Basic Policy for Product Safety and Quality Control in the Housing Business

Sumitomo Forestry believes that popularizing durable, high-quality houses as social assets plays an important role in creating a prosperous society. Based on this belief, and taking the opportunity of the enforcement of the Excellent Long-Term Housing Promotion Act in Japan in June 2009, the Company formulated a basic policy for product safety and quality control in its housing business in fiscal 2009.

 

Basic Policy for Product Safety and Quality Control in the Housing Business

  • Make houses more reliable by improving their basic functions
  • Increase future options for layout to accommodate changes in lifestyles
  • Enhance maintenance programs to support long-term upkeep
  • Monitor information on any production faults, and share information on handling faults promptly

Sumitomo Forestry offers homes that integrate seismic resistance, durability, better insulation efficiency, Net Zero Energy Houses (ZEHs), the promotion of universal design, and easy upkeep to improve all aspects of home performance so as to offer customers homes where they can live in peace of mind and comfort for many years to come.

Design performance evaluation

The Company is actively promoting the use of the Japanese Housing Performance Indication System*1 for customer peace of mind and safety as well as enhancing the value of property. In fiscal 2017, under the Japanese Housing Performance Indication System*2, Implementation of Design Performance Evaluation reached 98.9%, Implementation of Construction Performance Evaluation reached 97.9%, and the acquisition of Excellent Long-Term Housing certification reached 93.3%.

*1 The Japanese Housing Performance Indication System: Third-party evaluation of design performance at the time of design and of construction performance upon completion so that customers can objectively assess the quality and performance of a house. The system comprises 10 evaluation items, including structural stability, fire safety, alleviation of deterioration, and thermal environment.

*2 The ratio of the number of applications against the total number of detached houses constructed, including extensions and/or alterations (applications for design and construction performance evaluation, April 1, 2017 – March 31, 2018) in the Housing and Construction Division.

Japanese Housing Performance Indication System Implementation Rate

FY 2013 FY 2014 FY 2015 FY 2016 FY 2017
Design performance evaluation* 100.6% 97.7% 98.6% 98.8% 98.9%
Construction performance evaluation 95.4% 94.9% 97.3% 97.8% 97.9%

* The implementation of design performance evaluation has been the percentage in the number of acquisitions for the design performance evaluation during the term for detached houses built (including buildings that have not yet started construction in that term) up until fiscal 2014. However, it was changed to the percentage in the number of acquisitions for the design performance evaluation for buildings that have started construction in that term as of fiscal 2015.

Page Top

Excellent Long-Term Housing Certification

Sumitomo Forestry sets the standard specifications for its Sumitomo Forestry Home houses to exceed the highest level of Excellent Long-Term Housing*1 certification conditions*2 (applying the evaluation under the Japanese Housing Performance Indication System). From product development through to construction and after-service, the Company has established its framework for product safety and quality control in order to deliver high quality homes with superior overall balance.

*1 Excellent Long-Term Housing: A life-long housing certification system of Ministry of Land, Infrastructure, Transport and Tourism which aims to popularize housing that will help realize a society that values its housing stock.

*2 Detached housing is evaluated for durability, seismic resistance, ease of maintenance and energy efficiency in accordance with the Japanese Housing Performance Indication System.

Ratio of houses certified as Excellent Long-term Housing for new custom-built housing

FY 2013 FY 2014 FY 2015 FY 2016 FY 2017
Ratio of houses certified as Excellent Long-term Housing for new custom-built housing 90.7% 91.2% 92.7% 93.3% 93.3%

Excellent Long-Term Housing Standards and Standard Performance of Sumitomo Forestry Home Houses

Certification Type Certification Criterion Standard Performance of Sumitomo Forestry Home Houses
Durability Long lasting Rating measures for deterioration class 3
Measures to allow regular inspection
Equivalent to highest level 3
Seismic Resistance Strong to earthquakes Rating of earthquake resistance 2 or higher Equivalent to highest level 3
Maintenance Requirement Easy maintenance home Rating measures for maintenance level 3 Equivalent to highest level 3
Energy-saving performance Energy-saving house House Rating measures for energy conservation level 4 Equivalent to highest level 4

* The higher the rated level, the better evaluated.

Framework for Product Safety and Quality Control

  • Undertaking development such as new technology, materials, housing products and lifestyle proposals based on consumer needs and owner surveys.
  • The Housing and Construction Division and Tsukuba Research Institute are collaborating in experiments at validation facilities and testing of prototypes, promoting the creation of products that incorporate customer feedback, including even in the details of guarantees.

Product Development

A dedicated designer responsible for the work

A dedicated designer responsible for the work

  • Sumitomo Forestry uses a unique system to check design and structure at the time of contracting and through the final design stage.

Design

  • The Materials Selection Subcommittee, which meets once every month to decide upon all materials, conducts design reviews. All materials are checked to ensure that they meet the acceptance and quality standards set by the Tsukuba Research Institute and the Materials Selection Subcommittee.
  • The Quality Improvement Committee, which meets once every two months, shares information on materials that have been newly accepted, and discusses improvements to materials that have already been accepted. During fiscal 2017, they reported and discussed progress relating to three themes.

Materials Procurement

Construction Management

Construction Management

  • Sumitomo Forestry centrally manages and shares up-to-date information on the construction, process management, quality control and safety management of each building through its own site management system.
  • Each on-site operator, contractor manager and construction manager during such stages as foundation, construction and completion, conducts inspections which are managed using a construction management record. Additionally, the Head Office inspection division checks the status of the inspection and management.

Construction

Regular inspection

Regular inspection

  • Sumitomo Forestry includes 25 years of regular inspections with its homes. This provides support over the long term to ensure a long life in these important living spaces through commercial inspections every ten years for 30 years.
  • Sumitomo Forestry has developed a 60-year Regular Inspection System that offers renovation and maintenance proposals and manages maintenance records in order to support its customers.

After-Sales Support


Renovation

  • The performance and reliability of Sumitomo Forestry’s proprietary materials used in anti-seismic reinforcement and so on are verified at the Tsukuba Research Institute. In addition, we are advocating seismic retrofitting by undergoing a technological evaluation of the Japan Building Disaster Prevention Association.
  • Sumitomo Forestry Home Tech Co., Ltd. joined the All Japan Ryokan Association* in fiscal 2017 and focuses on renovations of hotels and Japanese Inns.

* All Japan Ryokan Hotel Association: The Association promotes Japanese Inns and Hotels throughout Japan to be more sanitary facilities, conduct better maintenance and stable management among other aspects of accommodation businesses.

Before Renovation of Japanese Inn

Before Renovation of Japanese Inn

After Renovation

After Renovation

Renovation (Purchase for Resale)

  • In order to make a diagnosis of the seismic resistance and deterioration conditions of a condominium, the original construction drawings and specifications are checked, and construction reviews, reinforcement checks, concrete strength measurements and other inspections are conducted in collaboration with third-party surveyors. Conducting major renovation work properly based on the results of these inspections increases the life-span of the building. In addition, all of the inspection results and descriptions of the renovation work are disclosed at the time of sale.
  • Sumitomo Forestry has a number of support programs in place, including issuing its own warranty, providing existing housing home buyer’s defect warranty and latent defect insurance, and offering regular after-sales maintenance checks during the first year.
Under Renovation

Under Renovation

After Renovation

After Renovation

  • Sumitomo Forestry and Kumagai Gumi Co., Ltd. have entered into a capital partnership to further collaboration between Sumitomo Forestry Home Tech Co., Ltd. and K&E K.K., which are Group companies of the respective companies. Sumitomo Forestry Home Tech is in charge of interior renovations that utilize wood while K&E is in charge of building renovations such as the exterior that fully leverages the abilities of a general contractor. Our ability to renovate the entire building heightens the buildings value as an asset.

Page Top

Seismic Resistant Housing: Development of K-type Corner Braces and RGS Panels

K-shaped corner brace bearing walls use 24 mm thick structural plywood that is in order to store 75 mm thick glass-wool insulation inside. This method has great workability because the materials are light, and it underwent a technological evaluation by the Japan Building Disaster Prevention Association (6.0KN/m² standard bearing wall).

GS panels for renovation (RGS panels) are used as a seismic resistance method to limit deformation by installing these right and left panels (structural plywood with a 24 mm thickness) made of special metals sandwiching highly rigid and highly damping rubber in vertical members. Even greater workability is provided by dividing these panels into top and bottom pieces as well. The method underwent a technological evaluation by the Japan Building Disaster Prevention Association (6.1KN/m² bearing wall).

RGS Panel

RGS Panel

Page Top

BF Method

Sumitomo Forestry started selling the Big-Frame Construction Method (BF Method) as a product for three-story building products in February 2005 and expanded this method to two-story products in October 2009 as well as to products with fire-resistant specifications in four-story buildings in April 2015. Thereafter, as awareness of customers grew about risks such as disasters, the BF Method that had further evolved to provide greater strength in high seismic resistance matched customer needs and is now one of the company's main products.

The proprietary BF Method from Sumitomo Forestry is the first in Japan to realize the wooden beam Rahmen structure, which is used in high-rise buildings, in wooden houses.

The Rahmen structure is designed to stand up to horizontal forces such as earthquakes and wind through rigid-joints that unify the columns and beams with the fixings. The BF Method uses big columns with a large cross-section of 560 mm which is equivalent to roughly five standard 105 mm columns as well as incorporates structural materials in addition to a combination of metal-to-metal joints to achieve a robust Rahmen structure.

The beams and bases of the big columns join strongly thanks to the metal-to-metal joints. This brings about horizontal vibration resistance equal to a 22.4 (times/meter) shear resistance of walls. We ensure seismic resistance while being able to provide both large spaces and wide openings.

In addition, expanding and introducing a variety of original technology can support an even wider range of design requirements. Twin-bolt columns (shear resistance of walls equivalent to 33.6 times/meter) that doubles metal joints as well as double-large columns that layer two large columns (shear resistance of walls equivalent to 44.8 times/meter) provide freedom in floor plans and more spaciousness even on land with many restrictions. The pre-straight timber beams are large span beams increasing the freedom of design for built-in garages used for multiple vehicles, large open living rooms, multi-dwelling homes in addition to a wide range of other purposes.

Sumitomo Forestry conducts vibration tests on testing model of structural framework made using the BF Method as well as full scale structures to examine seismic resistance in anticipation of a large-scale earthquake.

The full-size testing model for a three-story building constructed with the BF method cleared testing easily for vibrations of a maximum acceleration of 2,699 gal, which is equivalent to the Great East Japan Earthquake, and is 3.3 times the Great Hanshin-Awaji Earthquake (maximum acceleration of 818 gal). Our technology has been proven tough through a total of 22 harsh vibration tests; two of which were conducted at a magnitude of 7 equal to the Great East Japan Earthquake and 20 of which at a magnitude of 7 equal to the Great Hanshin-Awaji Earthquake. We also estimate strong aftershocks after a massive earthquake by implementing a repetition of a total of 246 vibration tests. We have repeatedly conducted testing with strong vibrations from a magnitude of 4 to a weak 6 and beyond to 7 to ensure continued seismic resistance of the structural framework.

In this way, the BF method responds to the needs of customers with powerful structures to bring security as well as flexible designs able to provide comfortably spacious spaces.

 Strong Big Column with a Width More Than Five Times a Standard Pillar

Strong Big Column with a Width More Than Five Times a Standard Pillar

Realizing a Robust Rahmen Structure via Metal-to-Metal Joints

Realizing a Robust Rahmen Structure via Metal-to-Metal Joints

Page Top

Promotion of Universal Design

Sumitomo Forestry is a pioneer in establishing soft closers for all indoor furnishings such as sliding doors and hinged doors as an initiative to increase the safety of residents. In addition, an all flat design that does not create any level differences in flooring is now a standard specification while convex corners for inner walls and wall-mounted convex sections have an R-shape specification around living spaces and halls. We have set the standard specifications for the width of hallways to 780 mm to allow the use of wheelchairs with the assumption that wheelchairs and care will be necessary in the future. We also flexibly respond to customer requirements through a freedom in design that includes slopes to entrances and the installation of home elevators.

In addition, Sumitomo Forestry is placing its strength in the design of living spaces to satisfy the needs of customers such as roof balconies without level differences from the interior, heat shocks, and the Air-Dream Hybrid total air conditioning system that reduces house dust and realizes a comfortable space without any temperature fluctuations. Sumitomo Forestry also provides comfortable bedroom environments with original wooden interiors that have indirect lighting to offer better sleep quality and reduce fatigue in indoor environments perfect for sleeping.

Page Top

CSR