Low Rise Construction

P1: Low rise construction

In this report I will introduce forms of low rise construction and show how a combination of traditional and modern techniques are used in today’s construction industry. I will also discuss the materials used for different methods, the limitations of structures and materials and some environmental factors around building techniques.

Forms of low rise construction

Low-rise construction refers to buildings that do not exceed three storeys in height. A domestic building refers to a place of dwelling or residence. A commercial building refers to a place that makes or is intending to make profit. Examples of domestic and commercial buildings currently used are:

A detached house is a standalone property that shares no walls with any other building. This type of property has a tendency to have additional features such as a garage with a potential driveway, land to the front rear and possibly sides as well as outer buildings or room for expansion. The location of such property has varied over time as development has increased. More remote and secluded areas became more desirable resulting in urban sprawl.

A semi-detached house is one building divided into to two separate living spaces with a single partitioning wall. This type of property has living spaces that are likely to have a mirror image layout of one another. They are also likely to have a reasonable amount of land and an off street parking space. They tend to be located in suburban areas on an avenue or cul-de-sac.

Terraced housing is a row of generally identical linked residences that share side walls. This type of property tends to have little land and smaller and fewer rooms. Often situated in the CBD (central business district) and in built up medium density areas and generally offering on street parking.

Differences in building methods

Traditional building is often used to describe buildings where majority of the construction occurs on site. Solid structures of traditional methods have internal load bearing and external non-load bearing walling of masonry construction. Load bearing means that it bears the weight of the structure, for example a house, and conducts this weight to the foundation structure. The outer non-load bearing wall provides security, protection from element and aesthetics. The two walls are held together with ties and the space between the walls is called the cavity which is filled with insulation.

Masonry construction using brick and blocks offers a lower utility cost for homes and buildings due to the energy efficient qualities which allow for a warmer home in the winter and cooler in the summer reducing the nation’s energy needs, and providing a cleaner environment. The materials are also very durable and don’t need a lot of maintenance such as coatings for protection like a timber frame. However, there are limitations including the costly repair bill as damage to a particular part requires the removal of the whole section. Also poorly made bricks are more prone to chipping and wear. Porous bricks are susceptible to mould and freeze thaw in different climates.

Prefabricated construction is a more efficient form of sub-assembling majority of the structure in workshops and taking them to the site to be assembled.  This method significantly reduces the on-site construction time and many health and safety risks are reduced or eliminated when most of the work is carried out in a safer workshop environment.  Less time on site means less pollution and impact on the surrounding community by noise, light, and air pollution. On the other hand, prefabrication leaves little room for design change when the project is underway. Prefabricated homes can be expensive to transport and if the site becomes difficult this can add excessive amounts to the budget and counteract the efficiency advantages.

Building Structures

Different types of buildings require particular structures to achieve optimal purpose. Domestic buildings such as houses, hotels and care homes tend to have solid structures whereas commercial buildings vary as they use both solid structures and frames.

Timber frames are a popular choice for housing as wood is: a light material that allows for easy and quick construction; a widely available renewable material and is easily adapted. Timber is a common material to use due to its strength. It is stiff and quite strong and in comparison to steel is light, pliable and anisotropic, meaning it has a high compressive resistance. However, there are limitations when using a timbre frame. Wood is subject to processes of decay (rotting) as it was once a living thing. Its combustible nature means it burns quickly and easily beyond repair so protective layers must be applied to marginally change the way it burns to slow the process. Also wood is high maintenance as it is susceptible to attack by mites, fungi and spores and so requires coats of paint and preservatives such as creosote.

Steel frames are used in low rise construction for industrial units and warehouse like structures. Steel is an immensely strong material and has some flexibility and is ductile. This means when a force is exerted on it, it will bend out of shape slowly rather than cracking like concrete or breaking like wood allowing it to perform well in earthquakes. The frames are quickly constructed at site as a lot of the work can be done at the workshop. However, steel loses its strength at high temperatures so needs to be protected with boards or spray on fire protection. Also it is susceptible to corrosion in humid environments.

Reinforced cement concrete (RCC) frames are made of concrete containing steel bars. Concrete is strong in compression and inexpensive whereas steel is very strong in tension making it a good combination of materials. Concrete frames can be cladded with any cladding material allowing for aesthetically pleasing exteriors. Concrete is a very durable and versatile material and has limitless architectural possibilities. However without reinforcement the materials lack of tensile strength means it does not perform well against earthquakes and strong forces. It also occupies a greater area than steel or timber as the beams and columns are larger. Concrete is also non-renewable as it uses raw materials.

Types of roofs

When referring to roofs the term ‘pitched’ refers to the gradient/ measure of steepness. Flat roofs are about level with the floors and are generally used in dryer climates where the roof can be utilised as a functional space. These are cheaper as they don’t use lots of material for a structure. The roof span is the distance across a roof between the seats of the opposite rafters.

In modern construction trussed rafters are used that are prefabricated in workshops. These are triangular frames that support the roof fabric. Gabled roofs have a portion of wall that extends up in a triangular shape between two pitches. A mono pitch roof has a single pitch in one diagonal direction with a gable end. A hipped roof has all sides of the roof sloping down in the direction of the walls and has no vertical sides within the roof structure.

References

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Archiexpo.com. (2016). Ancon Building Products: Building & Construction - ArchiExpo. [online] Available at: http://www.archiexpo.com/prod/ancon-building-products-69643.html [Accessed 22 Sep. 2016].

Thisisbuildingmaterials.blogspot.co.uk. (2012). pros and cons of brick and block. [online] Available at: http://thisisbuildingmaterials.blogspot.co.uk/2012/03/pros-and-cons-of-brick-and-block.html  [Accessed 22 Sep. 2016].

'RightmoveOverseas.co.uk'. (2016). Check out this overseas property on Rightmove!. [online] Available at: http://www.rightmove.co.uk/overseas-property/property-47956342.html  [Accessed 26 Sep. 2016].