L1 Cavity - Air Bricks and Ties

Why do cavity walls need to be air tight?

• To control carbon emissions

• To keep vermin out

• To hold the insulation in place

• Prevent condensation

Identify this brick

• Filter Brick

• Flowing Brick

• Air Brick

• Core Brick

Why are air bricks used on cavity walls?

• To provide air flow to the cavity

• To provide air flow to suspended floors (dead spaces)

How many bricks in a square metre?

• 40

• 50

• 60

• 70

How many blocks in a square metre?

• 5

• 10

• 15

• 20

What material is a wall tie made from?

• Mild steel

• 
  Galvanized steel

• Reinforced steel

• 
  Stainless steel

What is the minimum distance a wall tie bedded?

• 25mm

• 35mm

• 40mm

• 50mm

What is the centre of a wall tie called?

• Drip

• Bend

• 'W'

• Slip

What is the maximum distances wall ties should be spaced?

• 400mm horizontal

  400mm vertical

• 450mm horizontal

  900mm vertical

• 500mm horizontal

  800mm vertical

• 300mm horizontal

  800mm vertical

What type of block should be used to improve the thermal efficiency of a cavity wall?

• Aerated lightweight

• Dense

• Trench

• Hollow