ROOF CLADDING'S

Single skin profiled metal sheet. Wall and Roof Cladding

Single Skin Roof Sheeting and Wall Sheeting is obviously the most economic way of covering steel framed storage warehouses.

Double skin insulated sheet. Wall and Roof Cladding

Double skin insulated roof sheeting or wall sheeting or both will reduce condensation and reduce temperature change in a storage warehouse. Insulation is essential if the storage space is to be heated or cooled. A double skin roof will reduce the chances of leaks. The fibreglass insulation compacts well for sea freight. If insulation of storage warehouses is required then the double skin system is possibly the most cost effective solution. U value can vary from 0.45 W/°C/m² to 0.20 W/°C/m².

Composite Sandwich. Roof and Microrib Wall Cladding

Composite Double Skin Sandwich Boards can be used for roofing steel framed storage warehouses. A nearly flat mini rib composite sandwich panel can be used on walls. It can be self finish inside and out and can have windows and doors fitted for a smart look. It is often used around main entrances and offices where the rest of the storage shed is clad with type 2.

Roof cladding is a protective layer, like skin, that shields a building's interior and structure from exterior weather and climate. Although the exterior cladding, such as siding, protects a building's walls, roof cladding must be able to effectively deter moisture, winds, temperature and sun from harming a structure. Most often, a roof is clad with shingles or rolled roofing, however other systems protect a roof structure, such as metal panels and rubber roofing.

1. Moisture

   • A structure's interior must be protected from rain and snow. Roof cladding is waterproof and denies moisture from absorbing into the structural sheathing. Asphalt shingles and rolled roofing accomplish this by overlapping, like a fish's scales. Rubber roofing and standing seam metal roofs do this by creating a continuous waterproof sheet across the whole of the roof plane.

   Winds

   • Roof cladding must protect from and resist damage by winds. Areas prone to hurricanes and tornadoes have building codes that require roofs be well fastened to the building's structure. Flat roofed buildings with rubber roofing use a ballast of aggregate to protect the roof from uplift from heavy winds.

   Temperature

   • The roof cladding must be able to insulate a building's interior from the exterior temperature. Most often, this is accomplished with rigid foam insulation. However, other methods, including building up multiple plies of roofing and shingles with high thermal mass, such as terra cotta or slate, can insulate a structure from the roof.

   Sun

   • The roof is very exposed to the sun and the ultraviolet waves that emanate from it. Roof cladding must be resistant to sun damage. So, roofing is often not composed of plastics or wood. Instead, durable materials are used to produce roof cladding. Asphalt, slate and steel are excellent against the sun's rays. The ballast on rubber roofs acts as a sun block, protecting the roof from the degrading solar radiation.

   Future Roof Cladding

   • Although many man-made materials are not appropriate for use as roof cladding, advances are being made with vinyl and other materials to allow them to be used as roofing. In fact, some roofing composed of man-made materials, such as fiberglass, are already being sold. As technology improves materials and methods of creating roof cladding, we may see other new materials, like ceramic, or we may find roofing is applied in broader sheets, covering more surface area with less labor.

Research Topic

The 4Ds of weathertightness

The 4Ds as used in E2/AS1 are:

• Deflection – keeping water away from potential entry points.
• Drainage – providing means of removing water that does enter.
• Drying – allowing any remaining moisture to be removed by ventilation or diffusion.
• Durability – providing materials with appropriate durability

• Deflection: The art of protecting joints
  Keeping water away from entry points will greatly reduce the chance of a joint developing a leak.   The first means of deflection is roof designs, verandahs and overhangs which protect wall surfaces. Other forms of deflection are found in facings, flashings and overhangs which also contribute to reducing water entry.
• 
  Drainage: Allowing unwelcome water to escape
  It is important to allow for water which has entered to drain away. Direct fixed claddings will provide limited drainage if water does get behind and can hold water against underlay, thus it is very unlikely water will be able to drain away. In constructing a drainage cavity behind the cladding, allows the passage of water on the back of the cladding to drain away.
• 
  Drying: Evaporate the rest
  For water that has entered, but has not drained away it must be allowed to dry through diffusion and ventilation ie Brick Veneer, EIFS systems with cavity ventilation holes in bottom tray.
• 
  Durability:  Make it last
  To prevent leaks and to make the building envelope last it is crucial that durable products are used. Leaks have contributed to untreated timber rotting in under two years from lack of water being able to drain away which in turn leads to the establishment of fungi growth which caused not only health issues but spread the rot beyond the original area . The use of timber treatment will markedly slow the establishment of rot and isolate the damage.
  Not only should timber be durable, but also fixings, finishes along with all materials.
• 
  The combination of these 4D’s will ensure that future buildings will be more robust than those which are now experiencing weathertight issues.



RESEARCH TOPIC

INSULATION

Types of Insulation

There are four basic types of insulation: loose fill, batts and blankets, rigid board and spray foam. The most appropriate type of insulation to use will vary based on the type of construction, the extent of the rehabilitation planned and applicable code requirements.

Loose-fill Insulation

Loose-fill insulation includes loose fibers or fiber pellets that are blown into building cavities or attics using special equipment. It generally costs more than batt insulation. However, it usually fills nooks and crannies easier, reduces air leakage better, and provides better sound insulation than natt-type insulation.

Cellulose fiber,

 made from recycled newspapers, is chemically treated for fire and moisture resistance. (Check that the bags are clearly labeled to indicate that the material meets federal specifications for fire resistance). It can be installed in walls, floors or attics using a dry-pack process or a moist-spray technique.

Fiberglass and rock wool loose-fill insulation provide full coverage with a "Blow-in Blanket" System (BIBS) that involves blowing insulation into open stud cavities behind a net.

Loose-fill insulation typically has a value of approximately R-3 to R-4 per inch. Cellulose fiber has approximately 30% more insulating value than loose-fill rock wool for the same number of inches installed.

Batt and Blanket Insulation

Batt and blanket insulation is made of mineral fiber -- either processed fiberglass or rock wool -- and is used to insulate below floors, above ceilings, and within walls. Generally, batt insulation is the least expensive wall insulation material but requires careful installation for effective performance.

This type of insulation is best suited to a standard joist, rafter, or stud spacing of 16 or 24 inches. Batts and blankets come in widths to fit securely between the wood-framing members. Some come with a radiant barrier backing. Batts generally come in lengths of 4 or 8 feet. Blankets come in long rolls that are cut to the desired length for installation. Both batts and blankets typically have an R-value of approximately R-3 per inch of thickness.

Rigid Board Insulation

Rigid board insulation is commonly made from fiberglass, polystyrene, or polyurethane and comes in a variety of thicknesses with a high insulating value (approximately R-4 to R-8 per inch). This type of insulation is used for reproofing work on flat roofs, on basement walls and as perimeter insulation at concrete slab edges, and in cathedral ceilings.

For interior applications it must be covered with 1/2-inch gypsum board or other building-code approved material for fire safety. For exterior applications it must be covered with weather-proof facing. Check the applicable codes to determine local requirements for covering rigid board insulation to achieve fire resistance.

Spray Foam Insulation

Spray foam insulation is a two-part liquid containing a polymer (such as polyurethane or modified urethane) and a foaming agent. The liquid is sprayed through a nozzle into wall, ceiling, and floor cavities. As it is applied it expands into a solid cellular plastic with millions of tiny air-filled cells that fill every nook and cranny. Spray foam insulation should be applied by a professional using special equipment to meter, mix, and spray into place. Spray foam insulation is commonly used for retrofits; it is good for irregularly shaped areas and around obstructions

Spray foam materials cost more than traditional batt insulation. However, since spray foam forms both an insulation and an air barrier, it can be cost competitive with batt insulation because it eliminates the steps for air-tightness detailing (such as caulking, applying housewrap and vapor barrier, and taping joints).

RESEARCH TOPIC

FRAMING
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