The dissertation will comprehensively discuss the effectivity of insulators in stabilizing indoor-temperature as an outcome of controlling heat gain and heat loss particularly with brick-clad structures that are constructed either with concrete form or timber frame materials for its walls. The objectives of the dissertation are as follows: a. To determine the insulation properties of bricks; b. To compare and contrast ICF wall construction over timber-framed construction; c. To measure the effectivity of insulators to control heat-gain or heat-loss.
The dissertation will delve into the qualities of brick as a building material and at the same time discuss the manner by which cladding is installed. Why is the conventional method of brick laying more appreciated over the faster new system of installation? Through literature readings, we shall decipher why bricks continue to be the material of choice for many residences. Included in the literature review is the relevance of brick as a building material to the present trend in design and construction.
The structural capacity of bricks will be analyzed and the proponent will discuss the reason behind its shelving in favor of the more robust reinforced concrete (pre-stressed and post-tensioning system) and structural steel. The dissertation will also discuss the concept of brick-cladding and rate its relevance to the construction of buildings. Moreover, we shall be determine whether application is better for ICF wall construction or best for timber-framed buildings. Also, we shall try to explore the different insulation presently used and the degree by which it affects the total thermal environment.
Because of weather extremes, temperature plays a very important part in the development of materials that seek to solve the perennial problems of heat-gain in summer and heat-loss coefficients in winter. Vital segments of this dissertation include experiments conducted that would clarify the data presented in various handbook and manuals. A statistical test method was adapted to quantify known data while results were interpreted based on scientific information. The first two objectives shall be resolved through the use of qualitative data only, which was obtained from available literature.
The last objective of this dissertation will be resolved through an improvised scientific experiment with the data interpreted through statistical testing. Finally, recommendations were discussed on the resolve of nagging issues of energy conservation and the effects of the manufacture of construction materials to ecological balance and the global warming phenomenon. II. Review of Related Literature The Development of bricks In prehistoric times, man’s quest for durable shelter from weather elements leads them to find comfort inside caves.
Once domesticated and agriculture-dependent for food, man built structures made from materials found within his turf. In areas where timber was plenty, wooden dwellings developed, mud bricks were likewise used where materials was rare. The Mesopotamians (c. 2000-700 B. C. ) were the first known civilization to use bricks in their dwellings. Brick made during this period was a mixture of clay or mud and straws (added for strength) and then sun-dried or kiln dried; a product that is purely endemic to the region, owing to the scarcity of stones, timber and other building materials (Fletcher, B.
1961, p. 50). The Egyptians likewise had their share in the use of bricks as a suitable building material; as new advances were made in curing, texture, color and drying techniques. Different types of bricks were used to adorn structures, from Temples to Mastabas or even simple abodes (Fletcher, B. 1961, p. 13). Hebrew slaves were hired, cruelly dealt and oppressed so production of bricks and construction of monumental buildings could be achieved. In the end, the domination of the Egyptians culminated with the Hebrews departure to the Promised Land (Christian Community Bible, 1997, p.
85). The later part of the 17th and the entire 18th century bricks were utilized as lining for timber framed residences, to serve as insulation against the cold weather, which was later called brick nogging (Friedman, D. 2006). Bricks were fitted in the cavities between the vertical and horizontal studs; mortar was applied as adhesive and finished off with plaster. Thus today, old buildings can be easily identified through its brick nogging on the wall and the year it was constructed could probably be determined (Friedman, D. 2006).
Brick as a building material played a key-role in the development of Architecture and the building industry for a span of over 2,000 years. Frank Lloyd Wright (1867-1959), the famous American Architect, found full artistic expression in natural materials—bricks included and exploited its potential by using it not only on residences but also on high-rise buildings. He is credited for the saying “in their hands the ordinary brick became worth its weight in gold”. Important landmarks in cities and urban centers are clad with bricks; some were imported if not available locally (Larkin Building, n.
d. ). At the start of the 20th century modern architecture, the popularity of bricks waned. In its place, concrete and steel became the material of choice because of the demand for bigger and taller structures. Brick does not have the structural capabilities for these structures; besides, modernist’s (Architects) opted for simpler designs and faster construction application. So, buildings of concrete, steel and glass replaced brick structures (Beardmore, R. 2006). Overview on Brick Wall Cladding Systems
Brick or hardened clay is literally dull, uninteresting and devoid of radiant color, yet when placed to adorn buildings, residences or even lobby’s, it exudes an aura of sophistication, strength, stability and grandeur not evident in any other building material. Apart from stone, brick is probably the oldest and its resurgence as a choice material has baffled Architects since no comparable material comes close to its character, apart from being cost effective, durable and eco friendly (Wikipedia contributors, 2007a). On timber frames
Brick-cladding on timber frames has been with us since the start of the 20th century and continues to be popular in the construction industry. That is why series of innovations have proliferated particularly in the installation process. Normally bricks are laid out on a stable masonry foundation and piled one over the other with mortar and joint pointing is done using the proprietary pumped system (Self Build Houses, n. d. ). At every strategic horizontal layer of brick, metal ties are integrated to keep the piles in place and normally these are anchored to timber studs.
The metal ties hold the brick walls from collapsing over, especially during extreme thermal changes, extreme wind pressure or during earthquakes (Parker, H. 1968b, p. 28). On concrete walls Brick-cladding on concrete or masonry walls is performed simultaneously with the block piling, or can be installed separately on existing walls. Bricks are piled together hand in hand with the concrete blocks and share the same foundation bed but is separated by an air gap that is totally independent of each other. It is like building two walls at the same time, one of concrete blocks the other made of bricks.
At every 3rd layer of concrete block, steel ties are laid out connecting both the vertical reinforcement (concrete and brick) at widths not exceeding 600 mm, this should give structural stability to the installation (Baggeridge Brick Plc, 2003). In cases where walls are constructed prior to the installation of bricks, dowel provisions are made at wall points not exceeding 600 mm on center, both vertically and horizontally. Metal ties connected to the bricks vertical reinforcement are then welded to the wall dowels (Parker, H. 1968a, p. 91).
If dowels are not provided, workers will drill-in anchor bolt to strengthen the installation. All metal ties are provided with slot for thermal movement because bricks expand over time while concrete does the contrary, shrinks (Parker, H 1968a, p. 256). New brick installation system In terms of brick installation, some methods have been developed to reduce construction cost and speed-up completion time. One system uses a galvanized steel backing plate that holds a specially designed brick (Baggeridge Brick Plc, 2003); another type employs inter-locking brick panels and eliminates the use of mortars (Self Build Houses, n. d.
); there are still others who have designed options to promote ease in the installation system. This new trends in brick application, though practical and cheaper, have been used only in the mass housing business, because these types are not designed to endure strong quakes and will most likely collapse (Dunn, V. 2001). For most residents, if they can spare the cost, would still prefer the real thing—that is to install bricks the conventional way. This sentiment, as shared by many, drives up the resale values of real estate because buildings made the conventional way project an image of durability and a lasting antique appeal.
New building technology The use of SIP’s, or the Structural Insulation Panel was developed as outer wall envelopes on timber-framed structures. It is actually a wall system combining an Oriented Strand Board (OSB) with an insulation panel. It speeds-up construction time, reduces timber framings and improves the energy performance of buildings (Wikipedia Contributors, 2007c). The ICF System or the Insulated Concrete Form Wall Construction is the counterpart of the SIP, but solely developed for concrete buildings.
It utilizes lightweight blocks made from either Expanded Polystyrene (EPS) or Extruded Polystyrene (XPS) with a core 4, 6, 8 or 12 inches depending on the structural requirement. The blocks are arranged around the perimeter of the building, structural bars are installed and concrete is pumped into the core, giving a continuous wall of concrete and insulation. Much like the SIP panels, ICF improves the insulation coefficient of buildings (Toolbase Services, 2006). Energy performance Bricks when subjected to direct sunlight absorb a lot of heat which normally takes 3 to 5 hours to dissipate.
Thus, when not properly insulated, it affects the inside temperature of buildings or residences, thereby putting a lot of strain on the air-conditioning system to raise energy cost. This condition is most likely during the summer months but is preferred during the winter season because it helps stabilize room temperature up to about 8 or 9 in the evening (Claybricks & Tiles Sdn. Bhd. 2006). Bricks, the symbol of traditional culture, serve its purpose only as a decorative material. SIP panels on timber-framed structures reduce heat transfer coefficients both during winter and summer time.
SIP panels stabilize humidity and room temperatures. It is likewise the most energy efficient wall cladding devised for timber structures. This system of construction reduces timber dependence and helps our ecosystem (Wikipedia Contributors, 2007c). For the insulated concrete form (ICF) wall construction, conduction of heat between the brick and concrete panel is reduced since EPS or XPS insulating material envelopes the wall, both inside and outside, freeing buildings from the usual problems of energy efficiency.
The thickness of the EPS or XPS barrier is usually 2 inches, while that of concrete varies from 4 inches to as much as much as 12 inches. If structural considerations suggest that thickness be over standard sizes, then special panels are manufactured (Amvic Inc, 2003). Normal brick cladding systems can be applied over the panels or for added protection, moisture barriers are installed before bricks are laid directly on the EPS and XPS panels (McMichael, C. 2006). Construction Efficiency
Construction speed and efficiency in brick cladding is best observed in timber-framed buildings because the system of attachment is easier, thereby work schedule is accurately met (Self Build Houses, n. d. ). Before bricks are laid, an asphalt based felt-paper or vinyl-based building wrap is stapled to the wood studs on the perimeter of the building as moisture insulation and metal ties are simply anchored to hold the structure (brick wall). The same method is used for plastic shielded galvanized steel backing because it can be screwed on timber studs, so construction time is swifter (WIE, 2004).
The contrary is observed in concrete construction. The system proves to be more complex and time consuming. Construction of concrete wall and brick cladding is started simultaneously with an air space between the panels; besides metal ties are harder to install to further delay construction time. On previously finished concrete walls, the installation is quite similar but metal ties are either welded or provided with anchor bolts. It is observed that construction costs are much higher in concrete structures compared to either timber or steel (REU, n. d. ).
Brick cladding in concrete walls should be confined to manageable areas since both materials behave in opposite ways. As wall installation ages, brick walls tend to expand while concrete walls contract. For a thirty meters brick wall, total expansion is found to be at the rate of 11. 4 millimeters. Thus, when walls are not provided with expansion joints it buckles and no amount of metal fastener can hold it in place (REU, n. d. ). The brick wall will most likely crack or collapse if the moorings are abruptly released or the concrete wall where it is attached may suffer considerable damage (Dunn, V.
2001). Every installation should be carefully studied and expansion and contraction joints thoroughly spaced so untoward damage can be prevented. Brick installations over two floors in height are now provided with slip joints to give them (brick clad walls) freedom of horizontal movement during earthquakes. Acoustic Absorption Brick as a material is porous so expect sound to pass through, it cannot be used to shield confined spaces from outside sounds, nor is it effective in containing inside sounds so that it becomes inaudible from the outside.
But when bricks are used in the interiors, it helps control echo, reverberation and standing sound. In short, bricks improve the acoustic rating of a particular room (Acoustics, n. d. ). Brick clad timber framed structures have very poor sound containment coefficients, particularly in containing sounds coming from the outside. While concrete structures with brick cladding somehow fare well since sound transmission is muffled as it crosses through the panels (concrete), it remains a poor sound absorbing material so walls have to be treated with acoustic materials (Acoustics, n.
d. ). Bricks are classified according to its degree of porosity, it could be a common brick, a compressed brick or perhaps a firebrick. Each type is designed to serve different requirements. Brick panels installed inside living areas or conference rooms not only enhance aesthetic appeal but also improve acoustic resonance. Brick walls absorb sound—whether standing sounds and reverberating sounds and to a degree correct echo and flutter echoes (Encyclopedia Britannica, 2007). Since bricks transmit sound readily, additional barriers should be introduced to contain sound.
If a brick wall is made as partition between rooms, privacy will be totally lost, since others would be privy to conversation made on the other side of the room. Not so much with concrete walls, since concrete walls are naturally dense and when properly plastered is massive enough to mute sound transmission. However, it does not have the absorption quality of bricks, so its acoustic resonance is practically nil (Encyclopedia Britannica, 2007). The introduction of heavy drapes, carpeting and cushions could easily be a good remedy. Durability Without a doubt, brick is the most enduring of all man-made building materials.
The specific proof of this are the Mastaba (burial mound) of the Egyptian’s that was built over two thousand years ago, recently unearthed, but the brickwork inside are still in excellent condition (Fletcher, B. 1961, p. 23). In fact brick walls can withstand harsh weather conditions, could be soaked in salt water indefinitely and above all the most potent of man-made chemicals do not seem to have an effect on it. Architecturally, the aesthetic appeal of bricks is enhanced over time as it ages, probably the same as wine since its taste also improves as it matures (WIE, 2004).
The abject durability of a monolithic poured reinforced concrete could not be discounted. Proofs to these are the embankments made during the 2nd World War that continue to exist even without maintenance. In fact plain concrete is a product of the 20th century, although the main material cement was actually invented by the ancient Roman Civilization. Cement during the Roman period was made out of volcanic ash mixed with lime and other substances and was used extensively for their buildings (forums, thermae, collosseums, circus, aqueducts and temples) that house different activities (Fletcher, B. 1961, p. 210).