Specialist trader of nonferrous metals and producer of metal roofing materials.

About us

Q.What type of company is Yamauchi Metal?

A.We mostly wholesale non-ferrous metal materials and also handle work on the metals. We also produce and sale a variety of original metal roofing products.

Q.What goods do you handle?

A.We handle a range of shapes of non-ferrous metals including copper, aluminum and stainless steel. We also handle metal roofing products and products related to metal roofing assembly for foundations.

Q.What kind of work can you do on the metal?

A.For non-ferrous metals (copper, brass, aluminum and stainless steel) we can perform a variety of mechanical procedures and surface work including cutting, bending, contracting and drilling on a variety of shapes (sheets, strips, pipes, poles, angles and flat bars).


Q.What kinds of stainless steel do you have? (Varieties, surfaces)

A.Materials: We handle the widely used SUS304 as well as SUS430 and SUS316. Work: the most general 2B finish with some brilliance, #400, a ground version of 2B, and HL (hairline), which is a long, continuous finish.
LinkIconClick here for Stainless steels

Q.Does stainless steel rust?

A.Yes. It does rust although not much. Passive layers of rust appear if iron adheres to the surface. However, by choosing a variety appropriate for the environment and positioning and by performing appropriate cleaning and maintenance the beauty of stainless steel is semi-permanent.

Q.How do I maintain the stainless steel?

A.A simple water-cleaning process can avoid most rust after using a neutral cleaner at least once a year, depending on the amount of sediment on the surface.

Q.Do you have your own original stainless steel colors?

A.We have metallic black, copper brown and camel brown. Please check our color catalogue.
LinkIconClick here for the NAS-coat


Q.What kinds of aluminum do you have? (Varieties surfaces)

A.They are broadly categorized into pure aluminum and aluminum alloys. Pure aluminum is metal with over 99% aluminum, aluminum alloys are mainly aluminum with small quantities of magnesium, manganese, silicon, copper, and zinc added. Surface work includes anodized aluminum, baking finish, anodizing and these are decorative and increase corrosion resistance.
LinkIconClick here for Aluminum

Q.Does aluminum rust?

A.Aluminum naturally forms a corrosion-resistant oxidized film in air and has excellent self-defense.


Q.Is copper okay in acid rain?

A.Rain that falls in regions with clean air is around Ph 5.6 (Ph 7 is neutral) and rain lower than this value is internationally known as acid rain. According to the Ministry of the Environment rain in Japan is Ph 4.5-5.8. (1988-1992) Copper elution from acid rain suddenly increases around Ph 4 and the peak is at Ph 3.5. However, there is next to know elution at around Ph 5. Further, a study of 48 countries by the corrosion working group in the International Organization for Standardization showed that over 4 years, 1986-9, the average elution in Tokyo was 0.0006mm/year, 0.0023mm/year in Okinawa, and in industrial regions in Europe with high levels of sulfur the highest was 0.0033mm/year. Even with 0.0033mm elution per year it would take 30 years for 0.1mm elution and in Okinawa it would take 43 years, 166 in Tokyo. This shows that there is sufficient protection if an appropriate thickness of sheets is used.
LinkIconClick here for copper sheets and strips

Q.Are there problems with copper thatched roofs?

A.This is not usually a problem but if chemical components or smog dissolves into the air and mixes in the rain and this touches the copper plates then it promotes rapid oxidization. This looks black. However, this oxidized film is extremely thin and is washed off by rain and returns to its regular brown color after 3-6 months.

Q.We are considering using traditional Japanese tiles but how can we avoid holes opening in the areas that touch the tiles?

A.If there is a heavy rain flow and this collects in places with copper roofing the copper can easily elute. This is because the protective film formed from oxidants on the copper surface is easily removed in heavy rain. Further, this phenomenon is thought to speed up when dust clouds strike the roof hard or chemical components in the glaze elute. In particular, the gap between the tiles is higher in traditional Japanese roofing leading to more elution compared to only copper sheet roofing. If this is left alone the oxidants turn yellow and in bad cases this can lead to holes opening. We recommend increasing the thickness of the copper sheets (over 0.5mm) or having double slating from the parts that touch tiles up to the third step.

Q.Do the copper rust/ions affect living things nearby?

A.It used to be mistakenly thought that copper rust was a deadly poison but the Ministry of Welfare recognizes that there is absolutely no affect on everyday life and now there are no articles in textbooks or encyclopedias that say it is a poison. Rather, copper is an important element the blood creates and is a vital material for human life. However, even the slightest amount has an effect on microbes and aquatic life, in particular freshwater fish, as is the case with other metal ions. It is safest to avoid rainwater directly falling from the copper roof into bodies of water, although it does depend on the make-up of the body of water. Further, copper ions have properties of stopping the spread of lice and water from the copper roof flowing into rainwater gutters stops the spread of larva.

Q.The oligodynamic metal action of copper.

A.The botanist Nägeli discovered in 1893 that by mixing a tiny amount of copper compound into water, the result has a surprising antibacterial effect. This is called oligodynamic metal action and also occurs with silver and mercury and is the result of microbes and algae life forms being killed by small appoints of copper ions. This action is used in a wide range of uses and its effect is being increased; copper baskets to stop water contamination in kitchens and domestic waste water, copper overflow sheets to control algae in sewage treatment plants and socks with copper fiber to combat athlete’s foot.
[References: Copper and Hygiene, Revised Copper Roofing Methods Manual, Japan Copper Center Corporation.]

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Q.Is titanium hard and difficult to work?

A.There is no major difference between titanium and stainless steel for working. All stainless steel working methods are possible with titanium. However, titanium has high spring back compared to iron and stainless steel so seaming in straight slating should be made strong to take into account springing.

Q.Titanium stock

A.We have pure titanium KS40 (JIS1). Thickness 0.3mm, width 455mm/914mm, thickness 0.4mm, width 914mm. Type two thickness 1.0mm x width 1219mm x length 2438 mm. We can produce other measurements on order.
LinkIconClick here for Titanium

Q.The durability of titanium

A.The surface of titanium has a film of less than 100Å thickness (Ångströms, 1Å= 10-8cm). This oxidized is extremely stable in many environments. This makes titanium very durable against the atmosphere, sea water and various chemical environments. Titanium is a good corrosion-resistant material that does not corrode in natural environments.

Q.Do you have molded titanium products?

A.We has processed molded in flat seam roofing "hayabuki". There are 6 types: 130, 150, 175, 182, 227 and 250.
LinkIconClick here for "Hayabuki"

Roofing materials

Q.The quality of the material of a roof material

A.Our metal roofing materials are as follows.

Materials for metal roofs

Sakigake Hayabuki Harebare


roof 12


roof 20

Kabeichi Hishibuki
Copper  ○
Copper sulfide   ○
Pre-painted stainless steel  
Pre-painted galvalume steel
Pre-painted galvalume steel(Heat shielding type)      

Q.Flat seam roofing“Sakigake”

.Since “Sakigake” copper were introduced in 1980 they have been used as a copper roofing material in many buildings. Copper plates, previously only available in the world of workmen, became available as a cheap roughing product available to anyone and came to be used throughout Japan. We have copper and copper sulfide as well as pre-painted stainless steel (0.3mm) and coppersoftain (0.3mm).
LinkIconClick here for “Sakigake”.

Q.Flat seam roofing“Hayabuki”

.“Hayabuki” was developed to be quicker and more attractive and can be used with colored stainless steel and colored G L sheets. “Hayabuki” disposes of the problem with previous methods of the ‘grip’ task for joints. By using the cassette method to hang joints, beautiful flat seam roofing can be made for even 0.4mm colored stainless steel – a previously impossible task. Furthermore, anyone can assemble “Hayabuki” simply through reducing the work time with increased productivity and preventing cracks from thermal expansion. We have many materials including copper, copper sulfide, pre-painted stainless steel, coppersoftain, pre-painted galvalume steel and titanium.
LinkIconClick here for “Hayabuki”

Q.Metal roofing for renovation “Harebare”

. “Harebare” are flat seam roofing developed to refurbish flat sheets and create cover roofing with no need to remove the pre-existing flat tiles. This work method makes next to know waste and is an environmentally-friendly, economical construction method that allows you to stay in your home while performing the work. It is extremely light, less than 1/10 of Japanese tiles, at 4.5kg/m2 and adds no strain to the building. “Harebare” are earthquake proof too. The shapes are the same as those for “Hayabuki” and we have 182mm and 227mm standards. The materials we use are pre-painted galvalume steel and pre-painted stainless steel.
LinkIconClick here for “Harebare”

Q.Shadan roof 12

.“Shadanroof 12” uses standard length horizontal roofing materials and is a coverless method with floor-joints rendering joint covers unnecessary. “Shadanroof 12” is fixed by hanging and absorbs thermal expansion horizontally form its open floor joint completely preventing cracking. The main wall and joints have back-up material on the lining preventing cracks during assembly and makes improvements on pre-existing products in soundproofing and thermal conductivity. "Syadanroof12 "roof gradient can be used from more than 14 °. We have lots of materials – copper, copper sulfite, pre-painted stainless steel, coppersoftain and pre-painted galvalume steel .
LinkIconClick here for “Shadanroof 12”

Q.Shadan roof 20

."Shadanroof 20" is a metal roofing material with ventilation and insulation. The standard material is pre-painted galvalume steel (heat shielding type) and thermal insulation of up to 20 degrees can be expected through the ventilated insulating back up material.“Shadanroof 20”uses ventilating arabesques in the eaves (aluminum extruded material). This creates a natural airflow to expel air through the ventilation shaft and stops temperature rises in the summer. The main sheets and joints are more or less the same as “Shadanroof 12” and can be used from more than 14 °. The designability has also been increased with 20mm steps."Shadanroof 20" can also repair work. Renovation of the tile on the plane can be constructed without removal from the existing roof. Moreover aeration method can be easily. “Shadanroof 20”uses pre-painted galvalume steel(heat shielding type) or copper .
LinkIconClick here for “Shadanroof 20”


.“Kabeichi” are flat seam used on walls. The material was developed taking into account designability and ease of work. Each individual tile effectively absorbs thermal expansion and makes working on openings and windows easy.
LinkIconClick here for “Kabeichi”


.“Hishibuki” are seamed individually so there is no need to worry about thermal expansion. We recommend this for parapets and steep sloping roofs.
LinkIconClick here for “Hishibuki”

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