Roof Overlay (Cover Method) | Ota-ku | We Performed Roof Overlay by Ridgeway!

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 Ota-ku, Tokyo.

This construction project involves the roof overlay (cover method) using Ridgeway!

The existing roofing material is a horizontally laid metal roof, but there were leaks occurring.
Several companies attempted to repair the leaks before us, but the leaks persisted, leading to our consultation!
The underlying structure was weakened in some areas, so we installed new sheathing throughout.
Due to the complex shape of the roof, we proposed the roof overlay (cover method) using flexible shingle material (Ridgeway)!

On this page, we will explain the actual results of the work performed by Kakeru Koumuten!

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

Roof Overlay (Cover Method) Construction Steps

1. Dismantling Existing Ridge Cap

We will dismantle the unnecessary existing ridge cap for the overlay method!

2. Installing New Sheathing

This time, we will be performing a cover work after adding new plywood. We will process and install the new plywood according to the dimensions!

3. Installing Roofing (Waterproof Sheet)

Next, we will install the roofing sheet (waterproof sheet)!

The roofing used is Tajima Roofing/Tadis Self!
It is a delayed adhesive modified asphalt roofing material, 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 regular roofing.
As a primary waterproofing measure, if the roofing is solid, there will be no leaks!
We will ensure it is firmly attached to prevent it from blowing away.

4. Fabrication of Accessories (Kera and Karakusa)

Before the main roof construction, we will fabricate and install accessories such as kera and karakusa sheet metal!
The materials used for the accessories are galvalume steel sheets.

5. Main Construction (Asahi Fiberglass/Ridgeway)

After processing the ridgeway components, we will install the main body of the ridgeway up to the wall! We will apply single cement at the overlapping areas during the installation.
The cause of this leak was the skylight. It seems that the existing skylight did not have a discard board metal sheet installed to prevent leaks, which likely led to the issue.
For the new installation, we have properly installed a discard board metal sheet to enhance waterproofing.
Once the roofing is completed, we will install the necessary materials to secure the ridge cap, known as the “kanban.” There are types of kanban made from cedar and resin, and this time we used the resin type!
The resin type is expected to have three times the durability compared to the cedar type!

6. Ridge Cap and Sealing at Various Locations

We will process and install the ridge cap. We will thoroughly apply sealing on the inside of the joints.
The nails and screws used for securing are made of stainless steel, which is resistant to rust!

7. Cleaning

We will clean up any debris that has fallen onto the balcony and rain gutters. We will thoroughly remove items like nails and metal fragments that could cause injuries. We will also wipe away any footprints left on the ridge cap to ensure everything is clean!

About the Roofing Material (Ridgeway)

The roofing material used is Ridgeway from Asahi Fiberglass.
Ridgeway 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, which helps reduce maintenance costs!
The use of fine natural stones on the surface means you won’t be troubled by rain noise.
Additionally, being a lightweight roofing material, it is strong against earthquakes and has good seismic resistance.

*After installation, small pieces of the surface decorative stone may fall off for about a week, but this does not indicate a quality issue.

Color

■Dual Black

■Harvard Slate

■Vintage Green

■Dual Brown

■Earthtone Cedar

This time, the roof work with Earthtone Cedar turned out exceptionally well!
The customer was very satisfied, and I was also very happy!
Thank you very much!

Please check out other roofing project achievements from 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 the existing one, 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 material is produced.
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 website).
Some building materials used in structures constructed before 2004 contain asbestos. Because materials containing asbestos have a high environmental impact, their demolition is also difficult, leading to high costs for both demolition and waste disposal. The roof overlay method, which produces almost no waste, is ideal for such roofs.

Some may wonder, “Is it safe to live in a building that uses materials containing asbestos?” 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 with us.

Additionally, the construction can be completed in a shorter timeframe compared to painting or a full 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 unusual environment 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 the roof overlay method is the most frequently performed type of work we undertake. We are very grateful that we have been continuously engaged in roof overlay projects without interruption.

Roof Material	Asahi Fiber Glass/Ridgeway
Manufacturer Warranty	10 years
Expected Durability	25 to 30 years
Color Used This Time	Earthtone Cedar

Leave Your Roof Renovation in Ota-ku, Tokyo to Kakeru Koumuten!

Our company is based in Aoba-ku, Yokohama, but we also have extensive experience in roof renovations in Ota-ku, Tokyo.
We are happy to assist with roof overlay work, roof replacement, and partial roof repairs such as leak fixes.
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!

Long-Term Reliability

All the roofing materials we use come from reliable products that offer long-term warranties. For example, the Ridgeway from Asahi Fiberglass 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 concerns regarding roofs, rain gutters, exterior walls, or exteriors, please consult Kakeru Koumuten Co., Ltd. in Aoba-ku, Yokohama!

Kakeru Koumuten is a remodeling company strong in exterior renovations, and we perform complete in-house construction from temporary scaffolding to roofing and exterior painting.
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 also provide comprehensive construction guarantees and aftercare maintenance, receiving high praise for our appropriate proposals that match cost performance and 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 roofing costs and pricing plans for roof overlay (cover 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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