Everything you need to know about the products to use after a flooring installation – products that are beautiful and effective.
Is there anything more exhilarating than stepping back and appreciating the splendour of a final floor that has come together beautifully? That greatly satisfying moment will of course have been preceded by the careful selecting and installing of numerous products that incorporate innovative features and technological advancements while making use of professional and reputable services. The so-called ‘magic ingredient’ that rounds off the “rough edges” and leaves behind a successful and lasting flooring installation all boils down to the type of final flooring solution selected.
For this reason, take note: In this feature we identify all the types of final flooring solutions available and briefly explore why these are used, how these should be installed and what fine details often result in a breathtaking flooring installation.
Screeds are usually composed of a cementitious material made from a 1:3 or 1:4.5 ratio of cement to sharp sand. A screed may be applied onto either a solid in situ concrete ground floor slab or a precast floor unit. When it comes to application, the screed may be directly bonded to the base, with a minimum thickness of 25mm, or laid unbonded onto a suitable damp-proof membrane which is placed over the slab, with a minimum thickness of 50mm. Should the floor contain underfloor heating pipes, a screed with a minimum thickness of 65mm needs to be laid.
Alternatively, the screed can be applied as a floating finish over a layer of rigid insulation material where it should be a minimum of 65mm thick, or 75mm in the presence of underfloor heating pipes. The screed may be left as finished, or floated to produce a smooth surface on which to lay the specified flooring or finish. Screeds can also be used to enclose underfloor heating pipes or as a path to route services.
Since the use of a screed is key to good-quality solid flooring, it is not advisable to apply the floor finish directly to the structure. A screed is used to create a smooth, level surface, or even as a path to route services. Three basic criteria drive a good screed design: strength; bonding; and moisture control. These will be discussed along with other critical factors that can be implemented.
• Structural floor base
Concrete is the most common base. The designer must establish the surface characteristics of the slab and the nominal thickness being allowed for the screed early in the design process. The thickness will have a large influence on the make-up and method of laying, as well as the nature of the bond.
• Quality Control Standards
Most screeds can achieve a high-quality finish with less than 3mm deviation over any 3m. The floor finishing material defines the quality needed. For ceramics or stone using thin-bed adhesive, a good general quality is sufficient. For thinner materials such as vinyl, often less than 2mm thick, an even, blemish-free finish is needed.
Floor loads and floor traffic should be established early on so that the strength of the screed needed can be worked into the specification.
A simple cement-and-sand mix is fine for a simple application, but more sophisticated mixes are suitable for a wider range of applications. Some of these new compounds can be laid on substrates other than concrete. Others, largely compounds containing latex or epoxy, can be applied to create strong screeds that are less than 20mm thick.
While pumped products allow flexibility in laying, they also make the finished screed susceptible to water damage. Protection proportional to the final use should be specified.
• Screed thickness and moisture control
Modern construction programmes do not usually allow enough time for the moisture in a new screed to evaporate. Screeds more than 100mm thick contain large quantities of water that need to dry out, failing which significant disruption late in the building process could be caused. Moisture content is important, as most floor finishes and adhesives are sensitive to it.
They are also sensitive to the build-up of water vapour if it’s sealed into the screed. Optimum screed thickness is from 30mm to 70mm as there are numerous sophisticated and versatile compounds available for this range.
Screeds can be bonded to the subfloor or unbonded. Bonded screeds are laid directly onto the new concrete subfloor or a chemical agent is applied before laying to ensure a good bond. This ensures the screed acts as one with the slab below. The laying process should be carefully undertaken to prevent de-bonding from occurring, making the screed unstable.
Thinner screeds are usually bonded. An unbonded screed of less than 50mm must be designed using a specific mix to ensure it is strong enough.
Thicker screeds can accommodate services, but it is rarely a good idea to place these directly in the screed. Feeding pipes and cables should rather be placed through a conduit, particularly heating pipes as these expand and contract.
• Movement joints
These will be discussed next. It should be noted that movement joints restrict the stress that can build up within the material, and thus they control cracking. Any movement joints should be mirrored in the screed too.
Even though a screed is not necessarily seen as a refined final floor solution, it is one of the most vital steps in flooring that plays a major role in ensuring the quality, finish and durability of the entire floor.
The gist on Joints
Concrete is a non-ductile material, which means it doesn’t stretch or bend without breaking. Interestingly, this gives it both its strongest (compressive) strength and also its weakest (flexural and tensile) strength. Concrete shrinks and expands and, depending on the building, it moves in different ways. Here is where joints play a dominant role.
Below is an overview on the types of joints, how they function and a few invaluable tips for locating and installing joints.
1. Isolation Joints
Isolation joints completely isolate the slab from something else. This could be a wall or column or a drainpipe. Isolation joints are formed by placing preformed joint material next to the column or wall or standpipe before pouring the slab. These joints are typically asphalt-impregnated fibreboard, although plastic, cork, rubber and neoprene are also available.
Failures arising from the expansion of concrete due to hot weather and sun are commonly caused by contraction joints, not sealed, which then fill up with non-compressible materials (dirt, rocks). Failure can also be due to very long unjointed systems.
For a cleaner-looking isolation joint, the top part of the preformed filler can be cut off and the space filled with elastometric sealant. Some proprietary joints come with caps to form this sealant reservoir.
Isolation joints can become water and fire hazards. In external areas such as parking decks water can easily penetrate through the isolation joints. Recommended solution is closed cell foam joints. Similarly in multi-storey buildings fire can spread through isolation joints of the floors, hopping from one floor to the next. Recommended is fire barriers in eth isolation joints.
Multipurpose closed cell foam joint acts as a waterproofing block in these isolation joints, but need to be fixed with high strength epoxy bonding agent. The closed cell foam is ideal because it absorbs vertical, horizontal and shear movements , which can occur in isolation joints
Fire barriers are becoming essential in the fire safety of buildings and similar to the closed cell foam options. The Fire barriers need to be fixed with high strength epoxy bonding agents. They are designed to be fire retardant for up to 6 hours. If used in the isolation joints, it prevents fire spreading to other floors of the building. The fire barriers can generally absorb vertical, horizontal and shear movement.
2. Construction Joints
On a job, there will always be stopping and starting and the entire slab won’t be poured all at once. This is where construction joints have a role to play. Construction joints are formed using some sort of bulkhead, made from wood, steel, plastic or precast concrete. These bulkheads are often used as screed rails during placement and finishing of the slab.
Construction joints should be worked into the overall joint plan, where they can function as contraction joints. A contraction joint should also be used in extraordinary cases of equipment breakdown, an unexpected shortage of materials, or bad weather, although the joint should still be worked into the jointing pattern – placed where a contraction joint was planned. If that’s not possible, the odd section may have to be replaced at a later stage.
There is great variety of joints that can be used in this situation depending on the type of final floor finish and the size of the sightline according to the needs of the specifier. These expansion joints are designed to withstand certain loading along with vertical and horizontal movement. Specially designed joints are used when the construction joint has shear movement. These construction joints are essential in preventing floor failures.
3. Contraction Joints
Both isolation and construction joints are formed before the concrete is poured; however, contraction joints are ‘placed’ in the fresh concrete before it has a chance to create its own joints (also known as cracks). Simply put, a contraction joint is a crack in the slab that is forced to follow a specified line. This weakness is created across the slab and allows nature to take its course. In these conditions, the slab does crack – it’s referred to as “Joint Activation”.
These joints can be laid on various grids, usually 5m x 5m, but can be as small as 3m x 3m, depending on the design of the concrete slab or floor and the movement expected. The engineer will decide on the slab design and should then advise on the contraction joint layout. Slabs and screeds usually require cut joints, however, on a floor finish such as tiles, control expansion joints or polysulphide is recommended. The control expansion joints are available in a variety of materials and generally have a much longer lifespan than polysulphide joints and end up being more cost-effective in the long run.
4. Placing Joints
Place joints under walls or carpet areas. Under walls they won’t be seen and under carpet areas the joints won’t have a chance to seep through vinyl areas. Re-entrant corners should be avoided; planning the joint pattern can often eliminate re-entrant corners.
Most plans don’t have joint spacing marked on them. Therefore it is crucial not to leave this part of the concrete construction to chance. Jointing is often not planned correctly and the cuts are placed where the installer finds it convenient.
The placing of joints is usually carried out according to the design of the building, as described above by isolation joints, construction and contraction joints. Generally, the contraction joint grid layout would be determined by the position of the isolation and construction joints.
5. Sealing and Filler Joints
Sealers and fillers for concrete joints are not the same and have very specific purposes. It is a chemical that protects floors by soaking into the pores found naturally in specific materials, clogging them so that staining agents can’t reach them.
A sealer is soft and able to accommodate the concrete slab’s expansion and contraction. Its purpose is to prevent water and dirt from entering the joint (and the subgrade) and also to prevent intrusion from below the slab. In addition, it improves the appearance of floors and slabs. More information on sealants will be shared below.
In turn, a filler is a rigid material that supports the edge of the joint when heavy traffic crosses over it. This type of material is only effective with saw-cut joints. Rounded tool edges can’t support the filler. Both fillers and sealers should be installed only after the slab has had a good chance to shrink as much as possible. Both product types should be checked at the end of the first year of service and repaired or replaced as needed.
6. Decorative Joints
Decorative concrete flatwork still needs joints to prevent cracking, which would be even less acceptable in typical grey concrete. Isolation and construction joints in decorative concrete are exactly the same as with any other concrete.
For example, when turning to stamped concrete, if the pattern has straight lines, such as slate, brick or wood-plank patterns, cut joints should follow the stamped pattern as much as possible. Some stamping contractors use custom-fabricated chisels to cut joints into the stamped pattern.
Various depth movement joints can be used – from 3mm to 30mm laid in situ – or in specific situations laid as a retro-fit joint, cut into the floor.
7. Movement Joints (Control) or Intermediate Joints
These are small joints designed to absorb localised stresses as opposed to the structural joints that accommodate the large movements revealed by a structure. There are companies that manufacture movement joints profiles have been designed to accommodate localised stresses within ceramic tile and natural stone floors, whilst the side section of the profile offers protection to the edge of the floorcovering, and the profile is manufactured in PVC, aluminium, brass or stainless steel.
The suitability of movement joints should be determined based on the anticipated movement, chemical, mechanical and/or any other stresses in the installation. The following information provides basic guidelines for the placement of movement joints if fitted in accordance with the Code of Practice.
1. For floor areas greater than 2m x 2m where the tiling abuts walls the use of a perimeter joint is recommended. It is also advisable to use perimeter joints around fixed plant or restraining structures such as columns or steps.
2. If there is an existing joint in the subfloor, then the joint must be carried through the adhesive and tile surface. If there is any stress relieving devices or crack inducers then it is advisable to have the joint in the tile surface directly above this point. If there is a change in substrate i.e. from concrete to wood, it is again recommended that a movement joint be placed at this point.
3. Taking the above points into consideration it is recommended that the resulting fields should be as square as possible.
The perfect profile should offer three characteristics:
1) Designed to protect the vulnerable step edge;
2) Increase visual awareness of the edge; and
3) Increase slip resistance.
There are three main categories of flooring sealants, namely polyurethane, water-based and solvent-based. Polyurethane creates the strongest and most permanent coating while water-based sealants are more eco-friendly with fewer toxins. However, solvent-based sealants are considered stronger than their water-based counterparts.
In addition, sealants protect a floor and increase its lifespan. Some materials will have to be sealed more often than others. This re-sealing can be reduced by pursuing a regular cleaning and maintenance regimen.
When breaking sealants down into even smaller categories, the following are identified:
o Initial-use sealer: A chemical sealant applied to a floor immediately after it has been installed. This is ideal for very porous materials susceptible to stains such as cork, brick, etc.
o Regular-use sealer: The original coat may wear down over time, requiring reapplication periodically.
o Restorative Sealant: This is a sealer that is applied to a material to reinvigorate its look. Be sure to ask the experts before trying to use this on hardwood.
o Material Limitations: Some sealants are multi-purpose and can be applied to a variety of flooring choices. Others will be more specific. It should also be noted that some recycled materials will require different sealants.
Anti-slip applications have to accommodate heavy foot traffic and require a high level of safety underfoot. Although most resilient flooring, such as laminates and vinyl, and wood floors have a natural anti-slip surface, or can be textured (e.g. Luxury Vinyl Tiles/Planks), hard surfaces such as ceramic tiles and natural stone are prone to be dangerously slippery when wet. However, developments in technology are starting to eliminate products that, when wet, pose a threat to foot traffic.
Take ceramic tiles into consideration. Thanks to technological advancements, textured tiles have been created that aren’t even close to being as slippery as original ceramic tiles. If a product isn’t manufactured with a built-in treatment, there are modern chemical treatments available to alleviate this problem.
These chemicals provide a deep-etching effect that is almost invisible but abrasive enough to prevent falls. Their surfaces are also clear, and therefore don’t affect the colour or design of the floor.
Anti-slip strips can be fixed to flooring. There is a large range of stairnosings available with anti-slip features helping to ensure slippery stairs remain safe.
Detailing on skirting boards adds significantly to a project. Skirtings, albeit a small detail, can make all the difference to the interior of a room. They define the character and style of the room and can also hide services such as pipework or electric cables.
The following three skirting options should be considered:
1. MDF Skirting
It is easy to install and widely available either pre-primed or pre-finished. MDF has become a popular choice as it is also resistant to warping and swelling, making it a low-maintenance option. MDF skirting is affordable and very easy to finish as a result of its smooth surface.
2. Softwood Skirting
While softwood skirting is more susceptible to movement than MDF, it offers a number of advantages. It can be stained or varnished to provide a natural look and can be sanded down and refinished, which is why it doesn’t require frequent replacement.
3. Wood Veneered Skirting.
Wooden veneered skirtings are Eco friendly and comprised from finger jointed spruce wood. This ensures low warping and guarantees the highest stability, which is wrapped with 2mm prime quality hardwood veneer. It is also available in a greater variety of hardwoods and have an easy to fit Clipstar mounting system, allowing the skirting to be removed and used elsewhere if required.
4. Hardwood Skirting
Hardwood skirting offers a top-end look. It is an obvious match alongside oak floors, etc. Alternatives include ash, beech and walnut. Hardwood skirting is available pre-oiled or pre-stained if required. It is also more resilient against knocks and scuffs, making it a low-maintenance option.
Fitting hardwood boards is more complex than MDF or softwood, typically involving pre-drilling the timber, screwing into wall plugs and plugging the screw heads with real wood pellets.
Once screeds, joints and the final floor has been installed, trims are the next step to add to the floor’s look and feel. Trims are long, thin strips of material, which have been shaped to fit at the end of the flooring. Trims are a necessity, not a luxury – if a floor meets up with a wall, it will need a trim. When one floor meets with another between two rooms, a transition piece is required. They will also be required at doorways and/or stairways.
Various Trims are identified:
Also called skirtings, they do not cover the expansion gap between the floor and the wall and another piece will be attached to that.
Quarter Round (Wood & Laminate)
The shape on the end is one quarter round with the flat sides resting on the floor against the wall.
Wall Base (Vinyl & Carpet)
This is equivalent to baseboard/skirting but just made of plastic or rubber.
Bullnose (Tile & Stone)
Also equivalent to boards/skirtings, this trim is made of stone or tile.
Transition Pieces that are inserted between wood and laminate flooring.
This is installed to cover the expansion and contraction that will occur in the above flooring types and ensure that gaps are not left in the floor.
End Cap (Wood & Laminate)
This product lies over the edge of the floor then drops straight down, “ending” the floor. It is used against cupboards, sliding doors and walls.
Reducer / Transition (Wood & Laminate)
The bottom of a reducer (transition) has two levels and is designed to rest squarely on two different levels of flat flooring. It typically offers a 6mm height difference.
Threshold/ Ramp/ Finish (Any floor made of wood, metal or stone)
Used at exterior doorways or where a reducer (transition) is too small to cover the level differences. This can be from a height difference of 6mm to 14mm.
T-Mold / Expansion (Wood & Laminate)
It is similar to a reducer (transition), but used on level flooring to take up expansion.
These finish off the edge of a step, and have to be used when laminates have been installed on stairs. They protect the gap on the riser and tread.
Dirt-trapping mats are essential in ensuring that a floor remains clean and in pristine condition. These mats can be professionally designed and installed and customised to meet the size, type, and material criteria to cater for traffic.
These mats trap a significant amount of dirt, and any dirt not trapped will be transported into the building, however, this will be minimal. Dirt on the actual floor has to be removed by means of a thorough maintenance and cleaning plan to ensure that the lifespan of the floor is not affected.
Epoxy floor coatings are hardwearing and durable for both commercial and industrial flooring. These coatings can be applied over concrete floors to provide high-performance and attractive surfaces. For example, such a coating creates a high-gloss concrete floor.
A new epoxy floor coating creates an easy-to-clean, seamless and attractive flooring surface. It also creates a chemically resistant surface, improves safety (by creating a slip-, impact-, heat- and fire-resistant flooring solution), allows for designated traffic and work zones (using different colours of epoxy floor coating products at the same time to define zones) and increases productivity capabilities. This is because it allows for faster material movement.
Maintenance and Cleaning
After every single specified product included in the final flooring solutions mentioned above has been installed, a maintenance programme must be designed and implemented. It is absolutely critical to follow the manufacturer’s instructions, as these will prevent unnecessary damage.
For larger commercial and industrial spaces, specific machinery is available that will achieve results in these programmes.
The low-speed swing machine is used more often as it is versatile, cost-efficient and easy to use. They can be used for stripping, scrubbing, buffing all types of floors and sanding wood floors.
These are designed to generate heat and friction that will smooth and harden floor finishes, creating a “wet” look. This hardened look is easier to maintain and will withstand more abuse. Even though burnishers are more expensive than swing machines, they provide long-term financial benefits.
These are better for cleaning natural stone tile or concrete floors and last longer. Pads are better for buffing and burnishing but will also effectively strip and scrub. The darker the pad, the more aggressive the action.
This comprehensive list of topics discussed above clearly demonstrates the unique role each plays in ensuring that the final floor solution is a long-term success.
Acknowledgment and thanks are given to the following for the information contained in this article: Flowcrete SA; Genesis Global Systems Limited; Kirk Marketing; TAL; www.concretecentre.com; www.building.co.uk; www.concretenetwork.com; http://flooring.about.com