A floor finish is a liquid that is applied to a resilient tile floor and dries to a hard, durable and smooth film. The selection of the appropriate finish is an essential part of floor design which can have an impact on the performance and overall economics of the floor. The finish should be appropriate to the service conditions for which the floor is required, with particular reference to the type of traffic and loading, impact, abrasion, chemical resistance etc.
High quality floor finishes may contain as many as twenty-five ingredients. Some of these ingredients evaporate while others remain on the floor after drying. The ingredients that evaporate are called, “volatile” components and the ingredients that stay on the floor are called, “non-volatile” components. The volatile ingredients assist in the film formation, drying and curing of the finish and then evaporate. The non-volatile ingredients are the solid materials which stay on the floor and make up the floor finish film. The ingredients used to make floor finishes combine to produce a balanced blend of physical and performance characteristics. Some of these characteristics include: hardness, gloss, clarity, scuff resistance, slip resistance, water and detergent resistance, removability, recoatability, and toughness.
Factors affecting the selection of Industrial floor finish
Several factors are affecting the selection process for floor finish, given below is the analysis of each point.
Abrasion resistance – Abrasion resistance is the ability of a surface to stand up to wear and tear caused by foot and mechanical traffic and mechanical equipment. Given time, all floors will experience wear – scuffing, scratching and rubbing away from the surface. Some surfaces hold up better against abrasion than others. There are tests to ensure your floor will meet abrasion-resistance standards.
Impact – Where the impact is severe, cement rich concrete using natural aggregates tends to be brittle, and the use of natural aggregates, or steel-fibre, may be suitable. Resin-based toppings may also be considered. Recommendations for their use should be obtained from firms who specialize in their manufacture and application.
Chemical resistance – The chemical attack can destroy floors, walls, and linings quickly. Chemical-resistant flooring, wall, and lining systems contain properties that protect these areas from spills, splashes from acids, alkalis, solvents and other corrosive elements.The quick destruction of floors, walls, and linings due to chemical attack cost companies time and money. Protection for their harsh environments is crucial to their success.
Dusting – Powdering at the surface of a concrete slab is called dusting. It is characterised by a light-powdery surface that may weather to expose the aggregate. Dusting surfaces powder under any kind of traffic and can be easily scratched with a nail or even by sweeping. Dusting can be rectified by the application of a chemical floor hardener or, in severe cases, wet-grinding the surface and laying a bonded proprietary screed. Alternatively, the surface can be covered with an overlay of flooring
Slipperiness – Slippery floors may be caused by over-troweling to produce a very smooth surface or by the use of some types of aggregate, particularly limestone fines. Sliperness may equally be caused by neglect of elementary cleaning procedures, or by the use of some types of floor finish.
Decoration – Where a decorative floor is required, this may be achieved by the use of coloured pigments and selected coloured aggregates which are revealed by grinding and polishing the surface, or by coloured penetrating resins, paints or special coatings.
Industrial Flooring Finishing techniques
The prerequisite for a good performance from a concrete floor surface is full compaction and this is usually fulfilled using a single or a double beam compactor that is fitted with a vibration unit. The action of surface vibration tends to draw water to the surface and wet finishing may produce a weak layer at the top. If this is not removed, the hardened surface will have low durability and wear resistance and a high risk of dusting. The following techniques may be used with most of the construction methods[ which will be discussed in an upcoming article].
Traditionally floors are finished by successive trowelling with steel trowels, with a delay of an hour or more between each travelling to allow further moisture to evaporate.Surplus weak mortar should be scrapped from the surface as trowelling proceeds and by exerting considerable physical pressure on the trowels during subsequent travelling to close the pores in the surface left by the evaporated moisture, a skilled man can produce an excellent floor.
A power float can be used as a preliminary to power trowelling to regulate and close their surface. Power floating eliminates the time and materials needed to apply a finishing screed and is quicker and less labour-intensive process than hand trowelling. Power floats have an electric motor or petrol engine fixed over a circular pan or skimmer which smooths concrete before hardened steel reversible metal blades rotate at up to 150 rpm over the surface to create a hardened finish.Floating usually starts at one end of the slab and moves to the other. The operator holds the float at waist-height and moves backwards so that the float removes their footprints. The speed should be slow and consistent.
No mortar is removed during power trowelling and timing is therefore critical if a hard-wearing surface is to be achieved. Surface moisture must evaporate particles not to be torn from the surface. The precise timing depends upon mix proportions and ambient conditions, but timing is far less critical than for power trowelling and overtime working is unnecessary. Grinding at later stages becomes progressively slower and less economic. The technique should produce an over-all ‘glass paper’ texture without excessive exposure of coarse aggregate and give good wear and slip resistance.
Hard floating and brushing
Where a high- grade surface is not required and traffic is light, the initial finishing with the skip float may be adequate or a brushed texture may be applied with a bristle broom to give improved solid resistance. Alternatively the surface may be finished with a hand wood float which will leave a slightly coarse texture. A floor with this finish may not be easily cleaned.
The accuracy of setting side forms probably has the greatest influence upon general surface regularity and in particular steps or lips at joints should be avoided. The use of long-strip construction methods is an aid to better surface regularity by the elimination of many wet-formed joints. Discussed in detail are the factors affecting selection of industrial flooring finish and techniques being practised.