Ideas for bright future are what MUGEN dedicate itself to construction business in the world

We are a Japanese enterprise named “MUGEN”, meaning infinity in Japanese.


Roofs of the building will change in future!!
The new roofing system is coming up!!

Ideas for bright future are what MUGEN dedicate itself to constructionbusiness in the world

In October 2021, we successfully completed development and merchandising of a new roofing system being made of precast concrete under unprecedent concept of the roofing. This product is designed to use as roofs fitting for concrete and concrete based structure, and also presumably for ALC and steel structures.

Since this roof product is made in one-piece molding with various new technologies in quite a few angles, we decided to apply a patent on same. In addition, we are to apply some patents on the wall structure which support the said roof. We believe that we will probably be able to acquire patents on these ideas of ours, after our close checking of existence of any resemble produce through international patent data and internet information.


Photo of precast concrete roof proto type installation:
Two-stories reinforced concrete construction; installing one-piece molding roof; checking fitting condition of inserts under the roof and connecting brackets on the wall


The figure on the above is the overall view of this patent application. Details of the precast concrete roof can be found in the P.C.T. International Patent Application Documents. The figure below shows a one-story building for which this patent application was applied. The foundation will be concrete and the walls will be precast

There are 154 countries who join in the international patent organization. It is best to apply for a patent in all these countries, but considering cost-effectiveness, etc., we decided to apply for same in 10 advanced patent countries or more and unable to do so in more than 140 countries unfortunately.

However, there are opinions from various parties that there might be many companies that are interested in this patent pending in countries other than those where the patent was applied, and therefore want to obtain a patent in their own country or intend to use it as a new roofing product in future. Hence, we would like to ask companies in all countries for their cooperation in the questionnaire regarding patents described at the end of this site.


Building construction methods that can use precast concrete roof:
(1) Precast concrete construction method
(2) Concrete method
(3) ALC construction method
(4) Prefabricated building construction method
(5) Steel building construction method
(6) Block building construction method
Usage of precast concrete roof
(1) Apartment house
(2) Small and medium-sized buildings

The validity period of the acquired patent is set to 20 years from the filing date of the patent application, which is common to all countries. In addition, we will pay the registration office expenses for 20 years (a small amount considering the acquired rights), so-called operating expenses for each year, to the authorities, although there are some differences depending on the country.

When applying for a patent in advanced patent countries, we will ask a professional patent attorney’s office, but if not, we will ask a lawyer’s office or law firm to receive the patent application. We recommend you to ask an office with a reliable and competent representative to ensure that the procedure proceeds quickly. The application fee varies depending on the country, but in the case of Japan, it is expected to be about US $ 6,000 at the time of filing and US $ 2,000 at the time of requesting examination, for a total of about US $ 8,000.

International application notification form (copy)


One-story building experimental photo


Place the R-curve precast concrete wall on a flat concrete foundation and install the rising part of the building. In the subject P.C.T. international patent pending a different technology is used from the viewpoint of waterproofing.


Lifting work of precast concrete roof: Rectangle with width 2.4m x length 5.2m; weight about 2.5t, Screw-shaped insert that connects to the wall is embedded to the bottom of the precast concrete roof.


Precast concrete one-story building before exterior designing: Usually, most of them have a square shape, but this building has curved shape corners which give this building a soft image

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Precast concrete one-story building after exterior designing: Main uses to be houses for elderly people living alone; small offices; toilets; etc..
Size: 4m wide X 8m long, 32㎡

Steel structure precast concrete structure


​1. Front photo [Assembly]

Independent foundation. Frontage 6m.

Pillar: Square steel pipe 150mm x 150mm.

Precast concrete

600mmX250mm, L = 6m.


2. Side photo [wall setting]

Precast concrete 2.6m wide X 6m long

Intermediate beam: Precast concrete 300mmX200m

Floor: Precast concrete 2.4m X 6m, Area 14.4㎡

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3. Front / side [roof setting]

Roof: Precast concrete

Area 2.4m X 7.5m = 18㎡.

Weight 6.5t


4. Front/Side [Completed photo]

Prototype experiments went as planned and as our basic design.

Building area 6mX12m = 72m2 2 stories;

the inserts at the bottom of the roof also fitted in the metal fittings on the wall.

Steel roof panel


The photo shows a steel roof panel that was previously patented. In its production, however, it was difficult to produce properly, though structural design of the roof is theoretically rational.

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Welding of steel frames is not a problem, but welding of the side iron plate and galvanized iron plate which is made of a thin material is a big problem, because the welded part will melt. We also tried fillers such as caulking, but we couldn’t finally make the roof into a product. Since the steel roof panel turned to be unsuccessful, the issue of what to do with the roof panel remained.

The precast concrete roof of this P.C.T. international patent pending has solved this problem. Roof panels made by cutting, assembling, and welding over a dozen steel frame materials require a great deal of labor and cost. Above all, the steel roof panel had a crucial defect of leakage, which were least expected to a roof.

The integrally molded precast concrete roof is produced simply by pouring concrete into the formwork and can be mass-produced. Although the product itself has a disadvantage of being heavy, there is no need to worry about water leakage because it is integrally molded. In addition, water leakage in the connection of P.C. concrete panels has been completely prevented with our epoch-making ideas and technical capabilities.