Assignment 2: Site Study (Roofing system)
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Chong Khei Mink
0322359
Construction and Technology
Assignment 2: Site study
Group members
-Yuki
-Stella Chung
-Lulu Chen
-Jia Min Koh
The site we have chosen for this site study is my house in Slim River. My group members followed me back to my hometown once just to study the site and to record the observation. I've chosen roofing system as my part.
Roofing system
Introduction
Based on my studies about roof for this site study, I realized that there are various kind of roof structures in different context purportedly designed to be climate responsive. For example, there are specific roof to withstand low temperature and snow falling.
In our country, our residential building which is tropical architecture, expose to strong sun radiation and high rainfall throughout the year, thus, we need specific roof system which provide heat insulation.
For tropical context, aluminum foil and bubble foil are one of the most known reflective type of insulation. Bubble foil which is often considered as a type of aluminum foil too, is also used though not very common. Bubble foil provides a more efficient heat insulation. It is mainly used in higher budgeted buildings due to its high cost. However, aluminum foil is normally used as sarking, which essentially acts as radiant barrier to reflect the sun heat and acts as vapor barrier. Because, without the aluminum foil, the warm and humid air will come in contact with cool air-conditioned surface would create condensation which in the long term can affect the integrity of roof structure. In case of timber structure, it will eventually rot. Furthermore, aluminum foil is ideally used together with rockwool or bubble foil to reduce heat more substantially. Rockwool and glasswool are materials that can be applied as loose fills or blanket insulation.
Roof layers from framing to roof tiles (Underlayment)
Roof terminology
Whether driven by hand or pneumatic nailers, nails should be driven so heads lightly touch the tile but not so tight as to risk cracking tiles.
Because of the longevity of a tile roof, some contractors use copper or stainless-steel roofing nails. No. 8 or 9 stainless-steel or brass screws also work well and are sometimes used in high-wind regions.
Based on the information I got from the contractor who built the residential building on our chosen site, he stated that even though in theory, all tiles with holes should be nailed but when comes into practical, laying the tiles on the purlins one by one, overlapping each other, they only nailed the first row and the last row of the tiles. Because it will be more flexible when comes to repair. Tiles can be replaced easily if it's not nailed. Furthermore, mortar is not added in the gap of the tiles.
0322359
Construction and Technology
Assignment 2: Site study
Group members
-Yuki
-Stella Chung
-Lulu Chen
-Jia Min Koh
The site we have chosen for this site study is my house in Slim River. My group members followed me back to my hometown once just to study the site and to record the observation. I've chosen roofing system as my part.
Introduction
Based on my studies about roof for this site study, I realized that there are various kind of roof structures in different context purportedly designed to be climate responsive. For example, there are specific roof to withstand low temperature and snow falling.
In our country, our residential building which is tropical architecture, expose to strong sun radiation and high rainfall throughout the year, thus, we need specific roof system which provide heat insulation.
For tropical context, aluminum foil and bubble foil are one of the most known reflective type of insulation. Bubble foil which is often considered as a type of aluminum foil too, is also used though not very common. Bubble foil provides a more efficient heat insulation. It is mainly used in higher budgeted buildings due to its high cost. However, aluminum foil is normally used as sarking, which essentially acts as radiant barrier to reflect the sun heat and acts as vapor barrier. Because, without the aluminum foil, the warm and humid air will come in contact with cool air-conditioned surface would create condensation which in the long term can affect the integrity of roof structure. In case of timber structure, it will eventually rot. Furthermore, aluminum foil is ideally used together with rockwool or bubble foil to reduce heat more substantially. Rockwool and glasswool are materials that can be applied as loose fills or blanket insulation.
Roof layers from framing to roof tiles (Underlayment)
- Chicken wire
- Aluminium foil - used as sarking, which essentially acts as radiant barrier to reflect the sun heat and acts as vapor barrier
- Rock wool - fire resistant, durable, heat insulation
- Purlins - as a form of support for rafters and are horizontal structural members in a building, architecture or structural engineering
- Rafter- one of a series of sloped structural members (beams) that extend from the ridge or hip to the wall plate, downslope perimeter or eave, and that are designed to support the roof deck and its associated loads
- Ridge End Cap – Used for capping horizontal ridge ends. It overlaps on both Left and Right Verge Tiles to provide a good finish
Roof terminology
- Ridge tile - Used on horizontal/main ridge formed by 2 roof slopes. Internal width 220mm. Coverage 3 pieces/metre
- Verge tile- Provide water-tightness to roof edge and lends a solid appearance
- Top fixture
- End band - Starter tile at eaves area of a roof hip. It gives aesthetic finishes and water-tightness
Truss terminology
- Ridge tile-Used on horizontal/main ridge formed by 2 roof slopes. Internal width 220mm. Coverage 3 pieces/metre
- Apex - the highest point of the truss
- Webs -a short aluminum which runs from the bottom the bottom chord to the top chord
- Purlins- as a form of support for rafters and are horizontal structural members in a building, architecture or structural engineering
- Eaves board (Fascia) -an architectural term for a vertical frieze or band under a roof edge
- Overhang- the top chord which extends from the wall
- Wall plate
- Collar beam
- Nail plate
- RC wall- to support the load of roof structure
A Sloping Flat Truss is used to create a vaulted ceiling. It may be top or bottom chord bearing. This truss has parallel chords, both of which slope at the same angle, with a vertical post at each end.
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| Triple Howe Truss
Howe Trusses are meant to span up to 36 feet and a Double Howe is rated for as much as 60 feet. The longest Howe Truss design is the Triple Howe, and it is designed for spans ranging from 54 feet to 80 feet in length.
How clay roof tiles are secured to the roof
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There's few ways on how to secure the clay tiles on the roof. For the chosen roof, nails are used to secure the tiles .Nails are the least expensive and most common method for attaching concrete and clay tiles. Tiles can be nailed either directly into the roof sheathing or tiles with lugs can be nailed to battens.
Corrosion-resistant nails must be minimum 11 gauge, with 5/16 -inch heads, and long enough to penetrate the sheathing by 3/4 inch—typically 8d nails.Whether driven by hand or pneumatic nailers, nails should be driven so heads lightly touch the tile but not so tight as to risk cracking tiles.
Because of the longevity of a tile roof, some contractors use copper or stainless-steel roofing nails. No. 8 or 9 stainless-steel or brass screws also work well and are sometimes used in high-wind regions.
Based on the information I got from the contractor who built the residential building on our chosen site, he stated that even though in theory, all tiles with holes should be nailed but when comes into practical, laying the tiles on the purlins one by one, overlapping each other, they only nailed the first row and the last row of the tiles. Because it will be more flexible when comes to repair. Tiles can be replaced easily if it's not nailed. Furthermore, mortar is not added in the gap of the tiles.
Roof Tiles Used
-MONIER clay brick tiles
Specification 
Length - 420mm
Width - 330mm
Weight (per piece) - 4.3kg (+/- 0.1kg)
Joints
For steel rafter, aluminum hollow and aluminum channel are used.
For purlins, aluminum hat channel , aluminum C channel and aluminum Z channel are used.
Connection
The apex plate is apply between the top chord and king post. Then bolted it with 6 screws.
Sketches
End
