student l1 cavity wall construction
TRANSCRIPT
Cavity Walls
Construct Cavity Walling
Student Copy
Name ………………………………...
What is a cavity wall?
A cavity wall is made up from:
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•
•
Cavity wall construction
50mm minimum width of air gap
Section through a cavity wall
Solid Walls can let dampness into buildings.
Section through a solid wall
Why do we use cavity walling?
Cavity Walls were
originally
introduced to
prevent ________
penetration.Section through a cavity wall
Problems?• Weakness: Two slender half brick / block skins
are not as _______ as a one brick thick solid
wall. How can this Kind of walling be strengthened?
The use of ______ ______ Ties
_______ ______ TiesThe walls are supported and tied into one another by means of specially designed metal ties called ‘_______ ties’.
Wall Ties are made from __________ steel
Cavity Wall TiesProblems can occur when bridging the cavity, such as
_______ penetrating from the outer leaf to the inner leaf.
Section through a cavity wall
Common Faults
Wall tie spacing’sBuilding Regs state wall ties must be positioned _____mm vertical ______mm horizontal (100mm cavity) and no more than 300mm vertically on un-bonded reveals.
Bridging the cavity can create problems.
Preventing ______ Transfer.
The ______ DPC prevents water crossing along the top of the air-brick liner.
Section through a cavity wall
Typical components needed for bridging cavities at openings.
Keep the cavity clean.Mortar droppings can
gather on wall ties and at
the bottom of the cavity
creating a ________ for
water to pass through to
the inner leaf.
Section through a cavity wall
Clean Cavities
Keep the cavity
clean to
prevent ______
penetration
Section through a cavity wall
Ensuring Cleanliness• _______ Hole
Ensuring Cleanliness• _________ _________
Wall construction below ground level
Cavity walling below ground level:-
• Cavity wall formed with two leafs of
common bricks. The external leaf will revert
to facing bricks __ course below ground level
to allow the bricklayer to ensure that bond is
worked out
Broken BondIf Broken Bond can not be avoided the piece should be
placed in the centre of the wall, or against the reveal.
No cut should be less than __ _______
If bastard sized window and doors are used then the
piece is better placed _________ the opening if possible.ANY CUT SHOULD ALWAYS STAY IN THE SAME
POSITION