WorksheetsDampness in Building
Total questions: 10
Worksheet time: 5mins
Why some timber can float on water for some time before it sinks?
Voids are not fully saturated
Solid mass of timber is quite low
Voids are readily filled with water
Solid density of timber is quite high
How can the dampness find its way to the floor through the substructure?
Action of rain
Condensation
Exposed tops of walls
Raising moisture from ground
Which of the following is NOT an effect of moisture on building materials?
Expansion
Contraction
Efflorescence
Timber damage
Which of the following is NOT a method of water entering during construction?
Poor site control of storage of materials
Residual water used in nearby settlements
Inadequate protection of partially built structures
Water used for mixing of mortar, concrete and plaster
What is formed when water and glass are in contact?
Meniscus
Hydration
Pores and voids
Cohesion forces
Which of following is NOT a measure to prevent rotting of windows and doors?
Use of thicker glass
Use of anti-capillary grooves
Inward opening of external doors
Use of sealant around frame edges
Which is NOT a measure to prevent water from penetrating roofs?
Spaces are made bigger between tiles
Adequate ventilation of the roof space
Tiles are curved to reduce capillarity between them
A minimum pitch, usually 35°, to reduce water absorption
What causes the drawing up of water through a narrow tube or channel in capillarity or capillary action?
Gravitational forces of the water molecules
Shear forces between the glass and water molecules
Adhesive forces between the glass and the water molecules
Compressive forces between the glass and the water molecules
Which of the following is a porous material?
Iron
Glass
Plastic
Concrete
Which of the following is NOT a porous material?
Glass
Mortar
Timber
Sandstone
