ROOF TYPE

Composition (asphalt shingles)

· ranges from low-cost 3-tab shingle to architectural shingles with extra durability and style
· many colors, types, and manufacturers
· fire resistant
· scars easily when hot
· environmentally unfriendly
· composition roofing material absorbs and holds more heat than wood shake or shingles.
· The asphalt base of composition roofing absorbs the sun's rays and radiates heat for a longer period of time than wood.
· Lighter-colored composition roofs absorb less heat than darker-colored ones.

Wood,shingles or shake

· natural look weathering to a soft grey
· offers some insulation value
· blends in with the environment
· easy to repair or replace
· long lasting if maintained (30–50 years)
· usually requires professional installation high maintenance
· tends to rot, split, mold, and mildew
· poor fire rating unless presure treated
· Wood does not conduct heat.
· Wood shakes are also individual pieces that allow air to circulate.


Metal (steel, aluminum, tin, copper)
· available in different looks including cedar shingles, slate, or standing seam
· may be difficult to install
· can be expensive
· may need periodic painting
· have inherent properties that cause roofs constructed with these materials to become exceptionally hotter than other roofs.
· absorb most of the energy reaching them from the sun (high thermal absorption), reflect little energy (low reflectivity), and conduct heat very rapidly (high thermal conductivity).
· Therefore, there are special design considerations for underlayments used under these metal roofs, due to the high in-service temperatures that these roof assemblies can reach.



Tile (concrete, clay)
· many colors and styles
· attractive
· fireproof
· easy to maintain
· extremely durable when maintained
· fragile; walking on roof may break tiles

Slate
· beautiful, distinctive appearance
· fireproof
· long life span
· low maintenance
· heavy
· fragile

ACID AND BASES

Acids taste sour, are corrosive to metals, change litmus (a dye extracted from lichens) red, and become less acidic when mixed with bases.
Bases feel slippery, change litmus blue, and become less basic when mixed with acids.

AIR

air is the most important thing for life things in this world because in air are contains oxygen, hydrogen and many more gases..Air is a mixture of variety of gases, air is the life sustaining substence for animal and human water vapour and small amounts of other elements , Higher in the atmosphere. People can only clearly notice the prescence of air when the wind blows.The air we breathe consists mostly of the following gases:

Nitrogen (N2)78%

Oxygen (O2)20%

Noble gasses1%

Carbon dioxide (CO2)0,03%

Water vapor (H2O)0,97%

Brick, Roof and Tile
Heat is one of energy that we cant create, cannot be destroy but can transfer from one matter to the other matter which is solid, water even gases. In our life, heat is very important for example, heat is using for cooking, decayed process and combustion process. But too much heat will be a problem to our life. For example, in construction to build a house, we have to prevent the heat so that we can have a comfort house to live in. in order to do that we have to use a batter roof to prevent the heat from enter the house. Brick, roof and tile is use to decreasing the temperature in the house. Bricks are divided by their formation and their composition such as common brick, face brick, clinker brick, press brick and many more. Common brick is use generally to build a buildings because its hard and more durable kinds are preferred for this purpose.