it is lightweight, rust-resistant, and excels in durability and seismic resistance.
Eco Grani / Colors
■ Tweed Gray

■ Cafe

■ Onyx

■ Evergreen

This time, we completed the installation beautifully in Evergreen!
The customer was very satisfied!
Thank you very much!
What is the Roof Overlay (Cover Method)?
The roof overlay method involves leaving the current roof almost as it is and placing a new roof on top of it, effectively covering it.
As the name suggests, it is a method of covering a roof with another roof. Therefore, the roof becomes double-layered. This method is also referred to as “overlapping roofing.”
Advantages of the Overlay Method
Since we are placing a “new roof” over the “current roof,” there is almost no need for demolition work, meaning very little waste is generated.
This is the biggest feature and leads to various advantages.
The only part that requires demolition and waste disposal is the ridge cap, so compared to a full roof replacement, the cost is lower.
In 2004, regulations regarding the concentration of asbestos in raw materials were changed (for more details, please visit the Ministry of Health, Labour and Welfare’s website).
Some building materials used in structures constructed before 2004 contain asbestos. Asbestos-containing materials are difficult to demolish due to their high environmental impact, resulting in high costs for both demolition and waste disposal. The roof overlay method, which generates almost no waste, is ideal for such roofs.
Some of you may be wondering, “Is it safe to live in a building that uses asbestos-containing materials?” but rest assured. As long as they are not destroyed or crushed, they will not disperse into the air.
If you are unsure about the type of roof on your home, please feel free to consult with us.
Additionally, we can complete the work in a shorter time frame compared to painting or full roof replacement. A shorter construction period means lower labor costs, which in turn makes the overall cost lower.
This also reduces the psychological anxiety of having to live in an unusual environment.
When scaffolding is set up, you may experience inconveniences such as difficulty entering and exiting or opening windows. Being able to return to your normal life in a short period is a significant advantage.
Our company specializes in roofing work, and the roof overlay method is the most frequently performed service we offer. We are very grateful that we have been continuously engaged in roof overlay projects without interruption.
If you have any concerns regarding your roof, rain gutters, or exterior walls, please consult Kakeru Koumuten Co., Ltd.!
We carry out everything from temporary scaffolding work to roofing and exterior painting entirely in-house. We are confident that our costs, quality, and organization in exterior work are unmatched by other companies!
We welcome competitive estimates with confidence!
We are committed to ensuring that you feel, “I’m glad I chose you!” for every request we receive.
We look forward to your inquiries. Thank you very much.
For helpful information about exterior renovations, click here!
・The Necessity and Timing of Exterior Wall Painting…
・Kanagawa and Tokyo Exclusive | For Those Who Want to Try DIY Exterior Wall Painting! Scaffolding Only! Roof and Wall Painting DIY Plan!
・Introducing Roof Materials That Cannot Be Painted or Recommended!
・What Are the Average Costs of Roof Remodeling? Types of Construction and How to Choose a Contractor
・Introducing Current Roof Materials and Remodeling Methods!
・Roof Renovation | What is Roofing? Introducing the essential building material, roofing sheets!
・What are the market prices for rain gutter repair and cleaning? Tips on timing, fire insurance, and choosing a contractor!
・Renovation store in Yokohama, Kanagawa Prefecture | What is roof overlay (roof cover method)?
We welcome consultations via LINE as well◎
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!


