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Log Book - Week 7


" Detailing for Heat and Moisture" Detailing for moisture
 There a 3 conditions that must be met if water is to penetrate a building.
 1. An opening in the building.
 2. Water present directly at the opening.
 3. A force to push the water through the opening.
 If any of these conditions aren’t present the water won’t enter. However, if they are all met, water will enter the building.

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To ensure no water is able to enter the interior of the building, water needs to be kept away from openings when possible.
 An eave is an example of how water can be sent away from openings.
 Also overlapping tiles or weatherboards prevents water getting into openings(Ching, 2008), as shown to the left.

 Planned openings - Windows and doors.
 Unplanned openings - Deterioration of materials and poor construction.
 Silicone can be used as a sealant as it doesn't allow any water to get through.
 Gaskets are preformed shapes made from rubber. They also don’t allow any moisture through.
 However both of these techniques won’t last as long as the structure so they need to be reapplied. ket_chemical_resistant-1278407.html

A rubber gasket that prevents water from entering a building. The curved shape allows water to flow off the surface.

Neutralising the Forces
 Gravity - Use slopes and overlaps to carry water away from the building. This includes roofing, piping and paving.
 Surface tension and capillary action - Use a drip or a break
 Wind momentum - The wind can push drops into a building. To prevent this, more complex shapes are created for the water to flow. 
 Air pressure - There will be a tendency for the water from outside to be pumped inside from the change in pressure. Higher outside. Lower outside. An air barrier is put in to create a pressure equalisation chamber(PEC). This stops the tendency for the water to be pumped.


Wind pushing rain into a wall. The capillary break makes sure the water doesn't make it into the interior section of the house.

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 ! ! ! Detailing for Heat" Controlling heat - Conduction
 Thermal insulation:To reduce heat conduction.
 Thermal breaks: Made from low conductive materials such as rubbers and plastics. This reduces the heat transfer from outside to inside. It’s used to regulate temperature inside.
 Double glazing: Two panes of glass that a slightly separated. This air space between the two panes reduces flow of heat.

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A low conductive material used as thermal insulation between two steel beams.

Controlling heat - Radiation
 -Reflective surfaces
 -White painted roofs
 -Shade surfaces: Verandahs, eaves, screens or trees.
 Curtains and blinds inside the house aren’t as effective as the heat can already get through the glass before it is confronted. However curtains and blinds are a useful for controlling heat loss.

An example of how a tree provides shade for a house in the summer and allows heat in in the winter.


! Controlling heat - Thermal mass
 Masonry, concrete and water bodies are traditionally used for thermal mass. This is because they can trap heat in and it takes a long time for it to escape because of their density.
 The image to the left shows that because timber has a lot of air space heat can easily travel inside and escape the house.

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Controlling air leakage
 Similar to how to prevent water leakage. 
 If a building has an opening with a force pushing air through then the air will travel into the building and cause a cold draft if in winter. 
 Sarking(a building wrap) can be used as an air barrier to prevent air leakage. 

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Sarking on the outside of a building. This is permanent on the building and an exterior layer such as weatherboards will cover it.

Rubber - Properties
 Rubber can be both artificial and natural.
 Hard - to resist erosion
 Soft - to provide better seals
 Low fragility.
 High ductility when heated. 
 High flexibility, plasticity and elasticity.
 All rubbers are waterproof.(used as seals)
 1.5 x density of water
 Very poor conductor of heat and electricity.
 Very durable, can be recycled and cost effective


Artificial rubber is commonly used in tires on cars as it is able to be deformed without taking any damage from the weight of the car.{1}

Rubber - Types & Uses
 The most common uses of rubber are:
 -insulation (around electrical wiring)! -gaskets and control joints! -seals! -hosing and piping
 Rubber can be damaged by the sun and weather. Therefore sun exposure should be kept to a minimum.

Natural rubber being used as a seal or a stopper. It’s used to stop any moisture getting past as rubber doesn’t absorb moisture


! ! ! ! ! Plastics
 Thermoplastics - They are moulded when heated and set into a certain shape when cooled down. Plastics can be recycled and you are often prompted to recycle plastic on bins you see. Examples of these are:
 PVC - Piping
 Polyethylene - Used for insulation around metal pipes.
 Polycarbonate - Can be used in roofing or walling. Air spaces in between provide insulation.
 Perspex - Often used for skylights or as a replacement for glass because of it’s high plasticity and flexibility. "


Thermosetting plastics on the other hand aren’t usually recycled and are used in objects such as lego.

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A PVC water pipe. It’s waterproof properties combined with it’s light weight make it a perfect material for a pipe.

 Medium-low hardness.
 Medium-low fragility, however sunlight can make them brittle and potentially shatter.
 High ductility when heated.
 High flexibility and plasticity.
 Most plastics are waterproof.
 Low density.
 Poor conductors of heat and electricity however are good insulators.
 Depending on type and finish, they can be durable.

 The main purpose to paint a surface is to protect and colour. Clear paints are called lacquers or varnishes.

Paints - Properties
 Properties are hard to measure when talking about paints as environmental conditions can significantly alter the behaviour of the paint.{2}

-Fade when sunlight is directed onto them.
 -Exterior paints need to combat against air pollution and weather; including both sunlight and rain.
 -Flexibility - water based>oil based

Oil based: Used prior to water based paints.
 High gloss finishes can be achieved.
 Can’t be cleaned off the brush with water, turpentine must be used.
 Water based: More commonly used than oil based paints.
 Durable & flexible.
 Can be cleaned easily with water.

A before and after picture of a car’s bonnet. The faded paint is easy to see because of the colour compared to something like yellow paint which just turns to a creamy white which isn’t as noticeable.{3}

 ‘Arches are curved structures for spanning an opening, designed to support a vertical load primarily by axial compression.’ (Ching, 2008)
 Masonry arches are made out of wedge-shaped bricks or stone with the smaller of the wedge facing inwards. This is to allow the arch to gradually connect together at the top.

Domes! A dome is basically a 3D arch. It has the same characteristics as an arch in the way that the bottom bricks or stone slowly work their way into a central point. Each block relies on compressive forces to allow the structure to stand up. An example of a dome structure is an igloo.


A picture taken from the inside of a dome. Even though there is only half of the dome standing, the strength from the compressive forces is enough. This concept is similar to the block tower that we built in our first tutorial.




! ! Shell structures
 Shell structures are curved plate structures generally made out of reinforced concrete. It is more suitable for uniformly applied load as the thinness of the material creates weakness; it can’t bend very much.

A barrel shell structure is like an arch that has been pulled to make it longer. If the barrel is short it exhibits arch-like behaviour (Ching, 2008). The abutment prevents the lateral forces from the weight of the structure from falling in on itself.

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! ! ! ! ! Glossary
 Drip: An lip out of the side of a wall to make the water freefall to the ground rather than running down the wall.
 Vapour Barrier: A vapour barrier is an impermeable layer that blocks the flow of moisture in air through to the interior of the building.{5} ie. To prevent condensation(Ching,2008) Gutter: A container at the edge of a roof to collect or dispose of water.
 Parapet: A low wall or barrier enclosing a roof at the edge of the building.{4}
 Down Pipe: A pipe that carries water from the roof or gutter down to the ground or to a tank.
 Flashing: A strip of metal that prevents water from getting into an opening.
 Insulation: A layer in a wall that regulates temperature if there is a significance vary in outside and inside temperatures.
 Sealant: A material(silicone) that prevents water from getting through an opening."

A bridge parapet to prevent drivers from driving off the side of the bridge.


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Chimney flashing to prevent water from going down the opening between the brickwork and the roof.



 {2} modpaints_component2.html 


Ching, F. (2008) Building Construction Illustrated (4th ed.). Hoboken, New Jersey: John Wiley & Sons, Inc. (pp. 2.25-2.27, 7.02)

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