eBusiness Weekly
Engineering and Construction Matters
With Innocent Chatikobo
Introduction
A floor is a horizontal and structural element of a building. There are two types of floors
a) Solid ground floors: their base is on the ground and they provide support for occupants and their belongings such as furniture and equipment
b) Suspended floors: they are supported by reinforced concrete foundation columns. They carry both the dead and live loads of the building. These are normally found on multistory buildings and on special foundations
Floor construction process
Generally, floor construction can be divided into two construction processes namely separate and monolithic construction
a) Separate construction method: in this method the floor substructure and the floor finishes are done in two distinct stages. The concrete slab is cast and left rough to ensure bonding with floor finish. The slab is cured then at a later date the topping is laid separately. Usually the walls, roof, plaster and sometimes painting are done before floor finishes are laid.
The concrete slab is cleaned in preparation for the finish. Cleaning is done to remove old mortar droppings. Then a cement and river sand screed is applied and then the desired finish is applied. The advantages of this method are: its easy to lay and maintain; different colours can be applied using oxides
b) Monolithic construction method: both the floor substructure and the topping are laid in one operation. This method has an advantage of segments setting at the same time and this reduces the chances of severe cracking. Sand-cement screed is applied on top of the concrete and floated on the same day of casting of concrete slab.
On the floated screed, sprinkle cement powder and steel float to finish it. To obtain a required colour, we can add oxides. Instead of sprinkling cement powder, we can use cement slurry and steel float to obtain a smooth surface. After laying the finish, the surface should be cured for several days (at least 3 days)
Factors determining type of floor finish
A variety of finishes is available for selection. The following are some of the considerations taken into account before one finally decides on what to choose
Type of building
Intended function of the building
Type of materials available
The costs associated
Number of people to occupy the room at any given time
The location of the building
Ease of cleaning and maintenance
Anti-slip properties (traction)
Thermal and sound insulation needs
Appearance
Resistance to moisture e.g. in kitchen and bathroom
Durability — designed lifespan of the finish
Resistance to wear and tear
Types of floor finishes
During or after casting the floor slab, many types of floor finishes can be applied. Some of the floor finishes are as follows
a) Granolithic: the term grano describes a mixture of cement and aggregate and adequate water. This type of finish is generally given a smooth finish by using a steel float.
This finish is preferred because its one of the cheapest finishes and is an all -purpose finish. However, its disadvantage is that it is considered as a dull finish and is also generally cold
b) Terrazzo: this comes from a mixture of marble chips and a cement base from white cement. This finish is suitable for high traffic and water prone areas such as receptions, garages, bathrooms and toilets. This finish is very attractive because it can be polished to give a smooth surface. It is very hard and wear resistant; easy to clean; and water resistant. Its main challenge is the high initial cost which is prohibitive
c) Vinyl: The Polyvinyl Chloride (PVC) is available in different colours and sizes e.g. in sheet ant tile form. Some of the designs for the sheets and tiles are imitation of wood and marble and they can produce a pattern depending on tile design.
They are laid using an adhesive on top of a wood float finished screed. This finish is usually used in bathrooms and kitchens. It is a very durable and resistant floor finish capable of withstanding grease staining, moisture penetration, abrasion, alkaline and acid damage. It is easy to clean.
d) Wood block or wood parquet: comprises small shaped timber pieces from either hardwood or softwood, though hardwood is preferred due to its durability. The timber pieces are polished to give a shiny surface and can also be laminated for resistance to grease or water.
This floor can be laid directly on a screeded floor using a suitable contact adhesive or can also be laid on a mastic base. This finish is used in dry areas of the home such as the living rooms and passages. Some of its advantages are: wood is very durable and has a rich natural beauty. The floors are warm and easy to clean. Its disadvantages are that it is more expensive than most floor finishes and usually separates from the base when exposed to moisture
e) Carpeted surfaces: carpets are available ranging from synthetic fibres to wool or a mixture of the two.
They are also in different measurements.
Carpets can be laid directly on a grano finish, wooden blocks, or wood floated screed. They can be laid wall-to-wall (covering the whole room) and nailed around the perimeter or an edge strip can be used.
Carpets are suitable for use in dry areas such as living rooms, offices, auditoriums, and also lecture theatres — for acoustic reasons.
Their advantages are that they give comfort, luxury and warmth. They also have an attractive appearance and if well selected, their colour and texture may be used to match existing furniture
f) Quarry tiles: these are hard floor tiles found in different colours. The finish can be made from slate, sandstone, quartz, limestone, granite and marble. They are laid using a floor adhesive or mortar on a screeded surface.
They are commonly used in rooms in which water is used e.g. bathrooms, outside paving, etc. they are decorative and can be used in reception areas and staircases. Their disadvantages are that the floor is cold, hard and produces noise when walking on it
g) Rubber finish: the material is usually found in plain colours and in sheet form. The laying is similar to that of PVC sheets. This is ideal for bathrooms and kitchens. It is easy to clean and have excellent anti-slip properties. The disadvantage is that it gives a cold surface.
h) Clay tiles: these can be available as ceramic or porcelain tiles. The sizes of the tiles vary and their designs also vary. They are laid on a wood float finished surface using the appropriate adhesive and the space between the tiles is filled using tile grout.
They can be used in both dry and wet areas such as sitting rooms, public auditoriums, bathrooms, kitchens etc. they are very decorative and easy to clean. Their disadvantages are the cost factor; highly fragile and the surface is very cold
Innocent Chatikobo is an Engineer by profession with AtroServe Engineering Zimbabwe. He has extensive knowledge and experience in Structural Engineering and Construction. For your comments, views, questions and feedback he can be contacted on the following platforms; Cell: +263 777 950 224; +263 712 376 037; +263 782 502 732 .Email: [email protected] .Facebook: AtroServe Engineering Zimbabwe
