Norwalk, Ct
INTRODUCTION TO ROOFING A typical roof begins with a framework of rafters that supports a roof deck consisting of sheathing and underlayment. The roof deck, in turn provides a nailing base for the roof surface material. THE ROOF DECK Though the type of roof deck used can vary depending on the roof surface material, most decks have both sheathing and underlayment. Sheathing, the material that provides the nailing base for the roof surface material, ranges from solid plywood to fiberboard to open sheathing which is used with wood shingles. Sandwiched between the sheathing and the surface material is the underlayment, usually roofing felt. A heavy, fibrous black paper saturated with asphalt, roofing felt is waterproof enough to resist water penetration from outside, yet porous enough to allow moisture from inside the attic to escape. THE ROOF SURFACE The material on the roof must be able to withstand wind, rain, snow, hail, and sun and protect the house from these elements. Because roofing varies widely in size, shape, material, a wide variety of roof surface materials is available. Traditional sloping roofs are usually covered with overlapping layers of asphalt shingles, wood shingles or shakes, or tile. Of course you can also you slate, aluminum, or galvanized steel. Flat or low-sloping roofs are most often surfaced with alternating layers of roofing felt and asphalt or tar, with a layer of gravel on top. These are known as built-up, or tar-and-gravel, roofs. Some flat roofs are covered with insulating polyurethane foam or a rubber-like modified bitumen membrane. The surface of the roof is often broken by angles and protrusions, all of which require weatherproofing – usually provided by flashing. Made from malleable metal or plastic, flashing appears as the drip edge along the eaves of a roof, the collars around ventilation and plumbing pipes, the valleys between two roof planes, and the “steps” along a chimney. Less obvious flashing also protects other breaks in the roof, such as skylights. At the roof edges, gutters catch water runoff and channel it to the ground via the downspouts, which direct water away from the house. A. Asphalt Shingles B. Built-Up Roof C. EPDM Rubber D. Modified Bitumen E. PIB (Polyisobutylene) F. Sprayed Polyurethane Foam (SPF) G. TPO (Thermoplastic Olefin) Asphalt shingles are currently the most popular type of residential roof material for a variety of reasons. They are relatively inexpensive, starting at around $0.80 per square foot installed and go up from there. Things that determine cost are geographical location, slope of the roof, height of the building, ease of access to the premises, complexity of the project, the particular type of shingle and numerous other factors. Because shingles are small, self-contained units, they are easily replaced without disrupting the rest of the roof. They come in a variety of colors and styles, are fairly durable (some have been tested and have achieved a class IV hail rating - the highest available!), and can be easily repaired and maintained. WHAT ARE THEY? Asphalt shingles come in two basic types: glass fiber (a.k.a. fiber glass) and organic. Organic shingles consist of an organic felt material which is generally paper saturated with asphalt to make it waterproof. A top coating of adhesive asphalt is then applied and the ceramic granules are then embedded. Organic shingles contain around 40% more asphalt per square (100 sq. ft.) than their glass fiber counterpart which makes them weigh more and gives them excellent durability and blow-off resistance. Glass fiber shingles have a glass fiber reinforcing mat manufactured to the shape of the shingle. This mat is then coated with asphalt which contains mineral fillers. The glass fiber mat is not waterproof by itself. It's purpose is for reinforcement. What makes the glass fiber shingle waterproof is the asphalt. However, the asphalt itself will not stick to the mat. For this reason, "fillers" are used. The fillers in the asphalt cling to the glass fibers in the mat. The asphalt then encapsulates the glass fibers, fills all of the little holes and voids in the mat rendering it waterproof. After this cools a bit, an adhesive asphalt is used to cover the mat and the ceramic granules are then embedded. The ceraminc granules are there for two reasons. The primary reason is to protect the shingles from the sun. The sun's UV rays are very damaging to asphalt and cause it to deteriorate prematurely. This is one of the same reasons that gravel is used on built-up roofs. The second and more obvious reason for the granules is aesthetics. Asphalt shingles are available in a wide variety of colors to match almost any facade or landscape. So which type is better? By far, the more popular shingles are the glass fiber ones. This may be attributed to the fact that they are cheaper and easier to manufacturer than organic shingles making them more cost effective to the homeowner, or it may be that they are easier to work with. HOW LONG DO THEY LAST? The lifespan of asphalt shingles depends highly upon the environment. Shingles in cooler climates such as the northern United States seem to last longer than those installed in the warmer climates. Studies have shown that the average lifespan for a 20 year shingle in Phoenix, Arizona is around 14 years. In Minneapolis, Minnesota the lifespan was 19.5 years. And in Reading, Pennsylvania, the lifespan was 20.8 years. From this data it seems obvious that the hotter the environment is, the shorter the service life of the shingles. One thing that's very damaging to shingles is Thermal Shock. Thermal Shock is what roofing materials experience when the ambient temperature changes dramatically within a very short period of time - usually 24 hours. For example, in Yreka, California, the temperatures during a summer day can often reach 100 degrees and at night, they'll often drop below 50, sometimes as low as 40. Roofing materials are unable to expand and contract to accommodate such a dramatic temperature change in such a short period of time so cracks and splits in the materials start occurring. Water can then enter the materials and damage them further in two ways. One is the damage water does to asphalt materials in general. It's not that water hurts asphalt, but algae and fungus do and the continuous presence of water will permit algae and fungus to grow on asphalt materials. Another way water damages is the freeze-thaw cycle. In the cold months, water will get into the cracks and then freeze at night. Water expands as it freezes so the more this occurs, the bigger the cracks or splits become. This is why most roofing contractors and consultants are such big advocates of sloped roofs. The better the roofs shed water, the less problems it will usually experience. Still another factor affecting asphalt shingle roofs is attic ventilation. Proper roof ventilation has been known to extend the service life of a roof. Whether it is because it has a direct effect on the shingle themselves or on the other components such as the roof deck is uncertain. For more information on attic ventilation, click here. WHAT ABOUT SHINGLE WARRANTIES?Shingle manufacturers provide product warranties against manufacturing defects ranging from twenty (20) to forty (40) years. The warranties will cover defects such as thermal splitting, some cases of granule loss, cupping, and curling. It is very important that you ask for and receive a copy of the manufacturer's written material warranty before making a decision on whose material you'd like to use. Warranties are generally for materials only. Labor is rarely included so if your roof materials fail, you'll have to pay a roofer to install the new shingles. Warranties rarely, if ever, cover what are known as "incidental and consequential" damages resulting from material failure. "Incidental and consequential" damages are those that occur to the interior of the building. If anything on the inside of the building gets damaged, you or your insurance company will have to pay for it. Warranties are also commonly prorated and non-transferable. This means that if you have twenty year shingles and they fail after ten years, you'll be reimbursed for half the cost of the materials. Non-transferable means that if you sell your house, the warranty will be voided. Some shingle manufacturers are offering NDL (No Dollar Limit) warranties for added costs of around 4.5 cents to 6.5 cents per square foot. These warranties may or may not cover all damages and labor costs. Shingle manufacturers will not warrant their products against "Acts of God or Nature" such as hurricanes, hail storms, severe winds usually in excess of 50 mph, tornadoes, earthquakes, etc. Nor will shingle manufacturers honor their material warranty if the products are improperly installed, if there is improper roof ventilation, if there is equipment installation or structural changes after roof completion, or if there is heavy foot traffic on or over the roof. SHINGLE PROBLEMS • Shingle Failure • Cupping • Splice Types of asphalt shingles include, but are not limited to: • No Cut Out Shingle • "T"-Lock or Interlocking Shingle • Angle-Lap Shingle • Many specialty shingles such as those imitating the appearance of cedar and slate roofing. Built-Up Roof: a roof consisting of multiple plies of roof felts laminated together with bitumen. Built-up roof material can consist of bitumen-saturated felt, coated felt, polyester felt or other fabrics. A surfacing is generally applied and can be asphalt, aggregate (gravel or slag), emulsion or a granule-surfaced cap sheet. Built-Up Roofing is one of the oldest and most reliable ways of installing a new roof. It was first known as composition roofing and started in the 1840's. B.U.R.’s come in two basic types, asphalt and coal tar, and three basic components:
There are many different types of materials used in Built-Up Roofing. Some of these are: BASE SHEETS Asphalt-Coated Organic Base Sheet – Perforated and Non-Perforated Asphalt-Coated Glass Fiber Base Sheet Asphalt-Coated Glass Fiber Venting Base Sheet, Types I and II FELTS AND FABRICSAsphalt-Saturated Organic Felt – Types I (A.K.A. No. 15) and II (A.K.A. No. 30) Coal Tar-Saturated Organic Felt Smooth-Surfaced Asphalt Roll Roofing – Types I, II, III, and IV Asphalt- or Coal Tar-Saturated Cotton Fabrics Asphalt- or Coal Tar-Saturated Woven B.U.R.lap Fabrics Asphalt-Impregnated Glass Felt – Types III, IV, and VI Coal Tar-Impregnated Glass Felt – Type I Thermoplastic Fabrics for Built-Up Roofing – Types I, II, III, and IV BITUMENS Asphalt – Types I, II, III, and IV Coal Tar – Types I, II, and III Lap Cement – A.K.A. Cold-Applied Liquid Adhesive, A.K.A. Solvent Based (Cutback) Asphalt – Type I (Grades 1 and 2), and Types II and III SURFACINGSMineral Aggregate – Gravel or Slag Asphalt Roof Coatings – Asbestos and Non-Asbestos Aluminum-Pigmented Asphalt Roof Coatings – Non-Fibered, Asbestos Fibered, and Fibered without Asbestos Emulsified Asphalt – Fibered and Non-Fibered Mineral-Surfaced Asphalt Roll Roofing (Organic) Mineral-Surfaced Asphalt Roll Roofing (Glass Felt) Other items not listed are flashing materials, mastics, caulking material, fasteners, and roof insulation, to name a few. Now that you see the wide variety of materials available, you are probably wondering what the differences are. The difference in the base sheets is simple. Venting base sheets are specially-designed for use with moisture-cured substrates such as light weight insulating concrete or poured gypsum. Neither of which you homeowners will have to worry about. Regular base sheets are generally used with nailable decks such as plywood. The differences in the felts are determined by the types of reinforcement materials used. For instance, polyester felts are stronger than fiber glass felts which are stronger than organic felts. The fiber glass felts will vary among themselves in quality with Type III being the lowest quality and Type VI being the highest. Gravel or slag surfacings are probably the most popular. The next most popular surfacings are probably the granule-surfaced cap sheets, commonly called 90 pound because they used to weigh approximately that much per square. Now they weigh around 72 pounds per square. Then come the emulsions which can be spray, brush, or roller applied. Now we’ll talk about how B.U.R.’s are put together. Base sheets are usually the first piece of Built-Up Roofing material installed and are usually mechanically-fastened (nailed) to the deck or substrate. Then come the felts. These can be installed with either hot asphalt or coal tar, or cold-applied liquid adhesive, a.k.a. solvent-based asphalt or "cutback" asphalt. Approximately twenty-five to thirty pounds of hot asphalt or twenty to twenty-five pounds of coal tar per 100 square feet (roof square) is used between each ply. Three to five gallons of the cold-applied adhesive is used per square. Last is the surfacing. With a cap sheet, the same amount of bitumen or lap cement is used to install the cap sheet as is used to install the plies. With gravel or slag, a flood coat of about sixty pounds per square of asphalt or seventy pounds per square of coal tar is applied and 400 – 500 pounds per square of gravel or 300 – 400 pounds per square of slag is embedded. Emulsion surfacings will vary. Usually it’s around three gallons per square that is used. If emulsion is what is preferred, an aluminum reflective coating should be applied after the emulsion cures to help reflect damaging UV rays. Built-up roofs can be installed over just about any type of roof deck as long as the proper substrate is used. BUR's can't be mopped to awood roof deck. In this case a rosin sheet and base sheet are needed first. With steel roof decks, the thickness of the deck should be a minimum of 22 gauge and some type of approved insulation should be mechanically-attached to the deck to provide a substrate. Manufacturers should be consulted before mopping to Polyisocyanurate ("iso" for short) insulation. Many manufacturers will not warrant a roof if the felts are mopped directly to the iso and a coverboard such as wood fiber or perlite is needed. In some cases adhesives are being used to attach the insulation to the deck but be sure the roofing materials manufacturer is consulted before this is done. Withstructural concrete roof decks, the roof is often mopped directly to the deck after it's cleaned. Sometimes a thermal insulation is used to provide a substrate. Thermal insulation can be attached by mechanical means, adhesives, or even hot-mopped. If the insulation is hot-mopped with bitumen, then care needs to be taken so as not to allow the bitumen access to the interior of the building at joints in the roof deck. Also, if Isocyanurate insulation is used, only 4' X 4' sheets can be mopped due to its propensity to warp and curl. Withlightweight insulating concrete, pre-cast gypsum panels, or poured gypsum, venting base sheets are attached with special fasteners and then insulation may or may not be installed over the base sheet and then the roof membrane installed. In some cases a vapor barrier will be necessary. Built-up roofs cannot be mopped directly to lighweight insulation or gypsum. Cement fiber roof decks should have a base sheet or insulation mechanically-attached to it before installing the roof. Insulation should be installed in two layers with all joints offset and staggered a minimum of twelve inches. The service life of a roof is dependent on many factors: geographical location & weather conditions, foot traffic, materials used, conditions under which the roof was installed, slope of roof, type of surfacing material, etc. Under ideal conditions, a 3-ply built-up roof should last at least fifteen years, a 4-ply should last at least 20 years, and a 5-ply should last at least 25 years. This author has seen ten year old 4-ply roof that needed to be replaced and twenty year old 3-ply roofs that were still functioning. EPDM: Ethylene Propylene Diene Monomer (or Terpolymer which is simply a product consisting of three distinct monomers). EPDM is classified as a Thermoset material which means it is either fully-cured prior to being installed or that it cures during natural weathering after installation. EPDM roofs are single-ply membranes meaning there is only one ply of roofing material, not multiple plies laminated together. EPDM has been in use on roofs in the USA since the 1960's and is one of the most common types of low-slope roofing materials. This is because it is relatively inexpensive, simple to install, and fairly clean to work with when compared to conventional built-up roofs. There aren't the odors and fumes that accompany built-up roofs which appeals to many property owners and managers. EPDM is a rubber material whose principal components consist of the compounds ethylene and propylene. A flexible rubber matrix forms when a small amount of diene is added to the mix. EPDM is available reinforced or unreinforced with both commonly used; it's also available in either a cured (vulcanized) or uncured (non-vulcanized) state. Vulcanized EPDM is the most common with non-vulcanized often used for flashing purposes. EPDM membrane thickness ranges from thirty mils (0.030") to one-hundred mils (0.100") with the most common thicknesses being forty-five mils (0.045") and sixty mils (0.060"). There are three standard application procedures: (1) fully-adhered; (2) mechanically-fastened; (3) loose-laid. Fully-adhered EPDM uses water or solvent-based adhesives to adhere the rubber to the substrate. Mechanically-fastened EPDM is attached by manufacturer-approved mechanical means to the substrate, and loose-laid membranes are secured only at the perimeters and any penetrations. A ballast of round river rock or concrete pavers is used to hold the materials in place. River rock is usually installed at a rate of 1000 - 1200 pounds per roof square (100 square feet) and the pavers generally weigh approximately 20 pounds per square foot. Structural integrity is important with loose-laid roof systems. The seams of all systems are then sealed using either an adhesive or a splice tape. Splice tapes have tested with a higher tear-strength.
Modified Bitumen (MB) is asphalt that has had modifiers added to it to give it plastic or rubber-like properties. The most common types of modifiers being used are APP (Atactic Polypropylene) and SBS (Styrene Butadiene Styrene). Rolls of modified bitumen membrane come in widths of 36" (0.9 m) to approximately 39" (1 m) and cover an area of approximately 100 square feet to 112 square feet. Surfacings for these roll materials consist of mineral granules, aluminum, copper, or an aggregate such as gravel or slag. Modified Bitumen roof systems consist of one, two, or three ply systems. The type of substrate will often determine the type of system being installed. Modified membranes can also be installed in conjunction with built-up roof materials (such as multiple plies of fiberglass felt) to form a hybrid roof system. Modifieds have proven performance on residential, commercial, and industrial applications. We recommend that all modified roofs be installed on slopes not less than 1/4" per horizontal foot in order to achieve positive drainage. APP MODIFIEDSIn order to create roofing grade asphalt, asphalt flux is air-blown at elevated temperatures which converts the flux to roofing grade asphalt. In the early 1970’s, the Italians, lacking the blowing equipment, were looking for a product that would convert asphalt flux into a usable roofing product. They discovered that if Atactic Polypropylene (APP) - a by-product of propylene polymerization - was added to asphalt then it gave the asphalt some plastic properties. They found that by adding about 30% of APP modifier, they could stretch the modified asphalt up to fifty percent of its original length before it would break. Next came the need to make it into a usable roll product. Some type of reinforcement would be needed. They looked into various reinforcement materials and decided on a polyester mat because polyester would accommodate the APP modified asphalt’s elongation properties whereas the more commonly used woven glass mats would not. The reinforcement material is dipped into the hot modified bitumen mix, then goes through a rolling cylinder, cooled, and then wound into a roll. APP membranes are applied using a torch. The back of the sheet has extra asphalt on it which, when heated, bonds to the substrate. This was especially convenient for the smaller, more cut up roofs because less room and equipment is needed on site to torch-apply a membrane than is necessary for application using hot bitumen. SBS MODIFIEDS While APP was being looked into in southern Europe, northern Europe was experimenting with a different type of modifier called Styrene Butadiene Styrene (SBS). The French and Germans found that if they added 10%-15% of SBS rubber to asphalt, the asphalt’s characteristics changed to those of the rubber additive. They learned that they could stretch the SBS modified asphalt up to six times its original length and that, unlike the APP, it would return to its original size when allowed to relax. There are a wide range of reinforcements used in SBS roofing materials. These include fiberglass or polyester mats and scrims, or combinations of both. The fiberglass mats range in weight from 1.0 to 2.5 pounds per 100 square feet or around 50 to 125 grams per square meter. Polyester reinforcements range in weight from 3.5 to 5.0 pounds per 100 square feet or 170 to 250 grams per square meter. The type of reinforcement used depends on the material’s performance requirements. SBS membranes can be hot asphalt applied, torch applied, or cold process applied. Polyisobutylene is a synthetic rubber, or elastomer, that was first developed in Germany in the 1930s. It is special because it is the only rubber that is gas impermeable, that is, it is the only rubber which can hold air for long periods of time. It is categorized as an extruded plastomer which is a material that processes like thermoplastics but with rubber properties, requires no vulcanization, is elastic and most importantly, retains flexibility at low temperatures. PIB is typically a sixty mil (.060") membrane. The backside is laminated with a forty mil (.040") rot-proof polyester fleece backing providing a total thickness of one-hundred mils (.100"); this provides a breaking strength that is up to three times that of the sixty mil membrane by itself. PIB is available in either black or white and has excellent resistance to weathering, ultraviolet light, sparks, radiant heat, and gases from industrial plants. It comes with a two inch (2") self-sealing edge that offers excellent seam strength. PIB is installed using either hot asphalt or cold process adhesives. The adherent only partially penetrates the fleece backing leaving the PIB membrane free or "floating" on top of the fleece, therefore chemically and physically unaffected. This also allows the remaining portion of the fleece backing to act as a vapor equalization layer which can eliminate blister development and entrapped moisture. One of the most significant features is the self-sealing edge. It not only provides an excellent waterproof system but it also acts as an expansion joint to relieve stress between the roof membrane and the substrate.
CONS
F. Sprayed Polyurethane Foam (SPF) SPRAYED POLYURETHANE FOAM (SPF): SPF starts out as two liquid components - an isocyanate, known as the "A" component, and a resin (or polyol), the "B" component. When the liquids are mixed at a one-to-one ratio, a chemical reaction occurs and the mixture expands 20 or 30 times forming a solid, monolithic (seamless), closed-cell, fully-adhered roof system that provides excellent water-resistance and thermal insulating abilities. SPF adheres to just about everything so it can be installed over concrete, wood, steel, and most existing roof systems (EXCEPT APP!) which saves on the expense of roof removal and landfill fees. SPF mechanics can spray apply a tapered roof system with the foam which eliminates the need for costly tapered insulation systems. The cants and vertical wall terminations are also spray applied making them an integral part of the roof system and minimizing additional component costs. The "A" and "B" components of SPF are pumped out of separate 55 gallon drums, are mixed at the spray gun, and are applied in what are known as "passes". A pass is a single application of foam and can vary in thickness from 1/2 inch to 1 inch or so. Therefore, SPF roofs that are several inches thick are applied in multiple passes. SPF must have a protective elastomeric coating installed over it because it's very susceptible to UV and mechanical damage. Elastomeric means the coating must be able to stretch with the foam and return to its original shape. Coatings are spray applied and can be acrylic, silicone, butyl rubber, and different urethanes. All have different physical characteristics and varying costs. Coatings are usually installed in three stages: a base coat, a mid-coat, and a final coat. Granules can be embedded into the mid and top coat or only the top coat for added protection against UV and mechanical damage and to increase the system's fire resistance. When most people hear of a "foam" roof, they automatically think of the type of soft foam similar to that used for seat cushions and are concerned that they won't be able to walk on it without causing problems or damaging the roof. Foam roofs are very durable and can handle foot and construction traffic as well as other roofs. They are still susceptible to damage from dropped tools just as any other roof but the damage is more easily seen and can most often be repaired with some simple polyurethane caulking. Density of SPF is important when it comes to strength and Thermal Resistance. Obviously, higher density means increased strength and higher R-value. Most SPF roofs have densities ranging from about 2.5 pounds per cubic foot to 3 pounds per cubic foot. Three pound density foam has a compressive strength of about 50 psi and an R-value of 7.14 installed and 6.86 aged (these numbers may vary slightly depending on the foam manufacturer). Here's an example of how well a good SPF roof insulates. A school district in southern California had recently installed some new, one-room relocatable classroom buildings. During the late spring and early fall, these classrooms were using their air conditioners an average of 50 minutes every hour. The school district installed foam roofs on some of these classrooms in order to see if it would provide an energy savings. The roofs consisted of three pound density foam, 1.5 inches thick with an acrylic coating system. The air conditioner usage was cut down to fifteen minutes every hour. That's a fifty-eight percent savings on energy costs. Does this mean an SPF roof pay for itself? Absolutely! Texas A&M studies indicate that an SPF roof in Texas and other southern climates can pay for itself in approximately four and a half years. If the coating for an SPF roof is properly maintained, then an SPF roof can last a very long time. Every ten or fifteen years, depending on the type and amount of coating installed, the roof will need to be cleaned, primed, and recoated. If this is done, then a quality SPF roof could last 50 years or longer. As with all other roof systems, cost depends on several factors. Some of which include building accessibility, complexity of project, foam thickness, foam coating system, and geographical location. Costs may start at about $2.50 per square foot for a cheap system and go up from there. Foam roofing requires a lot quality control by the foam mechanics who do the work. If the gun gets dirty or a hose gets clogged or any one of a hundred things goes wrong, the mechanics must be able to recognize the problem and be willing to shut down operations until the problems can be taken care of. This isn't an easy thing to do because shutting down an operation costs a lot of time and money and may cost the mechanic a bonus for the job. Pride in workmanship is an extremely important factor in a quality foam roof. TPO: Thermoplastic Olefin or Polyolefin TPO membranes are single-ply roof membranes constructed from ethylene propylene rubber. They are designed to combine the durability of rubber with the proven performance of hot-air weldable seams. They have been tested as having excellent resistance to ozone, are algae-resistant, environmentally friendly and safe to install. The material's manufacturers are so confident in properly welded seams that the material is sometimes advertised as a monolithic (seamless) roof. Seam strengths are reportedly 3 to 4 times those of EPDM's adhesive and tape seams. TPO is highly resistant to tears, impacts, and punctures with good flexibility to allow for building movement. TPO's are available in white, light gray, and black with thicknesses of either 45 mils (.045") or 60 mils (.060"). The width of the membrane depends on the manufacturer but they usually come in widths of six to six-and-a-half feet and are one-hundred feet in length. TPO membranes are installed fully-adhered, mechanically-attached or ballasted. Fully-adhered means that the roof is "glued" to the substrate using a special adhesive. What actually happens is the glue creates a chemical bond with the membrane. Ballasted simply means the membrane is loose laid over the top of the roof, sealed at all penetrations and around the perimeter, and then a ballast is put on it to hold it in place. Ballast usually consists of smooth, round, river rock 2" - 3" in diameter and is applied at a rate of 1,000 to 1,200 pounds per roof square (100 sq. ft.). Sometimes concrete pavers are used in their place. These average 20 pounds per square foot. Mechanically-attached membranes are those that use some type of special screw-type fastener to secure it. The type of fastener will depend on the type of substrate but all fasteners are generally screw-type fasteners. |
||||||
|
||||||
 |
 |
|||||