Frequently Asked Questions

PAGE10 : INSTALLATION CRITERIA

Q. How is a raised access floor installed?
A. With regard to the physical installation of the raised access floor within a basic space there are two main issues:

• Finished floor height and level. Within a single floor area a datum height will be agreed between the floor installer and the main contractor. This datum height will be directly related to the building datum. This will determine the height to which the raised access floor will be installed. The raised floor will be installed level to this datum by the use of rotating laser.
  
• Set out of the raised access floor system. The set out of the raised access floor is an important aspect in ensuring that the raised floor operates satisfactorily throughout its anticipated life span. Depending on the size and shape of specific floor areas and size and location of any obstacles on the sub-floor a range of solutions can be sought. Raised access flooring panels are cut on site to fit at perimeter walls therefore a best fit situation can be sought using the appropriate floor panel module size. Ideally the setting out of the panels and pedestals can be co-ordinated by:
  
• Working in line with other building modules to avoid regular obstructions.
• Working out from the centre of an area.
• Working to column centres.

Cut panels should ideally be cut just under a full panel width or a half panel width in order to minimise wastage. Cut panels of less than 150mm width should be avoided in order to maintain structural integrity. When it is not possible to avoid small cut panels the following solutions are available:

• In-board cutting, the principle of maximising the size of a cut panel by additionally cutting the last field panel adjacent to the perimeter. On certain product ranges and structural grades oversize panels are available as an alternative to the above.

Q. What are the site requirements?
A. The following site conditions are required for the installation of a raised access floor:

• Dry and watertight areas at a temperature above 5°C and a humidity below 75 % RH. This is required for both the installation works and also for material storage.

Sub floor to be in the following condition:

• Free from wet or dry contamination.
• Able to accept epoxy resin pedestal adhesive and if required mechanical fixings.
• Any holes, joint lines etc in higher level sub floors should be sealed in order to prevent floor sealer leaking through to the level below.
• The sub floor should be structurally strong enough to support the raised access floor and the environment it supports.
• The sub floor is required to be structurally strong enough to allow the storage of raised floor materialsprior to installation (note; palletised materials typically weigh 400kgs and stand 1200mm high and are 650mm square).
• The surface of the concrete sub floor should ideally be of a medium tamp finish in order to give a reasonably flat surface without inducing the formation of weak surface laitance.
• A power float finish will normally give a excessively smooth surface which will prevent the dust sealer and the epoxy resin pedestal adhesive obtaining a good key and hence good bond onto the floor surface. In order to achieve a good bond onto a power float finish the subfloor will require to be suitably prepared by mechanical means which will remove weak surface laitance and provide a suitable surface for the application of floor sealer and pedestal adhesive.
• Light weight structural sub floors such as Lytag need to be treated with caution with regard to their compressive strength and also the fixing of pedestals to their surface as failure can occur due to the weakness of the sub floor rather than the integrity of the pedestal fixing.

General working conditions include:

Q. What are the potential timeframes?
A. The timeframes associated with the installation of a raised access floor are affected by many factors as outlined below:

• The size and shape of the areas into which a raised floor is to be installed.
• The exact specification of the raised access floor that is to be installed.
• General condition of the building.
• Poor quality of sub floor.
• Building programme and sequence of installation amongst other works.
• Manufacturing times for raised floor components.
• Obstacles on the sub floor that have to be worked around.
• Availability of work areas.
• Unloading and distribution conditions.
• Availability and approval of necessary information.

Until these factors are suitably assessed for a specific project only then can installation timescales be evaluated. However an indicative installation rate of 500m2 per week would be considered acceptable for an ‘average’ installation.

Q. Is it necessary to apply protection to the raised access floor?
A. Various factors surround the use of protection in relation to raised access floor installations. Generally protection should be used:

• To all installations where the floor panels have a factory bonded finish.
• To all areas where the floor panels will be heavily trafficked prior to the installation of the soft finishes i.e. carpet tiles.

Generally protection may not be required:

• To areas where the floor panels will not be heavily trafficked prior to the installation of the soft finishes.
• To areas where significant repeated access is required to the floor void for the installation of services.

Materials commonly used for floor protection:

These will be laid on the floor and if required the joints will be taped. Plywood and hardboard will provide protection against heavier levels of traffic than plastic sheet however their removal for access to the void is more difficult.