Isz Co., is one of the biggest Japanese vehicle and diesel engine manufacturing companies


Isz Co., let’s say, is one of the biggest Japanese vehicle and diesel engine manufacturing companies. The company’s concern is to renovate their deteriorated slate roof by not damaging their production line and the existing building infrastructure. 


At first, the company was considering a metal roof cover method for the purpose of waterproofing and reinforcement. However, due to the steel structure of the building plus the air conditioning and equipment that are hung, the company did not want to increase any more weight to the building infrastructure. 

Also, the metal roof cover method is attaching the roofing material to its main building infrastructure with bolts. This is not possible when the production line is still ongoing because the slate powder will fall off during the installation and could cause harm to the machines as well as the workers’ wellbeing.

How SOSEI helps Isz Company:

  • SOSEI method weighs only 2.2 kg to 2.5 kg per square meter while the metal roof cover method weighs 6 kg to 15 kg (depending on the thickness of the steel plate). Even compared, SOSEI is ¼ lighter and superior.
  • Since SOSEI is a spraying method, there is no need to process the existing roof so there is a low risk of objects, slate powder, or asbestos falling during the installation.
  • Apart from the 10-year waterproofing guarantee, SOSEI strengthens the old roofing material and building infrastructure, tested by a punching method. It has been proven that SOSEI is as strong as a metal sheet cover method but provides way less weight to the building infrastructure.

“Toyoko Inc. was born in 1996 in Shizuoka Prefecture, Japan, which has a sea port. Many buildings and houses suffer from erosion due to the salinity of the sea.”

Group 1391
Ken Wanatabe
CEO of Toyokoh