Construction Tech Flashcards
What does the shape or size of a building affect its exposure to?
Solar gain/heat loss, wind pressure and exposure to rain
What are the types of wind pressure and how do they work?
Windward pressure (positive) exerts a pushing force onto the walls and roof of a building
Leeward pressure (negative) exerts a pulling force onto the walls and roof of a building which results in suction, vortices and eddies.
Which building shapes create the highest potential wind pressure?
Square or flat as they offer the greatest resistance.
Curved surfaces reduce direct impact and allows the wind to flow around them, however, this can result in vortex shedding and vibration.
What is the potential impact of solar exposure on a building?
UV light can cause degradation to materials. Materials which are particularly prone to this are timber, paint and plastic. Whilst they can be treated to reduce the impact with additives or stabilisers, consider the locations of these items.
How can the exposure of walls to UV light be reduced?
The eaves overhang can be increased to provide additional shading. This also has the benefit of reducing solar gain and protecting the elevation from rain, including and acidic or alkaline properties which may cause degradation to the element. Rain can also cause discolouration and eventually freeze thaw.
When did ground bearing solid floors begin to be sealed with concrete?
From around 1880
What are solid floors prone to?
Heat transfer, moisture ingress and surface condensation. However, these are less likely with insulation and a damp proof course.
Where is the most likely area for a thermal bridge between the floor and wall?
In a corner as there are more interfaces between elements and surface exposure.
What is the typical construction of a suspended floor?
Joists, traditionally timber but possibly also concrete, supported by the external walls with a gap between them and the ground below. This could either be through joist hangers or built into the walls. The joists are then overlaid with other materials to form the floor, such as timber or concrete blocks. There may or may not be dwarf walls to support the joists and the space should be ventilated to allow air flow.
What are the potential issues with a suspended floor?
The air movement below can be draughty and lead to significant heat loss. They can be insulated making them more airtight but are still prone to air filtration.
What do Building Regulations require walls to be capable of?
Not cracking, preventing moisture ingress and retaining air tightness
