Blocks vs Bricks Q5

Q.
a) Apart from bricks, blocks are also used in the construction of walls. Explain what is a block and describe the types of blocks that are commonly used. (15 marks)

b) Explain the advantages and disadvantages of blockwork compared to brickwork. (10 marks)

(25 marks, 2013 Q5)

A.
a) Earlier post Past year 2012 Q5b Various types of bricks is referred.

Blocks

A good write up is about Bricks vs Blocks here.

Both concrete block and brick masonry are strong, fire-resistant, insect-proof building materials. They have a lot of thermal mass, which helps them retain heat and makes up for their relatively low insulation value. However, despite their similarities, block and brick have some major differences. If you're thinking about building a new home or adding on to an existing one, learning the differences between brick and concrete block can help you make an informed decision.

Insulation Value

According to Inspectapedia, basic brick walls have an insulation value, or R-value, of 0.2 per square inch. By comparison, plywood has an R-value of 2.5. Many “brick” homes are actually wood-framed homes with brick sheathing, and have insulation values comparable to other wood-framed buildings. Conventional 8 inch concrete block walls have an R-value of 0.08 per square inch, or about 2.5 for the whole block. Insulated concrete blocks can increase their R-value to about 1.2 per square inch, and air-entrained blocks can have R-values as high as 3.9.

Strength

Brick and block are both relatively strong materials, but their strength in a wall is affected by the type and quality of mortar holding them together. According to the Masonry Advisory Council, all concrete blocks must have a minimum compressive strength of 1900 pounds per square inch. Many dense blocks are stronger than this. According to Mechanical Properties of Unreinforced Brick Masonry, the average concrete block can withstand 3500 psi, while the average clay brick can withstand 3000 psi. High-cement mortars can withstand up to 2500 psi, while mortars high in lime are weaker, and may be able to stand only about 350 psi.

Cost

Both bricks and concrete masonry are relatively inexpensive. As of 2011, a single clay brick costs about $1.50, while an 8 inch concrete block costs about $1.35. Special lightweight blocks can cost as much as $3.00 each. Labor can bring wall prices up significantly, however. According to the MAC, a single large lightweight concrete block can cost around $11.00 installed, while a heavier block costs as much as $15.00. Traditional brick masonry requires more skill than concrete masonry, and may be difficult to do on your own.

Weight

Concrete block and brick are both quite heavy materials. Their individual weight depends on the materials and type of construction, however. The average clay brick weighs around 5 pounds. Conventional 8-inch concrete blocks weigh around 43 pounds each. Autoclaved aerated concrete, or lightweight block, can contain as much as 80 percent air, and weigh as little as 20 percent as much as the same size conventional block.

Ref:
G.D. Palmer, eHow Contributor. Concrete Block vs Brick, available at
http://www.ehow.com/info_7943641_concrete-block-vs-brick.html

b)
Pros and Cons of brick and block

Advantages of Brick:

• It can withstand heat thus giving fire protection to the house or buildings
• It has better sound performance where it able to block the sound from outside.
• It also offers lower utility cost. Energy efficient homes its inherent mass qualities help keep a home cooler in the summer and warmer in the winter.
• It reduces the nation’s energy needs and produce a cleaner environment
• It offers wide range of non-fade colors.
• It does not require painting for protection from being destroyed like woods.
• It is a load bearing material which is it also help to support the building.
• It is virtually maintenance-free. It never needs painting, caulking or staining.
• It won't burn or rot like other finish materials

Advantages of Block: