Knowledge map – week 7 Detailing for heat and moisture •
how to prevent the water go under the sheeting? b. Eaves: protect wall surface, Flashing is required
c. Wall: put double skin wall to prevent moisture
a. Drain: water carry away to a stone water pipe
b. Box gutters carry water to outside of the buildings. * if its block,
Tanking is effectively basement waterproof main structure, to keep the house in dry. It made with rubber, built around the construction.
Buildings sometimes wrapped with blue sheets SARKING to prevent the water entrance, also prevent the air leakage • Solution: use AMAP i. remove openings ii. keep water away from openings iii. neutralize the forces that move water through openings •
openings can be • 1. predicted/ PLANNED elements e.g windows, doors skylights etc OR 2. unpredictable/ unplanned:poor construction workmanship; deterioration of materials; roof broke at some points.
i. Solutions to prevent water entrance: rely on correct installation, deteriorate overtime due to weathering. 1. sealants 密封剂 e.g silicone. Need to be updated 2. gaskets 垫圈 e.g rubbers ii. solutions to keep water away from the 1st place:s 1. grading slopping roof: water collected in gutters=> discharge water to downpipes and storm water system. Box gutter
2. overlapping cladding and roofing elements.e.g weatherboard and roof tiles, the gap will be filled with concrete water. water water
3. sloping window and door sills; flashings ii. iii. neutralizing the forces • gravity ◦ flashing. Sometimes at top of the window head, internal ◦ slopes and overlaps out
surface tension and capillary action ◦ drip or a break, e.g window sill or parapet drip break water
these gaps and breaks prevent water reaching and entering openings, because the surface tension of the water is broken at the drip and gap location. • Momentum ◦ windblown rain, that can move through simple gaps ◦ to use complex shape slows the momentum of the moisture and helps to deflect the water away. water
air pressure differential from inside and outside
◦ if the pressure is low inside the buildings and higher outside, then there is chance that rainwater will pump into the buildings. ◦ Strategies: AIR BARRIER: applied on the internal side of the labyrinth, (PEC)to balance the pressure in the gap, then the water is no longer pumped to the inside, instead, it will go out from the slope where is has pumped in. ◦ commonly used in high rise buildings.
Controlling heat heat GAIN & LOSS occurs when •
heat is conducted through the building envelope strategies: ▪ Thermal insulation: reduce heat conduction ▪ thermal breaks: made from low conductive materials: rubbers &plastic to reduce the heat transfer from outside to inside when using metal ▪ double glazing/ triple glazing: air spaces between glass panel reduces the flow of heat through the glazed elements. RADIANT heat sources strategies: ◦ reflective surfaces: low-e glass reflective materials to reduce building element from getting too warm, lighter color wall ◦ shading systems: verandahs, eaves, solar shelves, vegetation. Better than curtains THEMAL MASS: large area of mass can be used to absorb and store heat, overtime the temperature will raises. Strategies: to release the temperature and let the heat out. Good at large temperature difference between day and night. ◦ use masonry ◦ concrete ◦ water bodies
RUBBER natural rubber & synthetic rubber • sourced from the rubber tree (tree's sap), • synthesized in a laboratory generating a range of variations (plastic)
-distinctive properties: • harder rubbers resist abrasion 损伤, softer provide better seals • low fragility, generally not shatter or break • high ductility, • high flexibility, plasticity and elasticity • waterproof- seals of windows • approximately 1.5 density of water • poor conductors of heat and electricity useful insulation • very durable • recycle • embodied energy • cost effective -use • seals: SILICONE • gaskets and control joints: EPDM • flooring, laboratories: NEOPRNE • insulations around electrical wiring • hosing consideration • exposed to sunlights strategies: • minimize the sun exposure
plastic • from GREEK world 'Plastikos' => able to be moulded into different shapes • made from: carbon, silicon, hydrogen, nitrogen, oxygen and chloride • monomers combine with each other to form polymers -types & uses • Thermoplastic◦ heated and become solid again when cooled, recyclable ◦ PVC (piping, inexpensive, damage to the environment), POLYETHELYNE (insulation material around the hot water pipe), POLYCARBONATE (roofing and walling, provide insulation not easy break), PERSPEX • Thermosetting plastic ◦ can only be shaped once ◦ Melamide formaldehyde- widely used for finishing surfaces ◦ polystyrene- insulation • Elastoners, similar to rubber ◦ EPDM, rubber ◦ Neoprene◦ silicone- waterproof, help to separate metals -properties • medium-low hardness • low medium fragility, generally not shatter or break, sunlight and high temperature can degradation some plastic quite quickly • high ductility • high flexibility
• • • • • • •
waterproof low density, light-weigh poor conductors of heat and electricity durable, cost effective high reusability for thermoplastics and elastomers but limited for thermosetting plastic
consideration • •
weather- degrade when exposed to sunlight => need to maintain avoid sun exposure if possible
Paint • • •
liquid until they are applied on a surface forming=> solid when contact with air purpose: protect and color a particular elements. Clear paints: LACQUERS or VARNISHES
-components • BINDER: the film-forming e.g polyurethanes, polyesters, resins, epoxy, oils • DILUENT: dissolves the paint and adjusts its viscosity. e.g alcohol • PGMENT: gives the paint color and opacity. Natural clays, calcium,silicas etc 1. oil based • used prior to plastic paints • good high gloss finishes • not water soluble, brushes to be cleaned with turpentine 松节油 2. water based • most common today • durable and flexible • tools and brushes can be cleaned with water. -properties: • colour: resist fading, esp when outside in sunlight, red tend to be less stable, disappear • resist chipping, cracking and peeling, resist the effect of rain, air pollution and ultra0violet light in sunlight PVF2 are harder and more durable • gloss: matt • water based > flexible oil based paint
Glossary WEEK 7 • • • •
• • • •
Drip: to produce small drops of liquid Down pipe: the tube that connected with the flashing of the house, and let water drain down to the storm water system Vapour barrier: material used to prevent the passage of vapor or moisture into a structure or another material, thus preventing condensation within them. Flashing: a thin, impervious sheet of material placed in construction to prevent water penetration or direct the flow of water. Used especially at roof hips and valleys, roof penetrations, joints between a roof and vertical wall, and in masonry walls to direct the flow of water and moisture Gutter: a shallow channel of wood, metal, PVC positioned just below and following along the eaves of a building for the purpose of collecting and diverting water from a roof Insulation: material used to reduce the effects of heat cold or sound Parapet: the part of wall that extends above the roof level Sealant: an impervious substance used to fill joints or cracks in concrete or mortar. To exclude water and solid matter from the construction.