VPAU592 Construction Materials For Building Projects

Copper and Aluminium

COPPERArchitecture / Industry

• Copper has been used as a waterproof roofing material since ancient times, giving many old buildings their greenish roofs and domes. Initially copper oxide forms, replaced by cuprous and cupric sulfide, and finally by copper carbonate. The final carbonate patina (termed verdigris) is highly resistant to corrosion.

COPPERArchitecture / Industry

• The statue of Liberty contains 81.3 tonnes of copper.

• Copper alloyed with nickel (Cupronickel and Monel) is used as corrosive resistant materials in shipbuilding.

• Copper compounds in liquid form are used as a wood preservative, particularly in treating original portion of structures during restoration of damaged due to dry rot.

COPPERArchitecture / Industry

• Copper nails were used in making oast cowls

• Copper wires may be placed over non-conductive roofing materials to discourage the growth of moss (Zinc may also be used for this purpose).

COPPERHousehold Products

Copper is still commonly used for household products. These include:

• Copper plumbing fittings and compression tubes.

• Door knobs and other fixtures in houses.

• Roofing, guttering and rainspouts on buildings.

• Copper water heating cylinders.

COPPERDurability

Sheet materials like stainless steel, copper, zinc, aluminium and lead are inherently durable. The oxidisation of the base material forms a protective patina.

Usually used for flashing or very small sections like covered entry ways, copper is expensive.

COPPERRecyclable

Copper is used for regenerative principles of sustainable design. If a building were to ever by dismantled, the copper would be reused because of its high value and variety of possible uses

COPPERThe Future

• While copper is much sought after for heritage projects and feature roofs on expensive homes, it is slowly making it'd way into the average residential sector.

• Many companies are now selling interlocking shingle type copper products.

• Roofing companies that do standing seam roof in other metals also offer copper as an option,

COPPERAdvantages

• Copper is durable. A well designed and fixed copper roof will easily last the lifetime of it's owners or their children.

• It fire resistant. • At the correct roof slope it will shed snow very easily. • It is lightweight and so does not impose dead loads on the

roof framing. • There is no limit the angle of pitch of a copper roof.

COPPERDisadvantages

• Installing copper roofing is not a job for an amateur. It has to be done correctly. You cannot cut costs by doing it yourself.

• Copper is more expensive than most other roofing materials. • A skilled professional copper roofer will know how to install

your roof taking into consideration galvanic corrosion, but as for all metal roofs the owner should make sure that other people working on the roof at a later date, know the correct

methods.

ALUMINIUMBrief

Aluminium is a soft, durable, lightweight, malleable metal with appearance ranging from a silvery to dull grey, depending on the surface roughness.

Aluminium is non-magnetic and non-sparking. It is also insoluble in alcohol, though it can be soluble in water in certain forms.

ALUMINIUMBrief Continued…

• It is mostly used as a non-ferrous metal.• Global production of aluminium in 2005 was 31.9 million

tonnes. It exceeded that of any other metal except iron (837.5 million tonnes).

ALUMINIUMPure Aluminium

• Relatively pure aluminium is encountered only when corrosion resistance and/or workability is more important than strength or hardness.

• A thin layer of aluminium can be deposited onto a flat surface to form optical coatings and mirrors.

ALUMINIUMPure Aluminium Cont…

• Pure aluminium has a low tensile strength, but when combined with thermo-mechanical processing, aluminium alloys display a marked improvement in mechanical properties, especially when tempered.

• a fresh, pure aluminium film serves as a good reflector (approx. 92%) of visible light and an excellent reflector (as much as 98%) of medium and far infrared.

ALUMINIUMAlloys

• Aluminium readily forms alloys with many elements such as copper, zinc, magnesium and silicon.

• Almost all bulk metal materials that are referred to as aluminium are actually alloys.

• For example, the common aluminium foils are alloys of 92% to 99% aluminium.

ALUMINIUMUses

Transportation:• Automobiles, aircraft and bicycles.Construction:• Windows, doors, siding, building wire,

etc.Aluminium is widely used in watch

production as it provides durability and resists tarnishing and corrosion.

Packaging:• Cans, foils, etc.

ALUMINIUMThermal Resistance

• The thermal resistance for aluminium frames is poor.

• Modern aluminium window frames typically consist of two surfaces separated by a thermal break made of an insulating spacer material.

• While this can double thermal resistance, it is still less than half that of other frames.

ALUMINIUMStability / Durability

• Compared to wood, vinyl or PVC, aluminium is superior alongside fibreglass.

• Metal window frames durability depends on the geographic location, eg, in coastal areas the effect of Potassium nitrate form the salt will quickly damage aluminium.

ALUMINIUMAdvantages

• Is durable• Requires minimal maintenance• Is fire-resistant• Is recyclable• Can be very cost-effective• It resists rot• It resists bugs• Doesn’t rust• Strong in compression and tension

ALUMINIUMDisadvantages

• Poor insulation qualities• Is a non-renewable resource• More expensive than PVCu• More difficult to source