Function of windows · Disadvantages of wooden frame windows: Regular painting or varnishing is...
Transcript of Function of windows · Disadvantages of wooden frame windows: Regular painting or varnishing is...
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Function of windows
Primary function of windows are to admit light and fresh air into the building.
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Design Features of Windows
1. LIGHT
2. VENTILATION
3. THERMAL INSULATION
4. ACOUSTIC INSULATION
5. SECURITY
6. DURABILITY
7. AESTHETICS
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1. Light Amount of light required
in any room depends on the activities that occur in the room
Minimum requirements for window area of a room is at least 10% of the floor area
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2. Ventiliation Rooms to a house to which ventilation requirements
apply are called “habitable rooms”
Habitable Room is a room with minimum floor area of 6.5m² that is used for living or sleeping.
There are two types of ventilation required for rooms
1. background ventilation _permanent
2. rapid ventilation – opening in window
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Background ventilation: This is ventilation provided by a permanent vent through an external wall.
Rapid ventilation: Provided by window openings
In habitable room the opening space must be at least 5% of floor area
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3. Thermal Insulation Primarily achieved
through the use of double glazing of windows and weather strip between the glazing.
Double panes reduce heat loss through glass
Weather strip prevents draughts
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4. Acoustic Insulation Usually solved by the
thermal insulation measures already taken.
Use of synthetic rubber seals around opens.
Sound insulation will be covered separately later.
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5. Security Depends on locking
mechanisms.
Some are designed to allow air circulation when the house is not occupied.
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6. Durability Windows should require
minimal maintenance
Teak timber window are resistant to rot.
Softwoods need regular maintenance
uPVC are more commonly used but are harmful to the environment.
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7. Aesthetics Fenestration is a term
used to describe the arrangement of windows on the façade (front) of building
Features to consider include pattern of windows, subdivisions of window, proportion of panes, recessing and projection of windows
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Other Features Fire Escape
In newly constructed houses windows must have a minimum opening width and height of 450mm.
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Other Features
Solar heat gain: is a term used to describe the warming of living space caused by sun shining through the window.
This is controlled at design stage: Position and size of windows?
Glare: is a term used to describe visual discomfort caused by excessive brightness.
Use of blinds and non-glossy surfaces with minimise this.
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Timber Casement Windows
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Weatherboard
(drip mould)
Sash top
rail
Side hung
casement
stile
Jamb
Sash
Bottom rail
Head
Vent
light
Transom
Dead
light
Mullion
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Top swung
casement
Side hung
casement
Joints Used Window frames are constructed using mortice and
tennon joints.
The sashes are constructed uing bridle/comb joints.
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A
B
C
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Top rail
Stile
Bridle joint
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Joint A
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Sill
Jamb
B
Joint B Mortise & Tennon
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C
Mullion
Transom
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Joint C Combed Joint
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A
A Head
Transom
Sill
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Head
Bone Sash head Glass
Sash bottom
Transom
Sash Head
Sash sill
Sill Rebate 2 Section A-A D. O' Dowd
Anti-capillary grooves are machined in the outer edges of the sashes to correspond with similar grooves in the frames. These prevent moisture penetration by capillary action.
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Sash bottom
Sash Head
Transom
Anti-capillary grooves
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24 Glazing sprig
Glass
Silicon Panel pin
Bead
Silicon or glazing beads secure the glass.
Putty was used before the arrival of silicon. D. O' Dowd
Opening sashes are usually hinged using two part alloy hinges. This allows the sashes to be easily removed for glass cleaning or for maintance.
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Plan view of window head
Open sash
Silicon
Glass
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Advantages of wooden frame windows:
Made from renewable resource.
Aesthetic.
Easily painted to a variety of colours.
Generally cheaper than other window materials such as aluminium and u-PVC.
Good insulators.
Available in both hardwood and softwood.
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Disadvantages of wooden frame windows:
Regular painting or varnishing is required.
Softwood windows are prone to rotting over a 10-20 year life cycle.
Hardwood windows have a tendancy to warp if the wood in not seasoned correctly.
Difficult to seal wooden window sash openings. This may lead to draughts.
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