【Naka-ku, Yokohama】｜【Roof Repair】｜We performed roof overlay work on the slate to Alma!

BEFORE

AFTER

Hello!
We are 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 an exterior renovation project in Naka-ku, Yokohama.
The work involved a roof overlay (cover method) by Alma and the construction of a storage shed door!

The existing roofing material was slate containing asbestos, and we received an inquiry stating, “The roofing material is falling off, so please take a look.”
The roofing material was falling off from various places, and there was a risk of leaks, so we proposed a roof overlay after checking the condition of the underlying structure.

The customer requested, “Please suggest roofing materials that will last for 20 years,” so we proposed Nichiha/Alma.

Thank you very much for choosing Kakeru Koumuten Co., Ltd. from among many contractors.

Roof Overlay Construction Procedure in Naka-ku, Yokohama

1. Demolition of Existing Ridge and Snow Stops

We will dismantle unnecessary parts (ridge cap) for the roof overlay (cover method)! The existing wooden purlins were significantly deteriorated and had become rotten.

The lifespan of wooden purlins is approximately 10 to 15 years. Exceeding the lifespan can lead to corrosion and discoloration, resulting in the ridge cap coming loose or being blown away.

2. Roofing Installation (Waterproof Sheet)

The roofing used is Jouyu Pulp Industry/Sunlight G!
It is made of modified asphalt roofing, which is said to have double the lifespan of regular asphalt roofing.
With its role as the primary waterproofing layer, if the roofing is properly installed, there will be no leaks! We will secure it firmly to prevent it from blowing away.
The roofing material used this time, Alma, has a lifespan of approximately 20 to 25 years, so we used a roofing sheet with a matching lifespan!

4. Accessory Processing (Karakusa & Keraba)

Before the main roofing work, we will process and install accessories such as keraba and karakusa!
The materials used for the accessories are galvalume steel sheets.

4. Main Construction (Nichiha/Alma)

After processing the components, we will install the Alma main body up to the ridge! We will also securely apply single cement during the construction.
Once we have installed up to the ridge, we will set up the necessary materials to fix the ridge board, known as the kanban. There are types of kanban made from cedar and resin, and this time we used resin!
The resin type is expected to have twice the durability compared to the cedar type! This material is also aligned with the durability of the roofing material itself!

5. Processing of Ridge Metal and Sealing at Various Locations

Next, we will process and install the ridge metal. We will securely apply sealing on the inside of the joints. For the wall edge, we will process and install a component called a rain stop metal.
The screws used for fixing are made of stainless steel, which is resistant to rust!

6. Cleaning

We will clean up the debris that has fallen onto the balcony and rain gutters. We will thoroughly remove items like nails and metal scraps that could lead to injuries.

Storage Door Sealing Work

1. Dismantling Existing Storage Door

We will remove the storage door!

2. Plywood Installation

We will be installing new plywood! We used decorative veneer!

3. Completion

This concludes the construction! We also received a request from the customer for a storage door project, which we completed together!

About the Roofing Material

The roofing material used is Nichiha’s Aruma.
Aruma comes with a 10-year manufacturer warranty.
Since it uses natural stone that is baked onto 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.

It excels in finish, durability, sound insulation, and wind resistance, and is lightweight compared to other roofing materials, which reduces the sway during earthquakes, making it effective for earthquake resistance.
In the overlay (cover) work we performed this time, the roof becomes double-layered, which increases the weight, but Aruma is a lightweight roofing material, making it suitable for overlay (cover) work.

Colors

■ Black AR

■ Gray AR

■ Green AR

■ Brown AR

■ Camel AR

This time, we completed the roof work with Brown AR very well!
The customer was very satisfied, and I was also very happy!
Thank you very much!

Please check out other roofing work achievements here!

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.
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).
Some building materials used in constructions completed before 2004 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, “Is it safe to live in a building that uses 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, it can be completed in a shorter period than painting or complete roof replacement. A shorter construction period means lower labor costs, which in turn makes the cost lower.
The psychological anxiety of having to live in an unusual environment is also reduced.
When scaffolding is set up, there may be inconveniences such as difficulty in entering and exiting or opening windows. Being able to return to normal life in a short period is a significant advantage.

Our company specializes in roofing work, but the roof overlay method is the most frequently performed work we do. We are very grateful that we are continuously able to carry out roof overlay method projects without interruption.

Roof Material	Nichiha/Alma
Manufacturer Warranty	10 years
Expected Durability	About 20 years
Color Used This Time	Brown AR

Leave Your Roof Repairs in Naka-ku, Yokohama to Kakeru Koumuten!

Our company has extensive experience in roof renovations in Naka-ku, Yokohama.
We are happy to assist with partial roof repairs, including roof overlay work, roof replacement, and leak repairs.
If you have any questions or concerns, such as “I just want to know the estimate for a roof renovation” or “I want to know about roofing materials,” please feel free to contact us!

We have handled many roof renovations in Naka-ku, Yokohama, and have a deep understanding of the needs of our local customers.

“I want it to last long with just one renovation.”

“I want to keep costs down with minimal emergency repairs.”

“I want to improve insulation because it’s hot indoors.”

We will provide optimal solutions for your specific requests.

Summary

This time, we showcased our roof overlay work and storage door construction in Naka-ku, Yokohama!
If you have a slate roof containing asbestos, replacing it will incur high disposal costs for the waste materials.
If you are considering roof repairs, we recommend roof overlay work before the underlying structure deteriorates.

Estimates and inspections are, of course, free! If you have any issues with roofs, rain gutters, exterior walls, or exteriors, please consult Kakeru Koumuten Co., Ltd. in Aoba-ku, Yokohama!

Kakeru Koumuten Co., Ltd. is a remodeling company strong in exterior renovations, and we carry out everything from temporary scaffolding work to roof work and exterior painting completely in-house.
When it comes to exterior renovation work, we are confident that we will not be outdone by other companies in terms of “cost, quality, and efficiency”!

We are confident in our exterior renovations, so we welcome competitive estimates!
We also offer comprehensive construction guarantees and aftercare maintenance, and we have received positive feedback for our cost performance and appropriate proposals that align with our customers’ future life plans!

We want you to think, “I’m glad I asked!” Therefore, we take every request we receive seriously.

We also have information on roof construction costs and pricing plans for the roof overlay (cover method), so please feel free to take a look!

We look forward to your inquiries. Thank you very much.

Helpful information about exterior renovations can be found here!

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