Nakano-ku, Tokyo | We have completed roof replacement work using Hiranbi 220!

BEFORE

AFTER

Hello!
We are 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 exterior renovations in Nakano-ku, Tokyo.
The work this time involves a roof overlay (cover method) project using Hiranbi 220!
The existing roof is made of corrugated metal roofing material.

This time, the roof overlay project is being carried out as a measure against leaks.

On this page, we 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.

Roof Overlay Project Construction Photos

1. Existing Roofing Material Demolition

We will dismantle and remove the existing roofing material!

2. New Sheathing Installation

After dismantling the existing roofing material, we will process and install new sheathing (structural plywood) to fit the dimensions!

3. Roofing Installation (Waterproof Sheet)

We will lay down the roofing sheet (waterproof sheet) on the base! The roofing used is Jouyu Pulp Industry/Sunlight G!
This material is modified asphalt roofing, which is said to have double the durability of regular asphalt roofing.
As a primary waterproofing measure, if the roofing is properly installed, there will be no leaks!
We will ensure it is firmly attached so it doesn’t blow away!

4.Accessory Processing (Karakusa & Keraba)

Before the main roof construction, we will process and install accessories such as keraba and karakusa sheet metal!
The materials used for the accessories will be galvalume steel.

5.Main Construction (Inagaki Shouji/Hiranbee)

After processing the accessories, we will install the Hiranbee main roofing up to the ridge!
Once the roofing is completed up to the ridge, we will install necessary materials called “kanban” to secure the ridge cap. There are two types of kanban: cedar and resin, and this time we used the resin type!
The resin type is expected to have twice the durability of the cedar type!

6.Ridge Cap Processing & Sealing at Various Locations

Next, we will process and install the ridge cap. We will firmly apply sealing on the inside of the joints. At the wall edge, we will process and install a component called rain stop sheet metal.
The nails and screws used for fixing will be made of rust-resistant stainless steel!

7.Cleaning

We will clean up the debris that has fallen on the balcony and rain gutters. We will thoroughly remove items like nails and metal scraps that could cause injuries. We will also wipe away any footprints left on the roof to keep it clean!

About Roofing Materials

The roofing material used is Hiranbi 220 from Inagaki Shouji.
Hiranbi 220 comes with a manufacturer warranty of 15 years for the coating and 25 years for perforation.
For re-roofing and roof overlay, we also provide a 10-year construction warranty!
If there are any leaks within 10 years, we will make repairs free of charge.
Made of Galvalume steel, it is resistant to rust.
The formed panels feature Ayame folding and rippled processing to prevent distortion and enhance strength, as well as improve rain drainage and aesthetic effects.

Additionally, 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 a good earthquake countermeasure.
In the overlay (cover) work we performed this time, the roof becomes double-layered, which increases the weight, but Hiranbi is a lightweight roofing material, making it suitable for overlay (cover) work.

Color

Extreme – MAX Type
■ Gray Silver

■ Silver Black

■ Sepia

■ Moss Green

■ Bamboo Green

■ Midnight Blue

■ Jet Black

■ Dark Brown

■ Bright Red

Standard Type
■ Steel Black

■Marron Brown

■J Silver

You can choose from these options!

This time, the roof overlay work was finished very well in Bright Red!
Thank you for your request!!

Please check out other roofing work examples from here!

What is the Roof Overlay Method?

The roof overlay method involves leaving the current roof almost as it is and placing a new roof on top of 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 before 2004 contain asbestos. Asbestos-containing materials are difficult to dismantle 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 consult us.

Additionally, the construction can be completed in a shorter period than painting or complete replacement. A shorter construction period means lower labor costs, which in turn makes the costs 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 entering and exiting or not being able to open 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.

Leave Your Roof Renovation in Tokyo to Kakeru Koumuten!

Our company is based in Aoba-ku, Yokohama, but we also have extensive experience in roof renovations in Tokyo.
We are happy to assist with roof overlay work, roof replacement, and even partial roof repairs such as leak fixes.
If you have any questions or concerns like “I just want to know the estimate for roof renovation” or “I want to know about roofing materials,” please feel free to contact us!

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 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 won’t 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 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 seriously and work diligently on it.

We also have information on roofing 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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