The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Answer for question 01a
House 10 is a terraced house which is part of large terrace of six units in one
raw, including some Victorian type architectural features such as; high pitched
roof made of slates, high gable walls in front and rear elevations, Big Sash
Windows (open by sliding the window up), Outer brick walls, gable wall end
with corbelled brick work etc.
• High pitched roof
The high pitched roof made of interlocking fibre cement slates is plays a major
role for the better view of the house and provide to allow water runoff and a
deterrent to frozen perception such as snow and ice. The snow and ice will slide
down the slates as it melts instead of penetrating the roof underneath the
slates. The roof fully constructed with timber frames including purlins, ridge
plate supporting timber rafters. The plain ridge tile has been fixed to cover the
ridge and top edge of the slates in top raw to avoid the water leaking through
the slates. There is eves exposed to the elevations and the joining of the gable
walls with roof has fixed with flexible metal flashing to cover the water leak
through the joint. The wooden facia board is fixed to the bottom end of the roof
for facilitate the fixing of gutters.
• Gutters and down pipes.
It assumes to be half round UPVC gutters are installed with UPVC down pipes
and appropriate fittings. In front elevation, the main roof water has collected to
the high level gutter line and goes through the running outlet and down pipe
directed to the low level gutter line. Both the high and low level, collected
water again goes away from valley gutter running outlet through the down
pipes fixed to the both corners near to roof valley to the drain manholes
situated in the ground. Architecturally the positioning of down pipe is
symmetrical to the house 10 and 11 elevations and positive effect to the
appearance.
• External walls.
The external wall of house 10 consists of the load bearing cavity walls with
block work inner leaf and brick outer leaf. For the external features, the outer
skin of the brick work is considered. The type of the bond identifies as common
stretcher bond. The width and profile of the mortar joint has impact on the
appearance of brick work. The weathered mortar joint is more appropriate.
Wall ties in cavity wall achieve the strength and the prevention of water
penetration to the inner leaf of the wall. The galvanized steel lintels on the top
of window and door openings are used. The door and window openings are
symmetrical in the front and rear elevations of house 10 and 11. The wall ends
are seems to be moulded. The height of the external wall is match with the
appearance of the house and gable walls.
K.P.Prabath Chammika Yasapala1003754
Page 1 of 18 F103TEC 0012010/11
The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Continue Answer 01a….
• Gable walls.
The high gable wall with outer skin brick work in front and rear elevations are
added a gigantic view of the house and reflects the typical characteristic of
Victorian house. The top end of the gables are decorated with coping brick work
and separated the ordinary stretcher bond outer skin brick work with a grove
for damp proof course and the end of grove decorated with moulding. The door
and window openings are decorated with a thin groove or moulding for better
appearance. The high supporting cross walls (gable walls) are appeared to be
finished with outer skin brick work and top pre-cast concrete coping.
• External windows.
Big Sash windows are appeared in front and rear elevations made by
aluminium powder-coated frames with double-glazed units (open by sliding the
window up). The double glazed will reduce the thermal effect and aluminium
frame is more durable and easy for the fabrication. The standard sill heights
are maintained in ground floor and the large window achieves the lighting and
ventilation requirement as well. The top moulding disturbs to the flow of rain
water along the window sash and the sill is active to prevent the water flows on
the wall surface under the window.
• External doors and porch area.
The main entrance door, store room door and kitchen out door are the main
external doors used as access to the house and store room made by wooden
framed with doubled glazed units. The size of the main entrance is larger than
the other internal doors. The providing of top light and double glazed unit is
also maintaining a weather barrier. The threshold and weather mouldings are
protect the door from the external environmental effects especially from the
water. The small porch is available on main entrance and helpful to cover the
entrance to serve as a shelter for weather effects such as rain, direct sunlight
and wind. The floor assumes to be finished with mat finish tiles in the porch
area.
• Ground elevation.
The step down of ground elevation from house 09 to 10 has added an
attractive architectural view to the front and rear elevations and highlighted the
different roof elevations with high supporting cross wall helps to identify the
separate units of 09 and 12 and be assumed that the original ground elevations
with gradual slope down the site towards south east has well utilized.
• Landscaping.
It seems to be a wooden fence has separated the units and easy access is
available from the roads. Provision for parking area is located in front of the
house and the small gardening area is available.
K.P.Prabath Chammika Yasapala1003754
Page 2 of 18 F103TEC 0012010/11
The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Answer for question 01b.
RIDGE DETAIL
DETAILS OF PITCHED ROOF
Source: CEM –Building Technology 1
K.P.Prabath Chammika Yasapala1003754
Page 3 of 18 F103TEC 0012010/11
The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
DETAIL OF RAIN GUTTER
K.P.Prabath Chammika Yasapala1003754
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Continue Answer 01b…
DETAILS OF EXTERNAL CAVITY WALL
K.P.Prabath Chammika Yasapala1003754
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Continue Answer 01b….
DETAILS OF GABLE WALL
K.P.Prabath Chammika Yasapala1003754
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Continue Answer 01b….
DETAILS OF ALUMINIUM WINDOW
Source: Esmond Reid – Understanding of Buildings.
K.P.Prabath Chammika Yasapala1003754
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Continue Answer 01b….
DETAILS OF DOOR FIXING
Source: Esmond Reid – Understanding of Buildings.
K.P.Prabath Chammika Yasapala1003754
Page 8 of 18 F103TEC 0012010/11
The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Answer for question 02
The roof, External walls, floor, doors and windows are the main exteriors of the
house. This envelope is the environmental separator, generally between the
inside and outside of a building including the ground. The proper designing,
construction techniques, proper materials and proper maintenance can increase
the durability and longevity of the building and as well as the durability of
exteriors. The durability of the material which is used for construction is very
important for the life span of the building. A building's lifespan has mostly
depended on the structure of the building and the exteriors should have to be
tightly covered the structure from the effects of external environment. The
effective control of the following external climatic or environmental factors by
the exteriors achieves the durability and longevity of the house.
• Water/moisture
Water /moisture enters building’s exteriors due to condensation, from rain
or melting of snow and is responsible for the swelling and rotting of some
organic materials such as wood and the corrosion of metals. It is involved in
the freeze-thaw deterioration of porous materials.
• Air pressure/ wind
The wind will decay the surface of the materials and the physical damages
by removal of part of building and wind will cause air leakages. Air leakage
is a major cause of problem in exterior walls, cause dampness by driving
moisture into building fabric and excessive heat loss from the interior.
• Solar radiation
Ultraviolet radiation from sunlight affects the durability of organic materials
such as polymers, wood and bituminous materials.
• Temperature
Due to the variation of temperature, building materials change volume and
if change in volume is not allowed for in the form of movement control
joints and it will form cracks and thereby affecting the durability of the
component.
Roofing system
The proper pitched roof determines the durability and longevity of the house
with appropriate water proofing system. The selection of pitched roof (Pitch
around 350 - 400 minimum) and the materials such as; the roof covering
materials, wooden rafters, battens, damp proof membrane, gutters, down pipes
and fascia board has to be appropriate for the design function, detailing for the
application and the proper installation is essential. Especially for the rain, roof
is the hardest tested surface in wet weather. Water proofing is necessary for
the pitched roofs with continuous DPM and the edges of the high supporting
cross walls must be covered with flexible metal stepped flashing.
K.P.Prabath Chammika Yasapala1003754
Page 9 of 18 F103TEC 0012010/11
The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Continue Answer 02….
The overlapped fibre cement slates must be nailed to battens for the
unmovable position and the curvature determines the broken capillary path.
The ridge tiles must be detailed and installed properly overlapped with the top
raw of fibre cement slates. The treated timber has to be used for the roof
structure and it does not attacked by uncontrolled damp and fungal attacks.
If there is no any water leakage to the inside of the house from roof means the
proper material selection, design and workmanship achieved. The proper and
regular maintenance is essential for roofs and concentrate for the collection of
the rain water and got away immediately through the down pipes. If it were
just left to be shed from the edges, it would soak and damage the external
wall. Eve of the roof helps to cover the external wall from direct storm water.
(Refer Figure 2.1 in Appendix A for details of pitched roof water proofing).
External walls
The external walls involve to providing the environmental control between the
external and internal climate of the house and is required to support the
imposed and wind loads of the roof and floor and transfer its own combined
loads safely to the foundation. The external walls play a major role for the
durability and longevity of the house. The selection of appropriate materials
according to the climatic effects, construction methods to resist water
penetration through the envelop, controlling of expansion of walls (maintaining
expansion joints and contraction joints), controlling of capillary action on the
external surface of the wall and detailed solution for the erosion are sought to
be address.
The walls can be segregated as the permeable, semi permeable and
impermeable. For this construction, the semi permeable is used as the cavity
wall with block work inner leaf and brick outer leaf. Water penetrates through
the bricks, the cavity allows flowing down the water and coming out through
the bottom weep holes. The non corrosive ties must be embedded within the
horizontal mortar of the joint in order to provide adequate restrain to each leaf
of the wall. The type of bond is stretcher and the type of mortar joint is
affected by the variation of temperature. So the allowable expansion is
necessary. The providing of insulation is for the thermal comfort inside the
building and the block work must be properly constructed as per the
performance requirements. The opening of the walls must be properly sealed
after the fixing of door or window to avoid water penetration through these
gaps. Mastic fillers should be used. The maintenance of the external brick face
gains the durability of the external wall. Especially the mortar joints should be
maintained and inspected. The top of walls should be properly covered in Gable
walls and with cobbled end.
K.P.Prabath Chammika Yasapala1003754
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Continue Answer 02….
Solid ground floor slab
The type of the ground floor is very important part of a house for the durability
and its longevity. The ground bearing insitu concrete slabs and suspended
timber floors are common in small house construction. For both, the damp
proofing system, firm base and the finished level should be properly detailed
with appropriate construction method. To address the heat loss, insulation
material can be placed on the damp proof material.
Removing of top soil and filling with appropriate filling material to the required
thickness with full compaction using mechanical hammers up to the dry even
top surface for the laying of concrete slab. The thickness of hardcore and the
concrete slab is minimum 100-150 mm. The greater mass of concrete will offer
a greater resistant to rising moisture. The ground water table must be
considered when the slab designing and the proper detailing is sought for the
damp proofing system. The more thickness slabs, (more than 100 mm thick)
the reinforcement mesh is required to avoid the shrinkage due to weak subsoil
condition. For the insulation can be placed to reduce the heat loss either before
casting the ground slab on the 50 mm thick concrete screed or on the ground
slab covered with 50 mm thick screed. Both methods can be used and after the
casting of ground slab. We have to select the appropriate and economical
system for the above application.
(Refer figure 2.2 and 2.3 in Appendix B & C for the details of ground bearing
concrete slab with damp proofing system)
Doors and windows
The openings must be fulfil the following functions such as; access, weather
protection, appearance, ventilation, lighting, view, privacy and security.
Construction methods used to resist water and wind penetration through door
and window opening is essential for the durability of the building. The wooden
door frame or aluminium coated window frame fixing to brick work, threshold
and sill details, the seal between door, window frame and glass and draught
excluding devices can be fitted in the gap to eliminate the flow of air is
essential for proper detailing of door and window. Double glazed units will
reduce the heat and sound from the external environment as well. Weather
protection must be provided for timber doors by non absorbent finish and a
weather board fitted across the bottom. For windows also the same applicable
for weather exclusion. It is important to reduce the water streaming down the
window face. Head moulding and window setback within the wall depth help to
fulfil the above requirement.
K.P.Prabath Chammika Yasapala1003754
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Answer for Question 03
For the determination of form and layout of the building, consideration of
geographical, climatic, geological and environmental factors is necessary.
These are the external environmental influences.
The selection of appropriate location, type of the building, shape of the building
and other requirements such as; selection of appropriate materials, type of
foundation etc. are mostly depending on the environmental influences.
The following environmental influences should be considered for the
determination of the building’s form and layout.
• Air and pressure
• Wind pressure (natural ventilation)
• Daylight
• Sunlight and passive solar gain
• Sound
Air and pressure
The selection of appropriate location for the better living, the air purity and the
altitude sought to be considered. Avoiding of air polluted areas and higher
altitude (higher elevations) should be considered. The distance between such
as industrial areas and thermal power plants hectare to be care when the
designing of residential complex. For the breathing process, the contain of
oxygen in fresh air should be as per required percentage (21%). Especially the
carbon dioxide percentage (0.03%) has to be monitored because it causes the
global changes and threat to the whole living creatures. The blood can function
normally at atmospheric pressure at sea level. So the healthy altitude should
be considered (250 – 750 m from sea level).
Wind pressure (natural Ventilation)
Wind direction and the wind speed (strength) are acquiring the natural
ventilation for the building. For the satisfactory standards of air purity and
comfortable atmospheric condition within a building the above two properties of
the wind is highly required.
For the determination of form and layout of a building, the following
characteristics of wind should be considered.
• Wind pressure.
• Aspiration
• Perflation
• Stack effect.
K.P.Prabath Chammika Yasapala1003754
Page 12 of 18 F103TEC 0012010/11
The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Continue Answer 03….
Wind Pressure
The front face of the building can be gain pressure due to wind (windward side)
and other sides gain the suction (leeward side) effect. The centre of the face
has high pressure and the edges of walls comparatively low. Suction is
higher in edges and corners. Also roofs are more effected due to above high
speed wind currents. The pitch of the roof is an important factor in windy
conditions. The low pitch roofs below 150, there is maximum suction and
negative pressure and the pitch above 350, positive pressure on windward
direction and suction on leeward side. So the determination of pitch of a roof in
windy condition is highly important for the stability of a roof.
Aspiration
Wind current passes a building through the right angle across the top of a
ventilation shaft, air is move up from the shaft and fresh air fills the rooms
below. This is additional to the upward movement of warmed air when fire is
burning.
Perflation
Perflation can be maximized with identification of correct wind direction of the
location. The cross ventilation is gaining more benefits of natural ventilation.
Wind will enter to the building by windward direction through openings or inlets
and flow through the outlets in leeward direction due to suction effect. The flow
of air is diverted up and over the building and side windows can be either inlets
or outlets. The windows are used to control the volume, velocity and direction
of air flow and must be capable to adjust according to the requirement of the
ventilation.
Stack effect
Stack effect also replace the fresh cool air into a building as natural ventilation.
Low dense warm air displaced by cool heavier air as a vertical current and
enters through the openings at low level and warmer air will escape through
the openings at higher level. This process is highly depend on the speed of air
movement, temperature difference between inside and outside of the building,
level difference of higher and lowers openings and the area of the openings.
Daylight
Day light is the “natural lighting”, the sky provides in day time (not direct
sunlight) without glare into a building through the holes in external fabric such
as; windows, roof lights, etc from the right direction. For the design criteria
“Daylight factor” is very important and it is a measure of daylight at a point in
a room relative to the light coming from whole sky. Day light is important to
the health of occupants and there are typical recommended minimum daylight
factors for all types of buildings. Fenestration sought to be designed according
to the maximum benefit of daylight with the shape, position, size and glazing-
K.P.Prabath Chammika Yasapala1003754
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
Continue Answer 03….
-materials for window and roof openings in the building. The interior colour and
finishing, flooring material (gloss tiles) and positioning of mirrors can helpful to
increase the daylight factor by reflection as well.
Sunlight and passive solar gain
Sunlight is the direct rays appeared from the sun through the atmosphere to
inside the building through the windows and openings. The openings and the
layout of rooms should be designed in residential building, to be allowed
sunlight to enter to the living room, kitchen and bedrooms for at least one hour
per day for 10 months of the year. Direct sunlight in a building can cause
intensive glare, overheating and fading of surface colours. Shading and
reflective devices include trees, overhangs, louvers, blinds, shades and curtains
are helpful to reduce the glare. Using of double glazing units with reflecting
outer face can be minimizing the heat transmission through the window
opening.
Careful orientation of buildings is vital for passive solar gain. The permanent
shadows should be avoided by using their major axis of the buildings from
north-east to south-west, or south-east to north-west. The roads also try to
align with east-west direction and minimizing over shading by locating taller
buildings to the north side or to the south of road junctions. For layout of
buildings can reduce the over shade of open areas, always locate shorter
buildings to the south and taller buildings to the north as well. The internal
form of house shall be oriented the most frequently used rooms facing south
and least used rooms facing north. Especially living room has to be located in
south and bathroom and utility rooms shall be in north.
Sound
Sound is a form of energy can be created by series of pressure waves in air or
other medium. Air, water, wood or metal is common sound transmitting
mediums. The outside unwanted sound (noise) can be transmitted through the
external fabric of the building by Airborne, Impact and flanking sound
transmission. The controlling of noise inside and outside of the building is
necessary for better living condition of the people. From the external noise,
nuisance is most often caused by motor traffic. The type of external walls, floor
and types of glazing of door and windows has to be considered to reduce and
control the outside noise transmission to the building. Sound absorption
reduction of echo is necessary for better listening conditions in small houses.
The block and brick cavity walls double glazing units and separating of floors
are helpful to reduce noise. The location of the building and the layout should
be very important to reduce the external noise as well.
K.P.Prabath Chammika Yasapala1003754
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
APPENDICES.
APPENDIX A
FIGURE 2.1 – Some waterproofing principles of pitched roof.
Source: Esmond Reid – Understanding of Buildings.
K.P.Prabath Chammika Yasapala1003754
Page 15 of 18 F103TEC 0012010/11
The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
APPENDIX B
FIGURE 2.2- Damp proof membrane below ground floor slab.
Source: Mitchell's –Introduction to Buildings (4th Edition)
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
APPENDIX C
FIGURE 2.3 – Thermal insulation to ground floor slab
Source: Mitchell's –Introduction to Buildings (4th Edition)
K.P.Prabath Chammika Yasapala1003754
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The College Of Estate Management Building Technology 01
University of Reading Bsc. ASSIGNMENT 01 Module Code: F103TEC
REFERENCE:
CEM (2008) Building Technology 01, Finishes, paper 1387 page 13, Reading:
College of Estate Management.
Derric Osbourn and Roger Greeno (2007) Mitchell's' Building Series,
Introduction to Buildings (Fourth Edition)
Esmond Reid (2005) Understanding Buildings
Total number of pages: 14
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