timber 2

Question 1

name two ways of classifying timber in terms of its durability

Answer 1

BS and TRADA

Question 2

what are the 5 attacks on timber?

Answer 2

insect and fungal
photochemical 
chemical 
thermal 
mechanical

Question 3

what are the 3 different rots (fungal attack)?

Answer 3

dry rot- moisture at 20%, when seen on surface, internal is destroyed
wet rot - moisture 50%
soft rot- timber + ground water

Question 4

name the different insect attacks

Answer 4

woodworm- on furniture
longhorn beetle- holes are 10mm diameter
dead watch beetle- destroys structural element
powder post- turns timber into powder
shipworm- makes tunnels

Question 5

describe photochemical attack on timber

Answer 5

only affects the surface of the timber

Question 6

describe chemical attack on timber

Answer 6

alkali causes decay (nail sickness- corrosion of fastening)

Question 7

describe thermal attack on timber

Answer 7

causes loss of strength

Question 8

describe mechanical attack on timber

Answer 8

creep reduces stiffness

Question 9

how is timber in fire?

Answer 9

timber is resistant in fire (can just cut off and use)

the heat produces gases

Question 10

how can preservatives be added to the timber?

Answer 10

in the coating, glue or through pressure treatment