FAQ about discrepancies of insulation materials in parting walls and exterior wall structures not meeting certain qualifications(Other common questions)
FAQ about discrepancies of insulation materials in parting walls and exterior wall structures not meeting certain qualifications(Other common questions)
Please explain the details of the defects related to foamed urethane.
Regarding parting walls, although it is written in construction certification documents that glass wool (fiberglass) is to be used as insulation material in parting walls, we confirmed that foamed urethane was used in certain buildings. There is a possibility that these buildings do not meet the sound insulation standards of apartments required by the Building Standard Law.
Regarding exterior walls, since foamed urethane was used to bind sidings and gypsum boards in certain buildings, the binding method and necessary length between wall backings did not meet qualifications certified by the Minister of Land, Infrastructure and Transport. There is a possibility that these buildings do not meet standards defined in laws and regulations.
How were the properties subject to defects related to foamed urethane identified? Is there a possibility that other properties will have similar defects?
A list prepared at the time when panels with foamed urethane were manufactured contains apartments which the subject panels were delivered. By checking this list against the list of apartments we have constructed, we confirmed the apartments with foamed urethane in parting and/or exterior walls.
How were the defects related to foamed urethane discovered?
During the course of investigations where we measured the thickness of parting walls, we discovered that certain buildings used foamed urethane as an insulation material.
Why was foamed urethane used instead of glass wool (fiberglass)?
At that time, we were examing measures to increase productivity by manufacturing certain materials at factories. To simplify the binding method of materials for parting walls (gypsum boards), a method using foamed urethane as an adhesive was adopted.
Are there any issues regarding the safety of apartments using foamed urethane?
Regarding parting walls, fire resistance is ensured by double-layered gypsum boards. Regarding exterior walls, one-hour fire resistance performance tests were conducted at the time, and no issues regarding safety have been confirmed. However, since the specifications do not meet law regulations, repairs are necessary.
Regarding exterior walls, since foamed urethane was used to bind sidings and gypsum boards in certain buildings, the binding method and necessary length between wall backings did not meet qualifications certified by the Minister of Land, Infrastructure, Transport and Tourism. There is a possibility that these buildings do not meet standards defined in laws and regulations.
Regarding parting walls, there is a possibility that sound insulation levels do not meet standards required by the Building Standard Law.
We are currently consulting with designated administrative agencies regarding repair methods. Repairs will be conducted after repair methods are decided.
