How raised floor systems work

Adjustable height pedestals can both be used for raised tile flooring / decks. The cost advantage of pedestals alone has to be weighed against the practical advantages of a substructure.

PEDESTAL AND RAISED FLOOR TILES

John Gill

9/3/20256 min read

What is a raised flooring system?

A raised flooring system is a floor/deck constructed on a platform above the substrate. Sometimes called floating floors because they are not fixed to the substrate. Most used over a waterproof membrane they incorporate adjustable height pedestals to achieve the desired height. Tiles, timber, artificial grass, bamboo and composites are used as the finish material. The substructure can be joists on adjustable pedestals, or pedestals only.

The significant advantages in raised flooring systems have led to them becoming the most commonly used option for level flooring in outdoor areas. Areas that were previously unused (such as rooftops) are now included in the landscaping of the property with the inclusion of a raised flooring system.

Most of these installations are in areas with a low finish height that do not allow for the use of timber. The increase in quality of adjustable pedestals and aluminium substructure systems allow floating floors to be constructed over waterproof membranes and provide opportunities that were previously unavailable. When combined with the improvement in composites, artificial grass and structural tiles, long lasting, useable areas become viable and cost effective.

Advantages of raised flooring systems (decks).

In a nutshell, raised flooring systems are a cost-effective way to cover ugly, unusable, dangerous or unpractical substrates and transform them into useable, multipurpose and level surfaces that can enhance the looks and use of the area. The deck "floats" above the substrate independently and slopes for drainage are all under the deck.

Raised flooring systems are ideal when used on roofs, balconies, over carparks and other areas where weight is an issue, eliminating the requirement for sand and cement bedding and can easily be retrofit. Raised flooring systems are strong and can be used underneath planters, spas, pergolas etc. They are ideal over waterproof membranes as there is no requirement for substrate penetrations.

Raised flooring is a quick and highly efficient solution to areas where excess water can be problematic (such as balconies, green roofs, water features, pool areas, etc.). The small gap between each slab or tile allows for quick water drainage where water is collected onto the surface underneath for rapid drainage and easy access for waterproofing. The lack of a cement bed or mortar means that phosphorus and efflorescence issues are a thing of the past.

Areas with drainage issues

No more ugly staining

Perfectly level surfaces don’t happen often in building and construction. So, if sloping or uneven substrate is causing you problems with your latest build, here are 15 reasons why you should use a raised flooring system.

Cost effective: Eliminates cost of surface preparation plus lower installation costs
Fully adjustable: You can easily create a level surface by adjusting the supports, to compensate for unevenness, irregularities or gradients on the laying surface. You can even bridge openings and gaps.
Water drains quickly: The gap between each slab or tile lets water discharge onto the laying surface to facilitate fast and efficient drainage.
Structural movement is absorbed: As the floor is independent of the structure, the paving and supports absorb any expansion or structural movements.
No penetrations through the waterproof membrane.
Protection of waterproof membrane by covering it with a trafficable surface and no exposure to UV
Ability to have the external and internal flooring at the same height. – step down not required
Reduces noise: The supports’ anti-slip and anti-noise rubber can reduce sound impact by up to 25dB.
Environmentally friendly: No chemicals are used in installation and at the end of its service life, the system can be fully recycled.
Improves thermal insulation: The air circulating between the paving and waterproof membrane extends the life of the membrane and improves heat insulation.
Quick to install: The system can be installed quickly and easily, with little site preparation and minimal disruption to the build site.
Provides easy access and concealment: The gap between the floor and membrane allows for easy access and concealment of plumbing and electrics.
Low in weight: As a levelling bed is not required, the weight is reduced to being just over the weight of the finish product.
Minimal preparation: No requirement to demolish existing floor surface. E.g. Can be constructed
No Efflorescence or mould in grout with concrete tiles.

Advantages of tiling on pedestals or raised substructure

Thermal Insulation

Pedestal tile showing services under the tile

Movement absorption - No cracks

Lower weight compared to traditional tiling

Easily accessible services

Pedestal tile showing easy surface water drainage

Allows for substrate level changes yet provides a level surface

Acoustic Insulation

Tiles and pedestals are Reusable and recyclable

No grout between tiles - Creates excellent drainage.

There are two systems for creating a raised tile access floor. Both systems use adjustable pedestals to achieve the desired height.

The first system uses pedestals only. The pedestals are placed on the substrate and adjusted to create a level finish height across the top of the pedestals. Structural strength pavers or tiles are then placed on the pedestals and supported at each corner. It is common to use an additional pedestal in the centre of large tiles for additional support.

The pedestals space the tiles or pavers evenly and raise them off the existing surface and create a flat, useable deck or floor area at the same time as creating a void between the paving and the membrane. The void encourages constant air circulation and allows for the substrate to be sloped for water drainage.

The second system uses a substructure in the same way as you would construct for a timber or composite deck. The difference is the spacing and the joists are topped with rubber to stop tiles slipping. Aluminium joists are most commonly used due to their stability and straight lengths. Pedestals are placed under the bearers or joists and adjusted to level. The tiles sit on the joists and are held in place by plastic or stainless clips.

One of the advantages in using a substructure system is the long term stability of the tiles. The tiles will not rock or move and therefore provide a firm and stable platform for pedestrians. The other advantage of a substructure system is the ability to span a greater distance and / or cover gaps, substrate irregularities and services.

With both systems, the void between the tile and substrate is often used to run HVAC, electrical and plumbing services. Both systems, (Pedestal and substructure) are designed to allow the tiles to be lifted for under floor access. This is particularly handy for inspecting waterproof membranes and maintenance of services. It also allows for cleaning and troubleshooting other building issues.

SafePave can be used with both systems. It enhances the structural integrity of the tiles making them stronger and safer. SafePave also adds to the insulating effect of the void at the same time as reducing any vibration noise.