TOPIC 6
ROOF DESIGN
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TOPIC CONTENT: ROOF DESIGN
6.1 ROOF SYSTEM 6.1.1 Types of Roof 6.1.2 Roof Performance 6.1.3 Roof Design Requirement6.2 ROOF STRUCTURAL DESIGN 6.2.1 Pitched Roof 6.2.2 Flat Roof 6.2.3 Shell Roof 6.2.3 Shell Roof
6.1 ROOF SYSTEM
6.1 ROOF SYSTEM
6.1.1 TYPES OF ROOF
6.1.1 TYPES OF ROOF
PITCHED ROOF
GABLE ROOF
- Description: A gable roof features two sloping sides that meet at a ridge, forming a triangular shape at each end of the building.
- Advantages: Excellent for shedding water and snow; allows for good ventilation; simple and cost-effective.
- Disadvantages: Can be prone to wind damage if not properly designed; may not be ideal in areas with high wind or hurricane risk.
HIP ROOF
- Description: A hip roof has slopes on all four sides, which come together at the top to form a ridge.
- Advantages: Provides better stability and wind resistance compared to gable roofs; offers good drainage and allows for additional living space in the attic.
- Disadvantages: More complex and costly to construct; can have limited attic space.
SHED ROOF
- Description: A shed roof has a single sloping plane, often used for modern or industrial buildings.
- Advantages: Simple to construct; provides a clean, contemporary look; good for collecting rainwater.
- Disadvantages: Limited in terms of architectural variation; may not be suitable for heavy snow loads without proper support
MANSARD ROOF
- Description: A mansard roof has two slopes on each side, with the lower slope being steeper than the upper slope. It creates a nearly vertical wall.
- Advantages: Maximizes living space in the attic or top floor; can be visually appealing and adds historic charm.
- Disadvantages: More complex and expensive to build; can be prone to leaks if not properly constructed.
GAMBREL ROOF
- Description: A gambrel roof is similar to a mansard roof but has two symmetrical sides with a steep lower slope and a shallower upper slope.
- Advantages: Provides more attic space; often used in barn-style or traditional buildings.
- Disadvantages: Can be more prone to damage in high winds; requires proper maintenance to prevent leaks.
BUTTERFLY ROOF
- Description: A butterfly roof features two opposing slopes that angle up towards the center, resembling the wings of a butterfly.
- Advantages: Allows for high ceilings and lots of natural light; good for collecting rainwater.
- Disadvantages: Complex design can be costly; potential for water pooling in the central valley if not properly designed.
SKILLION / LEAN-TO ROOF
- Description: Also known as a mono-pitched or lean-to roof, a skillion roof has a single, sloping plane.
- Advantages: Simple and modern design; effective for rainwater runoff; often used in contemporary architecture.
- Disadvantages: Can limit interior space; may not be suitable for areas with heavy snowfall.
HEXAGON ROOF
- Description: The roof consists of six interconnected panels, each forming one side of the hexagon. This shape can be used in various configurations, from a simple flat hexagonal roof to more complex, multi-faceted designs.
- Advantages: Unique aesthetic, evenly distributed load, multiple facets allowed for improved airflow and efficient rainwater drainage
- Disadvantages: Complex construction requiring precision and high cost.
FLAT ROOF
FLAT SLAB ROOF
- Description: A flat roof is almost level, with a slight pitch for drainage.
- Advantages: Easy and cost-effective to build; provides usable space for rooftops gardens, terraces, or solar panels; simple to access for maintenance.
- Disadvantages: Prone to water pooling and leaks if not properly maintained; requires regular inspection and maintenance.
GREEN ROOF
- Description: A green roof incorporates vegetation and a growing medium on top of a conventional roofing system.
- Advantages: Provides natural insulation; reduces stormwater runoff; improves building aesthetics and energy efficiency.
- Disadvantages: Requires careful planning and maintenance; can be expensive to install.
PARAPET WALL ROOF
- Description: An extended exterior wall giving the building a Flat Roof finish, but may have inclined surface within the boundary for water run-off.
- Advantages: Provides image of Flat roof. And allow safe access for roof for maintenance
- Disadvantages: Requires proper drainage and inclide roof surface to provide proper drainage of rainwater.
SHELL ROOF
characterized by its curved, thin, and often concrete or composite shell structure. It typically involves a shell-like form that can span large distances without the need for interior supports. Shell roof creates striking smooth continuous surface of large span, almost of any shape and size. The absence of internal supports allows for open, flexible interior spaces.
DOME ROOF
- Description: A dome roof is a curved roof that forms a hemispherical shape, often used for structures like observatories or churches.
- Advantages: Provides a unique architectural appearance; good for natural ventilation and light distribution.
- Disadvantages: Complex and expensive to construct; can be challenging to integrate with conventional building designs.
HYPERBOLIC PARABOLOID
- Description: This type of shell roof is formed by intersecting two parabolas. The shape is often used for its efficiency in covering large spans with minimal material. It has a distinctive saddle shape.
- Advantages: Large Span & Aesthetic appeal
- Disadvantages: Complexity and high cost in designing. Thermal properties and acoustic issues.
THIN SHELL CONCRETE ROOF
- Description: characterized by a thin, continuous concrete layer that forms a shell-like surface. These structures use the inherent strength of concrete combined with geometric forms to create lightweight and efficient coverings.
- Advantages: Reduced usage of material & even load distribution. Uninterrupted interior space. Good thermal & insulation control
- Disadvantages: Precision required for formwork. Concrete is prone to cracking
TENSIONED FABRIC SHELL ROOF (Tensile)
- Description: uses the principles of tensile strength to support and shape the roof, by using durable and flexible membrane such as PTFE
- Advantages: Lightweight, able to reach greater span without the need for internal support. Translucent membrane allowed natural light to penetrate
- Disadvantages: Weather sensitivity for certain material, and low acoutic performance
FOLDED PLATE ROOF
- Description: consist of multiple flat panels or plates that are folded at specific angles to create a three-dimensional effect. The folds can form various patterns, such as zigzag, sawtooth, or more complex forms, depending on the design requirements.
- Advantages: Structural efficiency for effective load distribution allowing larger span without the need for intermediate support
- Disadvantages: Complex construction requiring precision and high cost.
GRID SHELL
- Description: combines the principles of a grid (a network of intersecting lines or members) with the form of a shell (a thin, curved surface).
- Advantages: Low material usage, lightweight, even load distribution. Uninterrupted interior space
- Disadvantages: Complex construction requiring precision and high cost.
6.1.2 ROOF PERFORMANCE
6.1.2 ROOF PERFORMANCE
ROOF DRAINAGE
GUTTER is installed along the eaves of a roof to collect rainwater and direct it towards downspoutROOF DRAINS/SCUPPER are installed in flat or low-slope roofs to collect and remove waterRAIN WATER DOWNPIPE channels water from either Gutter or Roof Drains to the ground
K-STYLE GUTTERThese are the most common type of gutter and are often seen on modern homes. They have a flat bottom and a decorative front that resembles a crown molding or "K" shape. They can handle a large volume of water and are often used for their aesthetic appeal.They come in standard 5-inch to 6-inch widths and often feature rectangular downspouts. They also have a flat back and can be nailed directly into your fascia boards, making them easy to install.
HALF-ROUND GUTTERThese gutters are circular in cross-section and are often found on older or historic homes. They are less conspicuous and have a classic appearance. They tend to be more effective at handling debris since the rounded shape prevents clogging.
Half-round gutters come in 5-inch to 6-inch widths.
Half-round gutters come in 5-inch to 6-inch widths.
BOX GUTTERAlso known as "eaves gutters," these are built into the structure of the roof and are often used in commercial or industrial buildings. They are rectangular and hidden from view, providing a streamlined look (industrial aesthetics) and reducing the risk of clogging.
They usually come in 7-inch and 8-inch widths, but some are as wide as 10 inches.
Since the box design is rectangular, it can be adjusted to suit many size and different types of roof like Butterflyr Roof and Parapet Wall Roof.
They usually come in 7-inch and 8-inch widths, but some are as wide as 10 inches.
Since the box design is rectangular, it can be adjusted to suit many size and different types of roof like Butterflyr Roof and Parapet Wall Roof.
Downspout: RAIN WATER DOWN PIPEVertical pipes that carry water from the gutters to the ground.
Downspout: RAIN CHAIN These are an alternative to traditional gutters, featuring a series of metal cups or links that guide water from the roof to the ground. They are decorative and can add an artistic element to the exterior of a building, but they are more commonly used in areas with less rainfall.
LEAF-GUARDScreens that prevent debris from entering the drainage system within the gutter.
ROOF DRAIN
- Drain Basins: Recessed areas that collect water.
- Strainers: Screens that prevent debris from entering the drainage system.
- Pipes: Conduit that channels water from the roof drain to the building’s drainage system.
ROOF SCUPPER
- Scupper Boxes: Collect water and direct it into downspouts or drainage pipes.
- Overflow Drains: Additional drains to handle excess water in case of blockages.
CATCH BASINCatch basins collect water from downspouts or drains and allow debris to settle before water is directed to underground pipes or storm drains.
- Grates: Cover the catch basin and prevent large debris from entering.
- Sumps: Areas where debris and sediment collect.
ROOF VENTILATION
Proper ventilation helps regulate temperature, control moisture, and extend the lifespan of roofing materials.PASSIVE ROOF VENTILATION:
Advantages:
Disadvantages:
Advantages:
- Low maintenance and cost-effective.
- Uses natural airflow, reducing energy consumption.
Disadvantages:
- Effectiveness can be limited in areas with low wind or poor airflow.
- May not be sufficient for large or complex roof spaces.
ACTIVE ROOF VENTILATION:
Advantages:
Disadvantages:
Advantages:
- Provides enhanced ventilation and airflow, especially in larger or poorly ventilated spaces.
- Can be controlled or automated for better efficiency.
Disadvantages:
- Higher initial cost and ongoing energy consumption (for electric models).
- Requires regular maintenance and potential repairs.
Passive: RIDGE VENTSInstalled along the peak or ridge of a pitched roof. They allow warm air to escape from the attic space.
Passive: SOFFIT VENTSInstalled along the peak or ridge of a pitched roof. They allow warm air to escape from the attic space.
Passive: GABLE VENTSPositioned on the gable ends of the roof. They promote cross-ventilation by allowing air to enter and exit through the gable walls.
Passive: DORMER VENTSFound in the sides of dormers, these vents help with ventilation in areas where additional roof space is created
Active: POWERED ROOF VENTSInclude turbine vents or electric fans that actively expel hot air from the attic space. Examples are attic fans and roof-mounted ventilators.
Active: ELECTRIC ATTIC FANInstalled in the roof or attic, these fans are powered by electricity and can be thermostatically controlled to operate when needed.
Active: SOLAR-POWERED VENTSUse solar panels to power fans that help with ventilation. They are energy-efficient and reduce electricity costs.
ROOF INSULATION
Roof insulation is crucial for maintaining energy efficiency, enhancing comfort, and preventing issues like ice dams and condensation in buildings.
FIBERGLASS INSULATION
- Form: Batts, rolls, or loose-fill.
- Characteristics: Made from glass fibers, it is effective at trapping heat and preventing heat loss. It's also resistant to moisture, although it must be properly installed to avoid compression and maintain its R-value.
- Applications: Commonly used in attics and between rafters.
FOAM BOARD INSULATION
- Form: Rigid panels.
- Characteristics: Made from materials like expanded polystyrene (EPS), extruded polystyrene (XPS), or polyisocyanurate (polyiso). These boards are highly effective in insulating and are moisture-resistant.
- Applications: Used in both flat and pitched roofs, particularly effective for insulating over decking or as part of a layered system.
SPRAY FOAM INSULATION
- Form: Spray-applied.
- Characteristics: Expands on application to fill gaps and voids, providing a high R-value per inch and acting as both an insulator and an air barrier. It can be open-cell (less dense, good for interior applications) or closed-cell (denser, better for moisture resistance).
- Applications: Ideal for irregularly shaped spaces and areas with complex geometries.
REFLECTIVE / RADIANT BARRIER INSULATION
- Form: Foil sheets or reflective paints.
- Characteristics: Designed to reflect radiant heat away from the roof, reducing cooling costs in hot climates. They are usually installed in attics or on roof decking.
- Applications: Most effective in warm climates where cooling costs are a concern.
CELLULOSE INSULATION
- Form: Loose-fill.
- Characteristics: Made from recycled paper products and treated with fire retardants. It has good thermal performance and is often used in attics and wall cavities.
- Applications: Suitable for both new and existing homes, especially for adding insulation to existing spaces.
MINERAL WOOL (ROCK WOOL) INSULATION
- Form: Batts or loose-fill.
- Characteristics: Made from molten rock or slag, it is fire-resistant and provides excellent soundproofing qualities. It also has good thermal resistance and moisture resistance.
- Applications: Often used in commercial buildings and high-temperature areas.
ROOF WATERPROOFING
Roof waterproofing is essential for protecting a building from water damage, extending the lifespan of the roof, and maintaining energy efficiency
BITUMINOUS MEMBRANES
- Types: Modified Bitumen (MB), Built-Up Roofing (BUR).
- Characteristics:
- Modified Bitumen: Consists of bitumen with added modifiers like APP (Atactic Polypropylene) or SBS (Styrene-Butadiene-Styrene) to enhance flexibility and durability.
- Built-Up Roofing: Layers of bitumen and reinforcing fabrics (such as fiberglass or polyester) are applied in multiple layers.
- Applications: Commonly used on flat or low-slope roofs, offering good durability and weather resistance.
EPDM (Ethylene Propylene Diene Monomer)
- Characteristics: A type of synthetic rubber that is highly durable, flexible, and resistant to UV rays and extreme temperatures.
- Applications: Ideal for flat or low-slope roofs, and it’s available in rolls or as a liquid application.
TPO(Thermoplastic Olefin)
- Characteristics: A single-ply membrane made from a blend of polypropylene and ethylene-propylene rubber. It is reflective, energy-efficient, and heat-welded at the seams for a watertight seal.
- Applications: Suitable for flat or low-slope roofs and known for its energy efficiency and resistance to UV light.
PVC(Polyvinyl Chloride)
- Characteristics: A single-ply membrane that is durable, flexible, and resistant to chemicals and moisture. It also has good fire resistance.
- Applications: Commonly used in commercial buildings, especially in areas exposed to chemicals or high foot traffic.
LIQUID-APPLIED MEMBRANES
- Types: Acrylic, Polyurethane, Silicone.
- Characteristics: These are applied as a liquid that cures to form a seamless, watertight membrane. They can be applied over existing roofs and are excellent for complex roof shapes.
- Applications: Suitable for various roof types, including flat and sloped roofs. Each type has its own benefits, such as UV resistance (acrylic), flexibility (polyurethane), or durability (silicone).
ROOF SAFETY & ACCESSIBILITY
Ensuring roof safety and accessibility is essential for the protection of individuals working on or accessing the roof and for maintaining the roof itself.FALL PROTECTION
EDGE PROTECTION
- Guardrails: Install guardrails around the roof perimeter to prevent falls. These should be sturdy and comply with safety standards.
- Safety Nets: Use safety nets to catch any falling objects or individuals, particularly in high-risk areas.
- Fall Arrest Systems: Implement fall arrest systems such as harnesses, lanyards, and anchor points for workers to use when working at heights.
EDGE PROTECTION
- Parapet Walls: Construct parapet walls around the roof edge to provide a physical barrier and prevent falls.
- Roof Edge Barriers: Install roof edge barriers or railings where parapet walls are not feasible.
ACCESS SAFETY
- Access Points: Design safe access points such as ladders, stairs, or ramps that comply with building codes and safety standards.
- Secure Ladders: Ensure that ladders are securely positioned and stable. Use ladder stabilizers to prevent slipping.
- Roof Access Hatches: Install roof access hatches or doors that are properly secured and easily accessible.
6.1.3 ROOF DESIGN REQUIREMENT
6.1.3 ROOF DESIGN REQUIREMENT
1. Structural Integrity
2. Climate and Weather Considerations
3. Waterproofing and Drainage
4. Ventilation
5. Aesthetic and Design Considerations
6. Energy Efficiency
7. Safety and Accessibility
8. Local Building Codes and Regulations
9. Material Selection
10. Sustainability and Environmental Impact
11. Maintenance and Longevity
- Load-Bearing Capacity: The roof must support its own weight (dead load), along with any additional loads such as snow, wind, and live loads (e.g., maintenance personnel or equipment).
- Support Systems: Proper support systems, such as rafters, trusses, or beams, are necessary to distribute loads evenly and maintain structural stability.
2. Climate and Weather Considerations
- Weather Resistance: The roof should be designed to withstand local weather conditions, including rain, snow, wind, and sun exposure. Different roofing materials and designs offer varying degrees of weather resistance.
- Insulation: Adequate insulation is essential to maintain indoor comfort, reduce energy costs, and prevent issues like condensation and ice dams. The type of insulation will depend on the climate and roof type.
3. Waterproofing and Drainage
- Waterproofing: The roof must be waterproof to prevent leaks and water damage. This involves selecting appropriate materials and ensuring proper installation techniques.
- Drainage: Proper drainage systems, including gutters, downspouts, and drainage layers, are crucial to direct water away from the roof and building to prevent ponding and leaks.
4. Ventilation
- Roof Ventilation: Adequate ventilation helps regulate temperature and humidity in the attic or roof space, reducing the risk of moisture buildup, mold, and structural damage. It also helps with energy efficiency.
- Types of Ventilation: This includes passive vents (e.g., ridge vents, soffit vents) and active vents (e.g., powered ventilators).
5. Aesthetic and Design Considerations
- Architectural Style: The roof design should complement the architectural style of the building. This includes considering roof shape, pitch, and material.
- Visual Appeal: The choice of roofing material, color, and design elements should enhance the building's appearance and align with the surrounding environment.
6. Energy Efficiency
- Reflectivity: Roof materials with high reflectivity can reduce heat absorption, leading to lower cooling costs and improved energy efficiency.
- Insulation: Proper insulation and ventilation can help maintain a consistent indoor temperature and reduce energy consumption.
7. Safety and Accessibility
- Safety: Ensure the roof design includes safety features such as guardrails, fall protection systems, and safe access points for maintenance.
- Accessibility: Design access points and pathways for easy and safe maintenance and repairs. Consider incorporating features like walkways or access hatches.
8. Local Building Codes and Regulations
- Compliance: Ensure the roof design complies with local building codes and regulations, which may specify requirements for load-bearing capacity, materials, and construction methods.
- Permits: Obtain necessary permits and approvals before construction begins.
9. Material Selection
- Durability: Choose materials that are durable and suitable for the local climate. Consider factors like lifespan, maintenance needs, and resistance to weather conditions.
- Cost: Balance material costs with durability and aesthetic preferences. Different materials offer varying levels of performance and cost.
10. Sustainability and Environmental Impact
- Eco-Friendly Materials: Consider using sustainable or recycled materials to reduce the environmental impact.
- Green Roofs: Explore options like green roofs or living roofs for added environmental benefits, such as improved insulation and stormwater management.
11. Maintenance and Longevity
- Ease of Maintenance: Choose a roof design that allows for easy maintenance and repair. Regular inspections and upkeep can extend the roof's lifespan.
- Longevity: Consider the expected lifespan of the roofing materials and design for long-term performance and durability.
6.2 ROOF STRUCTURAL DESIGN
6.2 ROOF STRUCTURAL DESIGN
6.2.1 PITCHED ROOF
6.2.1 PITCHED ROOF
HEXAGON ROOF
characterized by its six-sided geometric shape
6.2.2 FLAT ROOF
6.2.2 FLAT ROOF
FLAT SLAB ROOF
REINFORCED CONCRETE SLABDescription:
- Structure: A common type of slab made from concrete reinforced with steel bars or mesh to improve its strength and load-bearing capacity.
- Solid Slab: A continuous concrete slab with no voids or openings, providing a strong and stable surface.
- Flat Slab: A solid slab without beams, supported directly by columns, often used in modern high-rise buildings.
- Durability: Highly durable and capable of supporting heavy loads.
- Fire Resistance: Provides good fire resistance due to the concrete’s properties.
- Weight: Can be quite heavy, requiring additional structural support.
- Cost: Generally more expensive due to the amount of concrete and reinforcement required.
- Commonly used in commercial, residential, and industrial buildings for its strength and reliability.
PRECAST CONCRETE SLABDescription:
- Structure: Slabs are cast in a controlled factory environment before being transported to the construction site and installed.
- Hollow Core Slab: Contains hollow cores (voids) running through the slab, reducing weight while maintaining strength.
- Solid Slab: A precast slab without voids, providing a solid surface.
- Quality Control: Manufactured under controlled conditions for consistent quality.
- Speed of Construction: Faster to install than cast-in-place slabs, as they are pre-made.
- Transportation: Requires transportation and handling equipment, which can add to the cost.
- Customization: Limited in terms of customization compared to cast-in-place options.
- Used in commercial and residential buildings where speed and quality are critical.
POST-TENSIONED CONCRETE SLABDescription:
- Structure: Concrete slab with steel cables or tendons that are tensioned after the concrete has cured, enhancing its strength and load-bearing capacity.
- Reduced Slab Thickness: Allows for thinner slabs with longer spans, reducing the overall weight of the structure.
- Crack Control: Helps to control cracking and improve durability.
- Complexity: Requires specialized equipment and expertise for installation and tensioning.
- Cost: Generally more expensive than traditional reinforced concrete slabs.
- Ideal for high-rise buildings, long-span structures, and situations where reduced slab thickness is desired.
COMPOSITE SLABDescription:
- Structure: Combines concrete with another material, such as steel decking, to create a composite system that utilizes the strengths of both materials.
- Metal Decking Slab: Uses metal decking as a formwork that supports the concrete until it cures and provides additional strength once the concrete is set.
- Speed of Construction: Faster to install due to the use of prefabricated metal decking.
- Load-Bearing Capacity: Offers high load-bearing capacity and efficient use of materials.
- Cost: Can be more expensive due to the additional materials and coordination required.
- Complexity: Requires careful design and installation to ensure the composite action between materials.
- Common in commercial and industrial buildings where speed and efficiency are important.
GLASS ROOF SLABDescription:
- Structure: Incorporates glass panels as part of the roof slab, often used in conjunction with other structural elements.
- Natural Light: Allows for the entry of natural light into the building, creating bright and open spaces.
- Aesthetic Appeal: Provides a modern and visually appealing roof design.
- Insulation: Can be less effective at insulating compared to other materials, requiring additional measures to control temperature.
- Maintenance: Glass requires regular cleaning and maintenance to keep it clear and functional.
- Often used in atriums, skylights, and modern buildings where natural light and aesthetic design are priorities.
FLAT TRUSS ROOF
TIMBER ROOF SLABDescription:
- Structure: Uses timber or engineered wood products to create a roof slab, often in the form of wooden planks or panels.
- Timber Decking: Uses wooden planks or boards laid over beams to form the roof surface.
- Cross-Laminated Timber (CLT): Engineered wood panels made by gluing layers of timber together, offering high strength and stability.
- Aesthetic Appeal: Provides a natural, warm aesthetic that is often desired in residential and some commercial applications.
- Sustainability: Timber is a renewable resource and can be more sustainable than concrete or steel.
- Fire Resistance: Timber is less fire-resistant than concrete or steel, although treatments and design can improve this.
- Maintenance: Requires regular maintenance to prevent issues such as rot or insect damage.
- Suitable for residential buildings, eco-friendly designs, and some commercial structures.
GREEN ROOF
Green roofs, also known as living roofs, are designed to support vegetation and provide various environmental benefits
EXTENSIVE GREEN ROOFCharacteristics:
- Layer Structure: Typically consists of a thin layer of growing medium (often 2-6 inches deep), lightweight vegetation, and a drainage layer.
- Vegetation: Usually features low-maintenance, drought-resistant plants like succulents, mosses, and grasses.
- Low Maintenance: Requires minimal upkeep.
- Cost-Effective: lighter weight of the system and less complex infrastructure.
- Weight Load: Suitable for retrofitting on existing buildings
- Limited Plant Selection: The shallow growing medium limits the types of plants
- Less Insulation: Offers less thermal insulation compared to intensive green roofs.
- Ideal for residential buildings, garages, and commercial buildings where minimal maintenance is desired.
SEMI-INTENSIVE GREEN ROOFCharacteristics:
- Layer Structure: Intermediate depth of growing medium, usually between 4-12 inches. This type combines features of both extensive and intensive green roofs.
- Vegetation: Supports a moderate range of plants, including perennials and small shrubs.
- Balanced Maintenance: Offers a compromise between the low maintenance of extensive green roofs and the biodiversity of intensive green roofs.
- Versatility: Can be adapted to various building types and applications.
- Moderate Cost: Costs are higher than extensive green roofs but lower than intensive green roofs.
- Moderate Weight: Requires structural considerations to support the weight of the medium and vegetation.
- Suitable for both residential and commercial buildings where a moderate level of plant diversity and maintenance is acceptable.
INTENSIVE GREEN ROOFCharacteristics:
- Layer Structure: Features a deeper growing medium (typically more than 6 inches), which can support a wide variety of plants, including shrubs and small trees.
- Vegetation: Allows for a more diverse plant selection, including grasses, flowers, herbs, and even small trees.
- High Biodiversity: Supports a broad range of plant species and can create a more garden-like environment.
- Greater Insulation: Provides better thermal insulation and can help with stormwater management due to the deeper substrate.
- Higher Maintenance: Requires more maintenance due to the complexity of the plant life and irrigation needs.
- Cost: More expensive to install and maintain due to the heavier infrastructure and increased weight load.
- Suitable for new constructions or major renovations where the building structure can support the additional weight. Common in commercial buildings, public spaces, and residential areas where a green space is desired.
MODULAR GREEN ROOFCharacteristics:
- Structure: Pre-planted modules or trays that are installed on a roof. These can be swapped out or replaced if needed.
- Vegetation: Typically contains pre-grown plants, which can include grasses, succulents, and small perennials.
- Ease of Installation: Modular systems are generally easier and quicker to install compared to traditional green roofs.
- Flexibility: Allows for easy replacement and maintenance of individual modules.
- Limited Customization: Less flexibility in plant selection and design compared to custom-built green roofs.
- Cost: Modular systems can be more expensive than traditional extensive green roofs.
- Suitable for both new constructions and retrofits where a modular approach is preferred for ease of installation and maintenance.
ROOF PLANTER BOXCharacteristics:
Applications:
- Structure: designed to hold plants on a rooftop. Can be made from concrete, steel or timber
- Vegetation: Depending on the size and depth of soil contained within the planter box.
- Space Efficiency: Flexibility in future changes
- Thermal insulation: Helps insulate building from roof top level downwards from harsh sun.
- Stormwater drainage: Can be used to absorbed stormwater runoff and ease the burden on drainage system
- Plant growth: Limited as with any other potted plants
Applications:
- Suitable for both new constructions and retrofits where a modular approach is preferred for ease of installation and maintenance.
LIVING WALL (GREEN WALL)Characteristics:
- Structure: Vertical green systems that use a variety of planting methods, such as modular panels, trellis systems, or hydroponic systems.
- Vegetation: Can include a wide variety of plants, from small herbs to climbing vines.
- Space Efficiency: Ideal for urban environments where ground space is limited.
- Aesthetic Appeal: Provides a visually appealing green feature in urban settings.
- High Maintenance: Requires ongoing maintenance and irrigation.
- Cost: Generally higher installation and maintenance costs compared to green roofs.
- Often used in urban environments, commercial buildings, and as decorative features on walls.
GREEN ROOF DETAILS
GREEN ROOF LIGHTING
GREEN ROOF DRAINAGE
6.2.3 SHELL ROOF (Parametric)
6.2.3 SHELL ROOF (Parametric)
LATTICE DOME
A lattice dome consists of discrete and normally elongated elements shaping a grid pattern. Lattice domes may include a single layer or multiple layers, may have pinned or rigid joints, and may work only in tension and compression or in tension, compression, and bending. Lattice domes are named according to their grid patterns and the geometry of their curvature.
RIBBED DOMEA ribbed dome consists of several ribs and rings that intersect each other at rigid joints. A rib is entitled to a group of elements that lie along a meridional line, and a ring is entitled to a group of elements that constitute a horizontal polygon.
Astrodome, Houston, Texas, 1964
LAMELLA DOMEA lamella dome consists of intersecting diagonal elements and may or may not include one or more rings.
Tacoma Dome, Washington, US, 1983
DIAMATIC DOMEDiamatic domes consist of several sectors whose side boundaries are along two meridians of the circumsphere of the dome, and the bottom boundary is along a parallel of the circumsphere. An important characteristic of diamatic domes is that they do not present any problem regarding ‘element cluttering’ near the crown.
Climatron, Missouri Botanical Garden, St. Louis, Missouri, USA, 1960
GEODESIC DOMEA geodesic dome is created by mapping a triangulated pattern onto a number of faces of a polyhedron and projecting the results onto a sphere that is concentric with the initial polyhedron. An icosahedron (20-faced regular polyhedron) is one of the common volumes used in creating geodesic domes.
Joe and Rika Mansueto Library, The University of Chicago, USA
ELLIPTICAL DOMEShaped like an ellipse, this dome has a more elongated form compared to spherical domes. It can create unique architectural effects and is often used in modern and contemporary buildings.
MONOLITHIC DOME
A monolithic dome is a type of dome construction characterized by its single, continuous, and unified shell. This design creates a seamless and structurally efficient form with several distinctive features and advantages.Shape: Monolithic domes have a smooth, curved surface that forms a single, uninterrupted shell. This can be a full dome or a partial dome, depending on the design.Materials: Commonly constructed from reinforced concrete, but other materials such as shotcrete (sprayed concrete), steel, and composites can also be used. The structure often includes a layer of insulation and a weatherproofing layer.Construction: The dome is typically constructed using a form or mold that shapes the material as it is applied. For concrete domes, a common method involves inflating a balloon or using a geodesic frame as a temporary form. Once the material cures, the form is removed.
ROTUNDA ROOF
- Description: circular or semi-circular, forming a dome or vaulted ceiling. It often includes a central opening or oculus at the top, which can be used for natural light or ventilation.
- Advantages: Provides a unique architectural appearance; good for natural ventilation and light distribution.
- Disadvantages: Complex and expensive to construct; can be challenging to integrate with conventional building designs.
FOLDED PLATE ROOF
HYPERBOLIC PARABOLOID ROOF (Hypar)
a type of shell roof with a distinct geometric shape that resembles a saddle or a Pringle’s potato chip, formed by the intersection of two hyperbolic curves. This surface is generated by moving a parabola in a hyperbolic path.
- The shell structure is doubly ruled, with the vertical ribs/ rules being parabolic, and the horizontal ribs form the hyperbolic curvature.
- This unique shell structure can be as thin as 50 mm and is structurally stable to cover spans as large as 35m.
- The forces and loads acting on the shell induce compression in the inner-built portion of the arches while also causing tension in the internal cables or reinforcements.
- Hyperbolic-paraboloids are lightweight shell structures that derive their stability from the form and not the mass, unlike standard structural members.
- The curvilinear surfaces often act as the walls as well as the roof.
- Since the form is made up of curved surfaces, it has a reduced risk of buckling failure due to compression, which is commonly observed in-plane structural members.
- The versatility of the form and the strength due to the rules along the two axes enables it to withstand the dead loads and the wind load.
- Hypars can be constructed with many construction materials based on usage, such as – Reinforced concrete, Steel members, Aluminum, Timber, Plywood, Bamboo, etc.
TENSIONED FABRIC ROOF (Tensile)
The term Tensile described a category of building in which the load bearing capacity is achieved through tension stress, where the exterior shell is a fabric material spread over a framework. The fabric maintained in tension in all directions to provide stability.HYPERBOLIC PARABOLOIDThese structures rely on two opposing curvatures, also known as anticlastic, for their stability. A specific type of double-curved tensile roof, the hyperbolic paraboloid is defined by its saddle-like shape, created by intersecting two parabolas. This form allows for efficient load distribution and a striking visual effect.
CONICAL TENSIONmembranes are tensioned between a ring at the pinnacle and the lower perimeter support columns. The cones are highly effective for covering large areas and loading heavy rain or snow. The masts can go to the ground or can utilize a ‘flying’ mast where cables are used in tension supporting the mast in the air to allow for an unobstructed space below.
PARALLEL ARCH/BARREL VAULT These symmetrical curved parallel arch designs form an incredibly functional tensioned membrane canopy that can span long distances such as a sports arena or smaller areas such as an entryway. Depending on the spans, a barrel vault system can be a very cost-effective way to incorporate tensile membrane on a project due to the repetitive nature of the design and efficiencies of materials.
PNEUMATIC These structures rely on air pressure to create lightweight, flexible, and energy-efficient buildings. The roof relies on a continuous supply of power to maintain air pressure. If the power fails or if there is a malfunction in the air supply system, the roof's integrity can be compromised.
AIR-SUPPORTED PNEUMATIC STRUCTURES
- It consist of a single layer of fabric supported by a continuous flow of air. This creates a dome-like structure that is lightweight, yet strong enough to support large crowds of people.
- They can also be used as temporary structures for events, which can be inflated and deflated as needed
TENSILE MEMBRANE PNEUMATIC STRUCTURES
- made up of a series of cables that support a flexible fabric membrane. This creates a lightweight, yet durable structure that can be easily shaped into a variety of forms .
- BASE PLATE - Connection to concrete foundation pillar
2. MEMBRANE - Forms the enclosure of the structure
3. MEMBRANE PLATE - Provide connection between the membrane and the structural elements, accepts cetenary cables and pin connection hardware
3. BALE RING - Provide connection between the membrane and the structural elements, used at the top of a conical shape
3. CABLE CLAMP
THIN SHELL CONCRETE ROOF
- characterized by a thin, continuous concrete layer that forms a shell-like surface., often made from reinforced concrete or precast modular panels
- These structures use the inherent strength of concrete combined with geometric forms to create lightweight and efficient coverings.
- The primary material used is concrete, often reinforced with steel rebar or mesh. The concrete layer is thin, generally ranging from 5 to 30 centimeters (2 to 12 inches) thick.
- Constructing thin concrete shells requires precise formwork and accurate shaping to achieve the desired geometry. This complexity can increase construction time and costs.
- Thin concrete shells can be prone to cracking, especially if not properly reinforced or if subjected to excessive stresses.
Formwork for Shell Concrete Roof
GRID SHELL ROOF
- combines the principles of a grid (a network of intersecting lines or members) with the form of a shell (a thin, curved surface). The grid shell structure is characterized by its use of a flexible grid framework that supports a shell-like surface, allowing for the creation of lightweight, efficient, and aesthetically pleasing buildings or covers.
- For larger span or greater height with more load requirement, space frame or larger truss can be utilized as the grid network.
- The grid is often designed to be flexible and can be adapted to various shapes and forms. The grid members are typically arranged in a regular pattern but can vary in density and orientation based on design requirements.
- efficient use of materials by providing structural support with minimal weight.
- The grid shell’s curved surface helps distribute loads evenly, reducing stress concentrations and improving overall stability.
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