“I turn more intense as I age.”
( Florida Scott-Maxwell )
Copper is one of the most lasting and aesthetically delighting roofing and cladding options available for domestic to bigger commercial and industrial edifices. The Cu forms a protective barrier about it every bit shortly as it reacts to the ambiance. This allows the stuff to better and to stand against the trial of clip.
The purpose of this study is to present the reader to copper as a roofing stuff in the edifice industry. Standing seam Cu roofing and cladding to multi-storey edifices will be the focal point of this study.
3. Why Cu?
Copper is used in the edifice industry because of its lastingness and the easiness of episode and workability. A decently installed Cu roof will outlive other types of roofing systems. Copper is 100 % recyclableand does non lose any quality whether in a natural province or after it was used as a manufactured merchandise. Harmonizing to the Copper Development Association ( CDA. 2010 ) , Cu is one of the most recycled metals, approximately 80 % of the Cu of all time mined is still used in some signifier today.
4. History of Cu roofs
Copper has been a really of import stuff to adult male since ancient times. So much so that one of the chief phases of world ‘s history is named after a Cu metal, bronze-age. Copper and its many metals have had a critical function in many civilisations.
In the Roman period it was mined in Cyprus, this resulted to the metal being named Cyprium, this name was subsequently shortened to Cuprum and finally we know it in English as Cu.
Today, most Cu is mined from unfastened dramatis personae mines around the universe. The Cu is extracted from smelting big sums of Cu ore, before being refined to the Cu we use and know. In the early eighteenth century about 90 % of the universe ‘s Cu was smelted in South Wales ( COPPER Africa. 2010 ) .
Copper has been used as a waterproof roofing stuff since antediluvian times. It can be seen on roofs and domes on today ‘s edifices. It is recognizable by its light-green coloring material. This coloring is because of the ambiance responding with the Cu to organize a protective barrier against corrosion around it. Initially, exposed Copper atoms react with the air to organize the pink oxide, this is called cuprite. This easy oxidizes more to the black oxide, called tenorite. When this black oxide gets wet it reacts with S dioxide and C dioxide from the air to finally organize the patina, which gives it a green gleam.
Technology and improved techniques make Cu the perfect edifice stuff for roofing, cladding and the accoutrements traveling with roofing systems. More and more pre-fabricated Cu merchandises on the market hold reduced the cost and this enabled Cu to be used in more edifices than in the yesteryear.
5. Types of roofing systems.
Copper roofs have been known to last for over 700 old ages ; the infrastructure instead than the Cu itself finally fails. The ductileness and plasticity of Cu allows it to organize over irregular roof signifiers and constructions. Domes and other curved roof forms are a forte when it comes to copper.
New tools and building methods have been introduced that give support to the quick, correct, and cost-efficient installing of Cu roofs.
Types of Cu roofing systems include:
5.1. Standing Seam Roofing
Standing seam, the most common system, roofing consists of pre-fabricated or unmoved formed pans. The Cu pans and are joined together with dual locked standing seams. Copper cleats lock into these seams to repair the roofing to the base construction. This method prevents the pans or sheets from stealing down the roof.
5.2. Batten Seam Roofing
Batten seam roofing consists of Cu pans that runs parallel to the angle of the roof and is separated by wood battings. The battings are so covered with Cu headers that are fixed to the battings. These headers lock the loose pans into next pans.
5.3. Chevron Roofing
A common Chevron roof design is based on normal batten seam building, but secondary battings are fixed to the roof. These excess battings are strictly cosmetic and do non add to the functionality or construction of the roof.
5.4. Flat Seam Roofing
Flat seam roofing systems are by and large used on roofs that are level or have a really low pitch. Flat seam roofing is constructed of rectangular Cu sheets. Two neighboring sides of the sheets are folded over and two are folded under to lock them in topographic point. Copper cleats are so installed seams to do the roof waterproof.
5.5. Horizontal Seam Roofing
Horizontal seam roofs consist of Cu pans that run horizontally across the roof pitch. At each repairing point or inch a measure is used to let neighboring pans to lock successfully.
5.6. Mansard Roofing
A Mansard roof is, based and is really similar to standing seam or secure seam building.
6. Standing Seam Copper Roofing and Cladding
Standing seam, the most common system, roofing consists of pre-fabricated or unmoved formed pans. The pans and are joined together with dual locked standing seams. Copper cleats lock into these seams to repair the roofing to the base construction. This method prevents the pans or sheets from stealing down the roof.
When preformed Cu pans are used, they are joined at the top and lower terminals by slanting seams. In-situ formed pans involve the usage of Cu sheets on axial rotations which are shaped into pans by electrical pan formers. This allows one to organize long, uninterrupted pans, this eliminates the demand for seams, but if this method is used, one must let for enlargement articulations due to the enlargement and contraction belongingss of the Cu.
6.1. General design considerations
6.1.1. High Winds
In countries where high air currents occur, the roof design must be evaluated to do certain the roof can defy the air current forces. High air currents can set great positive or negative force per unit areas on roofs, particularly the borders, so the particularization must guarantee that the roof is unafraid.
6.1.2. Heavy Rain
Where heavy rain is likely, the interior decorator must give allot of idea and attending to the incline, seam inside informations, vales, troughs and downpipes of the roof. The seam highs can be adjusted if it is necessary.
6.1.3. Ice and Snow
In countries where there is allot of ice and snow, the interior decorator should do proviso for the tonss that act on the roof from the weight of the snow or ice. Increasing the incline so that the snow can skid of the roof must be considered.
6.1.4. Temperature Scope
When the temperature fluctuates, the Cu and any next stuffs will spread out and contract in different ways. This should be taken into consideration. This is of import when put ining constituents with possible bounds to motion in one way.
6.1.5. Building Orientation
Consideration should be given to the relationships between the roof and the way air current, rain, and Sun. The issues discussed supra will depend on the orientation of the edifice.
Staining occurs when H2O that was in contact with the Cu runs of and gets absorbed by other stuffs. Staining of the other stuffs can be avoided with good design.
Copper salts form on the surface of a Cu sheet due to the natural weathering of Cu. When these salts are assorted with rain H2O and the H2O run on to other stuffs, it will do the typical green discolorations. To forestall such discolorations, the interior decorator must take all option into consideration to forestall run-off onto other next stuffs. One can utilize a clear, silicon-based coating on cement surfaces to assist protect the surface during the first and most rough weathering of the Cu.
The natural weathering procedure that leads to the green patina to organize on the exposed Cu takes allot of old ages. There are processes available to rush up this procedure.
6.2.1. Types of Cu in the edifice industry
Copper in the edifice industry is 99.9 % pure Cu. There are three different types of Cu used in the edifice industry, viz. :
18.104.22.168. Deoxidized Cu
This is Cu that contains no O. It is used in plumbing applications where welding is required or for technology intents.
22.214.171.124. Fire refined tough pitch Cu
This Cu contains O and is stronger than deoxidized Cu. It has higher thermic and electrical conduction and has a higher opposition to corrosion than deoxidized Cu. This type of Cu is used chiefly for roof and facing applications.
126.96.36.199. Electrolytic tough pitch Cu
This Cu contains fewer drosss than fire refined tough pitch Cu and is used for electrical music directors because of its high.
188.8.131.52. Lead-Coated Copper
Lead-coated Cu is a strong, lightweight, lasting and easy to put in, grey metal finish option of Cu. It does non add to the life of a Cu roof, but it provided another coloring material to architectural Cu applications. In-addition, the grey finish offers a solution to the staining issue. The run-off of this metal is less than that of conventional Cu, and it does n’t stain the other stuffs.
6.2.2. Hardness in Copper Sheets
184.108.40.206. Quarter-hard is defined by its ability to be dead set back onto itself along the grain boundary without interrupting.
220.127.116.11. Half-hard can be dead set 90° .
18.104.22.168. Soft is good for cosmetic applications.
The hardness of the metal determines the application. If your Cu undertaking involves back uping any sort of weight, stick to harder piques.
6.2.3. Cold Rolled Copper Sheets
Copper comes in many signifiers and strengths. It is really of import to stipulate the correct scaling and type of Cu to be used with the specific application. Copper used for a standing seam roofing system comes as a sheet, rolled up in a bobbin, called roofing Cu ( Copalcor ) . The breadth of the sheet is 600mm and comes in thicknesses of 0.50 to 0.70mm.
6.2.4. Corrosion Resistance
Copper does non react to H2O, but it bit by bit reacts with the O in the ambiance. This consequences in a brownish-black Cu oxide sedimentation forming on the surface. This creates a protective bed on the surface that prevents the Cu against extra corrosion. Verdigris, a green bed of Cu carbonate can be seen on aged Cu buildings, like on the Statue of Liberty.
6.2.5. Electrical and Thermal Conductivity
Copper and its metals are first-class music directors of electricity and heat. Copper is the most common of all metals in these applications because of its great belongingss. Copper alloys have less electrical and thermic conduction than pure Cu.
6.2.6. Ease of Fabrication
Copper can be shaped to the needed signifier and dimensions by any of the common fabricating procedures. It is usually rolled, pressed, extruded, forged and formed at high temperatures.
Mechanical fasteners, such as prison guards, bolts, and studs are the simplest connection method. They typically do non necessitate specific tools for installing, and it can be taken apart and be reassembled once more.
Adhesive materials can besides be used in some applications. The strength and dependability of the bond depends on the surface readying, adhesive choice, and the design of the joint.
The three common ways of fall ining Cu and metals are soldering, brazing, and welding. Where a H2O tight seal is required, soldering may be used. Lead or tin-based filler metals are typically used. Soldered articulations typically depend on mechanical fasteners for strength. This method is used for sealing articulations in troughs, roofing, and flashings. Because the filler stuff does non fit Cu in coloring material, soldering should merely be used in concealed articulations.
Brazing is the most preferable method for fall ining Cu pipes and tubings. Colour matching is a job once more.
The concluding metallurgical connection method, welding, is rarely used with Cu. Welding uses high temperature or force per unit area to blend the metals together.
There are three generic classs of coatings for Cu metals.
22.214.171.124. Mechanical interventions
Mechanical interventions are coatings that are typically applied at the store by mechanical agencies. They normally affect merely the surface of the Cu. There are five standard mechanical designated coatings:
* As Fabricated:
This is the coating after its production procedure, such as peal, bulge, or casting.
Polishing the Cu to a smooth, mirror-like visual aspect. This is the brightest mechanical coating available.
* Directional Textured:
Wheel or belt smoothing with all right sums is required for this coating and consequences in a uninterrupted form of really all right, about parallel abrasions.
* Non-directional Textured:
This matte coating is chiefly used on castings. The Cu is normally sandblasted to accomplish a certain grade of raggedness.
A procedure in which a Cu metal sheet is pressed between two axial rotations to bring forth a form.
126.96.36.199. Chemical interventions
6.3.1. Surface Preparation
The surface readying is the same for all Cu roofing systems. The surface must be dry, smooth and free from any crisp borders or objects like nails or prison guards.
6.3.2. Supporting Substrate
Standing seam roofing and facing requires the installing of a backup infrastructure that support the Cu coating bed,
This substrate normally consists of 20 – 22mm S.A.P lingua and grooved get oning fixed to the chief construction. However, any substrate can be installed, every bit long as the Cu has the necessary support. Other endorsing options include:
This decking can be fixed to any chief construction like steel or concrete. The design must, nevertheless, supply for the installing and repair of the wood substrate.
6.3.3. Fastening the pans to the substrate
There are three ways of repairing the Cu sheets to the substrate viz. :
This is the most often used repair method, because it allows the Cu to travel, because of enlargement and compaction under different temperatures. Cleating minimizes the potency for clasping. The cleats are normally spaced at a lower limit of 600mm Centres to center and are fixed to the infrastructure with 2.8 tens 22 mm Cu clout-headed nails.
Nails are used to repair the cleats to the substrate or in particular instances where no motion is wanted, normally at base flashing or at eave strips. Merely one border of a strip should be nailed, to let motion at the other terminal of the stip. All nails should be flathead, wire slate nails made from difficult Cu, brass, or bronze.
188.8.131.52. Sleep togethering
This method is used where the Cu must be held in topographic point, such as at a ridge cap in countries with high air currents. It is besides used to procure Cu to brickwork. Screws must hold a broad or large caput to forestall the prison guard from cutting into the Cu. Lead washers may be used for extra protection. Where the prison guard must be H2O tight, a little Cu cap is soldered over the screw caput.
All fasteners must be of Cu or Cu metals to forestall the different stuffs to respond with each other and rush up the corrosion procedure.
6.3.4. Roofing Felt
The full surface should be covered with an recognized and decently specified underlay stuff secured to the adorning with Cu clout nails. The carpet pad, which is normally soaked roofing felt, acts as a pillow, every bit good as supplying impermanent conditions protection for the roof deck.
A sheet of constructing paper must be applied over the felt. Some roofing felt contains tarmac and, because Cu behavior heat, the lifting temperatures can do the tarmac to run and bond the Cu to the roofing felt. This restricts the motion of the Cu roof and can ensue in the failure of the system. The edifice paper acts as a slip sheet to forestall such bonding.
6.4. Equipment and Tools
6.4.1. Pan formers and seamers
A broad choice of power pan formers and power seamers are available to assist with the building of Cu roofs. Power pan formers can take level sheets of Cu and do standing seam roofing pans on site. The machines form high quality, consistent pans in any length. The length is merely limited by the contractor ‘s ability to transport and manage the stuff. Pan formers can work with assorted sheet breadths and can do pans with changing seam highs. The standing seam is typically 150mm high.
Power seamers are used to bring forth finished standing or batten seams. The seamers clamp onto the sheet of Cu and so impel themselves under electrical power to organize the seam. They can organize seams of about any length.
6.4.2. Panel swerving machine
This machine allows the contractor to swerve the panels to any radius. Convex or concave signifiers can be curved.
6.4.3. Gutter organizing machine
This machine allows the contractor to do troughs on site and put in them in feasible lengths or subdivisions.
6.5. Construction and Detailing
This birds-eye position of a standing seam Cu roof shows the basic construct.
Standing seam roofing consists of pre-fabricated or unmoved formed pans. Copper cleats lock into these seams to repair the roofing to the base construction. This method prevents the pans or sheets from stealing down the roof.
0.6 mm Copper sheeting with a breadth of 600 millimeter is used to organize the pans. The terminal merchandise is pans of 510 millimeters broad that is joined by organizing a 30 millimeter two-base hit welded standing seam as shown below.
6.5.2. The Standing Seam System
6.5.3. Detail at Parapet Wall
A Cu header is attached to the higher border of Cu siding utilizing a individual lock seam. This screen extends over the parapet and is fixed into a uninterrupted lock strip that is on the back side of the parapet wall.
6.5.4. Stepped Flashing Detail
Stepped flashing is used where a aslant roof meets a masonry wall. A typical illustration is where a brick chimney rises above a roof. The inside informations shown dressed ore on such chimney flashings, but apply to other state of affairss as good.
There are two ways of put ining stepped flashings. One type uses pieces of Cu base blinking installed with each class of herpes zosters.
The 2nd, most common type uses a individual Cu smuggler under the roof covering. This smuggler is attached before the roofing stuff is installed. The roof part of this smuggler flashing has a hooked border and is cleated at 300 millimeter c.c. The base flashing is extended up the wall a lower limit of 170 millimeters ( two bricks ) . This requires the cap flashing to be in two pieces, a flashing and a counter flashing.
This stepped flashing is used on the two sloped sides of the chimney. The lower sides are flashed with a Cu apron that covers the roof covering.
6.5.5. Detail at Valley
This item shows an option for deciding the sealing at a vale of a standing seam roof. The Cu roofing overlaps the vale blinking a lower limit of 150mm and is folded and fixed into a uninterrupted Cu strip. The locking strip is soldered to the vale flashing.
An alternate option is to utilize a dual crease in the vale flashing, as a replacing for of a locking strip. Both methods are shown.
6.5.6. Detail at Hip
This item shows a standing seam of a Cu hip roof. This method allows the standing seam to be hidden by a ridge cap which allows for both a clean frontage and conditions tight seal.
6.5.7. Detail at Gutter
The item shows the recommended method for the installing of a trough with Cu roofs.
A Cu trough is supported by a brass bracket. The upper border of the trough extends at least 150 millimeter onto the roof and is folded over and held by cleats at 300 millimeter c.c.
Copper braces at 750 millimeter Centres can be placed at the mid-points between brackets.
If the trough breadth is more than 150 millimeter or in countries with ice and snow, brass straps should besides be used to increase the strength of the trough. These must widen at least 150 millimeter onto the roof. The country around prison guards and the strap must be soldered to guarantee H2O stringency.
6.5.8. Detail at Ridge
Two options of detailing a ridge are shown. The seams are laid to overlap a lower limit of 150 millimeter from the ridge.
InDetail 1, a Cu ridge cap is used to repair the standing seams along the ridge. The ridge cap is locked into the top borders of the Cu pans. This allows for enlargement and contraction.
InDetail 2, the ridge is created by a wood batting that is cladded with a Cu cap.
12.1.1. Detail at Gable
12.1.2. Expansion Great attention must be given to the contraction and the enlargement of Cu due to the thermic features of the stuff. Detail should ever let for enlargement and contraction.
Because of Cu ‘s long life as a edifice stuff it is exposed to long term pollutants or soil. The chief job of cleaning Cu roofing is that you can for good stain or damage the Cu. The cleaning methods of Cu have been perfected over many old ages.
6.6.1. To take crusty soil sedimentations
The most common cleansing method is to blow the surface with Walnut shell dust at a force per unit area of about 2 – 3 saloon. This forces the soil crust to raise off the surface without damaging the Cu.
6.6.2. To clean unevenly patinated Cu:
Use a sponge to clean the Cu. Use a mixture of six parts concentrated phosphorous acid to one portion concentrated azotic acid diluted by 50 per centum distilled H2O.
Leave the acerb solution on the Cu for one minute. After the minute wash the roof once more with a sponge soaked in Na hydrogen carbonate solution. Rinse of all the acid with fresh H2O afterwards.
Then you apply ammonium oxalate as a 2nd neutralizer to even out any remains left by the first neutralizer. Rinse off with fresh H2O afterwards and pass over the cleaned Cu with a clean cotton fabric until no coloring material shows on the fabric. Wipe the surface once more with a fabric soaked with mineral liquors until no coloring material shows on the fabric.
Use a thin coat of carnauba wax. When the wax wears off, the Cu will get down its repatination once more.
This process can be used when you replace subdivisions of a patinated Cu roof or when you do an add-on to an bing Cu roof. Treating the bing Cu roof will allow the new add-on patinate together with the bing roof, ensuing in an even coloring material for both the old and the new roofs.
When people think about put ining a new roof, Cu is non a stuff that usually comes to mind. Nevertheless, Cu has been used on roofs for centuries.
The one large disadvantage of Cu in South-Africa is that it is expensive and that Cu is a stuff that is stolen and sold for money all around the state.
Copper is a good roofing option and there are many locally available makers. One of the biggest providers of Cu merchandises is Copalcor.
“Copalcor offers solutions integrating a broad scope of rolled, extruded and forged non-ferrous metal merchandises for the local and international market. Through ongoing development and enlargement the company maintains its place as a leader in the field of service to South African strategic industries and continues to turn as an exporter worldwide”
( Copalcor, 2010 )
Copper roofing is a really specialised industry and hence there is non such a broad assortment of Cu roofing contractors available in South-Africa. A few makers and contactors are:
Clotan Steel ( Pty ) Ltd.
Global Roofing Solutions ( Pty ) Ltd.
Copper is a really expensive edifice stuff. Because Cu roofs are really expensive compared to conventional tile roofs, the demand of Cu roofs is non so high in South-Africa. Copper is considered a specialised roof and is hence a specialised building, this makes Cu roofing expensive.
If you consider that a Cu roof will outlive about any other roof and that Cu is 100 % reclaimable, it will be a good investing or add-on to any edifice. It requires about no care that keeps the cost down.
The initial cost for the building and installing of a Cu roof is high but the advantages over shadow the monetary value of the roof.
9. Case survey
9.1. Freedom Park //hapo Museum
Location: Capital of south africa, South-Africa
Architect: Office of Collaborative Architects
GAPP Architects / Urban Designers ; Mashabane Rose Associates ; MMA Architects, Johannesburg, South Africa
Design Architect: Jeremy Rose
Undertaking Architect: Dieter Brandt
9.1.1. Undertaking Description
The vision for //hapo ( the dream ) , an interpretative Centre and Pan-African archive, was to supply an synergistic exhibition infinite which would convey the history of South Africa over 3.6 billion old ages.
The facade of the edifice is wholly clothed with Cu sheeting. Frans du Toit, pull offing manager of Cupric Tectronics, said that Freedom Park is the first copper-clad edifice of its size in South Africa.
“Installing the roof sheeting was disputing because there are so many elaborate design elements, ” says du Toit. “We used a specialized machine that rolled the Cu into long, consecutive sheets that were placed straight onto the building.”
The contractor had to alter their normal installing methods to accommodate the specific demands of the design. Because there are about no consecutive lines, the installing had some grade of trouble.
Copper, which fades over clip and is already demoing seeable color differences on the frontage of Freedom Park, was chosen for a figure of grounds. Dieter Brandt says that: “Copper is an African resource, ” “The thought is that the stuff will age over clip and the patina gives a sense of antiquity. We wanted a stuff with monochromatic feel and we needed a stuff to intermix in with the brickwork that is typical to Salvokop rail small town. The metaphor of bowlders is enhanced by the varying phases at which the weathering of each copper-clad bowlder that is exposed to predominating conditions takes topographic point, ” says Brandt.
The specializers in Cu roofing and facing, Cupric Tectonics, used 70 metric tons of Cu on the roof and side facing of the edifice. The 0.6 millimeter Cu sheets was profiled and installed on site, straight on the edifice. Over 9000 M2 of country was covered with Cu supplied by Copalcor. The stuff is 99 % pure phosphoric deoxidized Cu metal. ( ASTM B152C 12200 half difficult Cu ) . A squad of 16 good trained specializers worked on the undertaking to finish the Cu installings to the edifice. This was done to guarantee that the long pans did non flex out of form before it could be installed. The Cu forms a natural moving ridge like expression, besides known as “oil canning” .
A province of the art Schlebach manufactured Quadro and profile machine was used to organize the pans of the edifice. The machine was placed on the staging so that the pans could be placed straight on the edifice for installing.
The method used to put in the Cu to the edifice is called dual standing seam system. This system is based on concealed repairing which means that there is no repairing through the sheets guaranting a H2O tight seal that will last for many old ages
Due to the size of the edifice and because the Cu pans are formed on site, big pans could be made and fitted straight onto the edifice. On site, pans are formed by utilizing Cu in level sheets on axial rotations which are dead set into pans by electrical pan formers. Long pans can be made that eliminates the demand for cross seams.
Long Pan building inside informations are designed to suit for the motion as a consequence of the enlargement and contraction over long spans of Cu sheets. The points of emphasis alleviation are typically accommodated at eaves, cross articulations ( if any ) , and ridge and base conditions by guaranting that the Cu sheet is provided with proper clearances and is secured by enlargement fastener devices that will non blockade thermal
Particular edifice kineticss should be considered before specific Cu inside informations are designed. Constructing enlargement articulations must be accommodated and decently detailed. Besides, constructing orientation should be taken into consideration. A north sloping roof, for illustration, will derive more heat than a south sloping roof.
All roof incursions should let for enlargement in the same sums as the roof panels, nothingnesss or infinites should be filled with loose insularity or compressible joint filler
Copper has been use as a roofing stuff since antediluvian times. Technology and improved techniques make Cu the perfect edifice stuff for roofing, cladding and the accoutrements traveling with roofing systems. More and more pre-fabricated Cu merchandises on the market hold reduced the cost and this enabled Cu to be used in more edifices than in the yesteryear.
Standing Seam Construction offers many advantages. The greatest advantages are that it creates a H2O tight seal because of no sheets are penetrated with hidden repair and this allows for fast building that reduces labour costs. Copper Standing Seam building is a long lasting roof building with a life clip of altering aesthetics.