Unit Overview
P6 Performance Criteria
P7 Production and Manufacture
P8 Important Features
P9 Material Deterioration
P10 Prevention of Deterioration

P6 Identify The Main Performance Criteria of Construction Materials

The properties required by materials for construction include the following:

  1. Strength
  2. Aesthetics
  3. Weather or waterproof
  4. Durability
  5. Cost
  6. Thermal Resistance
  7. Sound resistant
  8. Fire Resistant
  9. Weight
  10. Environmental Impact

 

Concrete
Materials that will be loaded directly from above must have good compressive ability, concrete is very good for handling high compressive loads, it is good when used in walls and foundations.  Concrete’s PSI can be improved by reducing the water content or increasing the cement ratio so it can withstand higher compressive loads, however this makes it harder to flow and form into more complex shapes.

 

 

Concrete is a dense heavy material and therefore is very good at sound proofing, it is normally selected for floors in apartment blocks over timber floors. Concrete also has better fire resistant qualities. Concrete has a high embodied energy which means it uses a lot of energy to produce it.

 

Complex shapes including curves can be created by concrete and steel rebar is normally added to improve the tensile strength (ability to withstand flex)

 

Timber
In domestic buildings timber such as pine is adequate for beams, joists and rafters, it can withstand a flex or bending force, this is often found in the form of three point loading which is common on suspended floors. Softwoods are relatively cheap and easy to shape. Pine is the main supporting material in timber frame housing, it supports the load of the building.

 

Eco joists and engineered timber can be used when heavier loads will be encountered or longer spans are needed.

Timber is used internally for doors, frames, window cills and skirting boards, there are a variety of woods that can be used for flooring.

 

Softwoods such as pine are cheaper and lighter than hardwoods such as oak, however hardwoods are normally longer lasting and harder wearing. Cedar can be used for cladding and shingles as it is naturally water repellent.

As wood can be replanted it is a renewable source, consideration should be given to the location the timber comes from and the effect on the environment of transportation.

 

 

 

 

 

 

 

Glass
Glas is important in construction as it allows natural daylight into a building, it is generally not strong in terms of supporting the building, the walls above need to be supported with lintels. In some commercial buildings the glass does have structurally ability. Glass is often used as a casement in windows with a xenon gas to help lower the u value and prevent heat loss.

 

Steel
Steel is essential in wide buildings such as supermarkets and buildings above 5 stories in height, by using steel in concrete it is given tensile strength to resist cracking and shear when flexed. I beams and rolled steel joists (RSJ) can be used to form the frame of a building.

 

Steel is expensive to produce and hard to shape, it also requires a high skill level to build with it. As a material it is not very environmentally friendly, although it can be recycled.Steel can rust and deteriorate if not painted or treated in any way.

 

Insulation
There are a variety of insulations available that vary on cost performance and environmental impact. Natural materials such as sheeps wool have a very low impact on the environment, but are limited in their performance and use. Foams such as celotex can be used in compression under screed and have a very good u values. When used in SIP’s buildings foam is glued between two sheets of OSB and forms part of the buildings structural integrity.

 

Bricks
Bricks range in colour from yellow and red to dark blue, they can be used to support the load of a building when used in cavity wall construction or for cladding on concrete and timber buildings. Engineering bricks are heated for longer and to higher temperatures and can therefore withstand heavier loads and be used underground in direct contact with moisture present in soil.

 

Historically bricks have varied in colour depending on the region they have come from as have the styles of brick work such as flemish and old English bond, a local planning authority may insist on a certain type of brick to fit in with the appearance of the other buildings in the area.

 

Plaster
Plaster is used to provide a smooth internal finish and is normally applied to plaster board. Extra layers of plasterboard can be added to improve fire resistance and sound proofing.