[Kanazawa-ku, Yokohama] | We performed roof repair using the roof overlay (cover method)!

BEFORE

AFTER

Hello!
This is Kakeru Koumuten Co., Ltd., a specialist in roofing, exterior painting, and exterior renovations located in Yokohama, Kanagawa Prefecture!

This is a case study of an exterior renovation in Kanazawa-ku, Yokohama.
The roof repair this time involves a roof overlay (cover method) from Colonial to Super Galtect!

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

Construction Data for Kanazawa-ku, Yokohama

Roof Overlay Construction Procedure

1. Demolition of Existing Ridge and Snow Stops

We will dismantle unnecessary parts (ridge cap) for the overlay method! This time, we also removed the water heater! 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. Installing Roofing (Waterproof Sheet)

Next, we will install the roofing sheet (waterproof sheet)! The roofing used is Tajima Roofing/Tadis Self!
This material is a delayed adhesive modified asphalt roofing, which is said to have double the durability of regular asphalt roofing.
Due to its adhesive properties, it sticks to the substrate, providing higher waterproofing compared to standard roofing.
With the role of primary waterproofing, if the roofing is solid, there will be no leaks!
We will ensure it is firmly attached so it doesn’t blow away. There are various features and durability ratings for roofing sheets, so let’s choose a roofing sheet considering new roofing materials and the environment!

3.Accessory Processing (Karakusa & Keraba)

Before the main roof construction, we will process and install accessories such as keraba and karakusa!
The accessories used are the genuine accessories from Galtect, made of SGL copper plate!

4. Main Construction (Aiji Industry/Super Galtect)

After processing the accessories, we will install the Galtect main body up to the ridge! At the same time, we will also install the genuine Galtect snow guards!
For securing the roofing materials, we use Aiji Industry’s renovation screws.
These renovation screws are made of stainless steel and are treated with disco processing.
They are resistant to rust and significantly improve wind resistance!

Once we have installed up to the ridge, we will set up the necessary materials for fixing the ridge board, known as the kanban. We offer three types of kanban: cedar, resin, and galvalume steel, and this time we used the resin type!
The resin type is expected to have2times the durability! If you use cedar kanban, which has a lower durability than the roofing material, it will need to be replaced in about 10 years. It is recommended to match the durability of the roofing material and the kanban!

5. Ridge Metal Processing & Sealing at Various Locations

Next, we will process and install the ridge cap. We will thoroughly apply sealing on the inside of the joints. For the wall edges, we will process and install a component called a rain gutter board.
The packing screws used for fixing are made of stainless steel, which is resistant to rust!
By using screws instead of nails for fixing, we enhance wind resistance as they do not pull out like nails!

6. Cleaning

We will clean up any debris that has fallen onto balconies and other areas. We will thoroughly remove items like nails and metal scraps that could cause injuries. Additionally, we will wipe off any footprints left on the roof to keep it clean.

This completes the roof overlay (cover method)!

About the Roofing Material

The roofing material used is the Super Galtect from Aijii Industry.
The Super Galtect comes with a manufacturer warranty of 15 years for the coating and 25 years for perforation.
We also provide a 10-year construction warranty!
Made of SGL steel plate, it is resistant to rust.
Insulation material is tightly adhered from edge to edge of the roofing material, creating a metal plate that integrates steel and insulation.
When installed, insulation is applied even to the parts where the roofing materials overlap, and the surface is coated with a high heat-reflective paint, allowing for a cool summer and a warm winter.
Additionally, it has soundproofing properties, which reduce the sound of rain.
Moreover, it is lightweight compared to other roofing materials, which reduces the sway during earthquakes, providing earthquake resistance.
It excels in finish, durability, insulation, soundproofing, and wind resistance, and the Super Galtect from Aijii Industry is the most frequently used in our construction achievements, making it highly regarded!

Color

■Shade Black

■Shade Brown

■Shade Blue

■Shade Moss Green

■Shade Charcoal

■Shade Wine Red

You can choose from these 6 colors!

This time, the cover work was done in Shade Charcoal, and it 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 examples from here!

Roof Material	Aiji Giken/Super Galtect
Manufacturer Warranty	Coating 15 years, Red rust 20 years, Puncture 25 years
Expected Durability	About 40 years
Color Used This Time	Shade Charcoal

What is the Roof Overlay (Cover Method)?

The roof overlay method involves leaving the existing 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 layered, it is also referred to as “layered roofing.”

Disadvantages of the Overlay Method

While the roof overlay method has many advantages, there are, of course, some disadvantages as well.
First and foremost, this method assumes that the existing roof maintains a certain level of durability. If the existing roof is significantly deteriorated or corroded, the overlay method cannot be applied, and it may be necessary to remove it and proceed with a complete roof replacement.
Additionally, since a new roofing material is layered on top of the existing roof, the overall weight of the roof structure increases. This increase in weight may impact seismic resistance. Special care should be taken in areas where seismic resistance is crucial or in older buildings, as it may affect durability.

Moreover, the roof overlay method is not applicable to all roofing materials. In particular, with tile roofs, the overlay method can be challenging. Depending on the combination of existing and new roofing materials, there may be compatibility issues that make installation unsuitable.

Advantages of the Overlay Method

The overlay method involves placing a “new roof” over the “existing roof,” which means that demolition work is almost unnecessary, resulting in minimal waste.
This is its most significant feature, leading to various advantages.

The only part that requires demolition and waste disposal is the ridge cap, so compared to roof replacement, the cost is lower.
In 2004, regulations regarding the concentration of asbestos in raw materials were changed (for details, please visit the Ministry of Health, Labour and Welfare website).
Some building materials used in structures built before 2004 contain asbestos. Asbestos-containing materials are difficult to dismantle 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.

You may be wondering, “Is it safe to live in a building that uses asbestos-containing materials?” 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, the construction can be completed in a shorter time than painting or roof replacement. A shorter construction period means lower labor costs, which in turn makes the overall cost lower.
The psychological anxiety of having to live in an environment that is different from usual is also reduced.
When scaffolding is set up, you may experience inconveniences such as difficulty entering and exiting or being unable to open windows. Being able to return to your normal life in a short period is a significant advantage.

Our company specializes in roofing work, but currently, the demand for roof overlay methods is increasing, so let’s carefully consider whether this method is suitable for your home’s roof and what type of work is appropriate for your current roof.

Moreover, the roof overlay method is the most frequently performed work by our company.
We are very grateful that we are continuously able to carry out roof overlay work, so if you have any concerns or questions regarding the roof overlay method, please do not hesitate to contact us!

Leave your roof repairs in Kanazawa-ku, Yokohama to Kakeru Koumuten!

Community-focused service

As an exterior renovation company based in Aoba-ku, Yokohama, we handle many roof repairs and renovation projects in Kanazawa-ku, which is also within Yokohama City, so we deeply understand the needs and concerns of residents in Kanazawa-ku.

Kanazawa-ku is characterized by its rich natural environment, surrounded by the sea and mountains.
However, since the coastal areas often experience strong winds, it is important to choose roofing materials that emphasize “wind resistance.”
If you are close to the sea, the manufacturer’s warranty for roofing materials may change due to the effects of saltwater.

It is necessary to select roofing materials that consider the building’s location and environment, and to thoroughly check “Are there any changes to the warranty?” “Are the roofing materials suitable for the environment?” before choosing materials.

Whether you want to “make it last long with one renovation,” “keep costs as low as possible,” “increase insulation performance because the indoors are hot,” or “just do a temporary fix for the roof,” we will propose the optimal plan tailored to your specific requests and environment!

Summary

This is the record of roof repair work in Kanazawa-ku, Yokohama!
This time, we installed stage scaffolding and carried out the roof overlay work entirely in-house!

Super Galtect is lightweight and has a high durability lifespan, making it a suitable roofing material for the overlay method!
When considering the overlay method, it is important to check not only the roofing materials and estimate costs but also the finer details such as “roofing sheets,” “nail boards,” and “fasteners” to avoid future troubles!

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

We are happy to assist with everything from roof overlay work and roof replacement to partial roof repairs!

Kakeru Koumuten is a remodeling company strong in exterior renovations, and we carry out everything from temporary scaffolding work to roofing and exterior painting entirely in-house.
Regarding exterior renovation work, we are confident that we do not fall short compared to other companies in terms of “cost, quality, and efficiency.”

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 cost performance and appropriate proposals tailored to our customers’ future life plans!

“I’m glad I asked them!” We take every request seriously to ensure you feel this way.

We also have information on roof construction 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!

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