Superstructure design
15
SUPERSTRUCTURE DESIGN BTEC UNIT 6 February, 2012 John Fox, College of North West London 1
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College of North West London presentation; for the National Diploma in Construction
Transcript of Superstructure design
SUPERSTRUCTURE DESIGN
BTECUNIT 6
February, 2012 John Fox, College of North West London 1
DESCRIPTION OF THE SUPERSTRUCTURE
THIS INCLUDES; WALLS FLOORS ROOFS DOORS & WINDOWS TO KEEP
BUILDING WATERTIGHT
February, 2012 John Fox, College of North West London 2
WALLS Most external walls are built by brick
and block. Each can be defined as either high
or low density classification. This information is obtained from the
UK National Annex It also provides specification
guidance on other aspects such as;February, 2012 John Fox, College of North West London 3
Specification Criteria for Bricks/Blocks
Dimensions and Tolerance Configuration and format Density Compressive Strength Freeze/thaw resistance Active soluble salts content
February, 2012 John Fox, College of North West London 4
Specification Criteria for Brick/Blocks
Durability designations Water absorption Reaction to fire Bond strength Clay engineering and DPC bricks
February, 2012 John Fox, College of North West London 5
Concrete Blocks Been used since the 1930’s Made from aggregates such as breeze
and clinker Used mainly on the internal skin of cavity
construction Blocks also used for internal load bearing
walls and partitions Internal block walls will be finished with
plasterboard and a skim finishFebruary, 2012 John Fox, College of North West London 6
Cavity Construction Most domestic dwellings are
constructed in cavity construction Complies with building regs. Offers adequate resistance to the
passage of heat energy. Legislation ensures new buildings are
energy efficient with added insulation and sustainable building products.
February, 2012 John Fox, College of North West London 7
Cavity Construction Cavities reduces excessive moisture from
entering the property 2 ‘skins’ of wall connected with stainless
steel wall ties-450mm vertically- 900mm horizontally
Damp proof course used to prevent moisture from entering property
D.p.c laid at a min. of 150mm above ground level
February, 2012 John Fox, College of North West London 8
Cavity Construction There are 3 different types of cavities. Clear cavity- 102mm brickwork, 50mm
cavity, 100mm aerated block work & 40mm thermal board
Filled cavity-102mm b/w, 75mm cavity batt, 100mm aerated block with plaster
finish Partial cavity- 102mm b/w, 50mm cavity,
50mm insulation, 100mm aerated block with plaster finish
February, 2012 John Fox, College of North West London 9
Types of Cavities Clear cavity
Partial Fill
Fully fill
February, 2012 John Fox, College of North West London 10
Structural Stability In modern housing the stability of an
external wall is assisted by the bonding in of the flank & partition walls.
Additional stability is provided by the floor joists and the walls.
February, 2012 John Fox, College of North West London 11
Sound Insulation Building regs set the minimum
thickness for party walls. For solid walls 215mm is the min
width. For cavity construction 250mm is the
minimum width. Materials must be of high density Elevates airborne sound-voices, radio
etcFebruary, 2012 John Fox, College of North West London 12
Fire Protection Building regs demand external walls
of a 2 storey dwelling to have 30 minutes of fire resistance and the party wall to have 1 hour.
This enables any occupants to escape the fire within the time period.
Level of fire protection is achieved by the use of clay bricks & concrete blocks.
February, 2012 John Fox, College of North West London 13
Thermal movement In an average year a wall will expand &
contract due to heat, cold & moisture content.
Movement in the building must be allowed to occur, otherwise cracking will appear.
Expansion joints should be included on long runs of brick/block work eg 12m for b/w & 7m for block work
A compressible filler with a flexible mastic sealant is used for exp joints.
February, 2012 John Fox, College of North West London 14
Parapet Walls This is the section of wall which
extends beyond the height of the roof ‘Throated’ coping stones are bedded
onto the top of the wall with a dpc to prevent water ingress
A cavity tray should also be inserted in case moisture penetrates through the b/w.
February, 2012 John Fox, College of North West London 15
