Raised Access Floor Installation - Data Center Floor Tiles

Recommended Equipment and Tools

It is the responsibility of the Installation Contractor and their crews to protect the installed product until the installed area or section is turned over to the General Contractor, Owner or Owner’s representative. For raised access floor installation, exercise caution and good judgment when transporting and working with tools, tool cribs, gang boxes, pallet jacks, portable saws and band saws, or any other equipment on top of the raised floor.

Other trades are also to be cautioned as to acceptable work practices on top of the access floor. Continuous sheets of 4’ x 8’ plywood with a minimum ½” thickness are recommended to protect the floor from all trade work and construction traffic conditions and to cover floor openings such as where floor box access tiles are installed.

Recommended Power Tools and Equipment (number of each):

(1) Torque Adjustable Power Drill, 3/8” chuck
(1) Adjustable Power Drill, ½” chuck
(1) Builder’s transit or laser level (Spectra Precision 1485 HP or equal)
(1) 20-inch wide pallet jack
(2) 50-foot extension cords
(2) 100-foot extension cords
(1) 14” throat, metal cutting band saw, 450ft per minute cutting speed
(6) Band saw blades, bi-metal cutting, 14 tpi, wavy set ½” wide, 0.030 thick
(1) Suction Cup Lifter
(1) Industrial grade vacuum cleaner with fittings

Site Preparation

The efficient raised access floor installation requires control of the area where the work is to be undertaken. It also requires that the General Contractor, Owner or Owner’s representative be aware of and understands the following conditions.

1. Storage Conditions:

a. Before installation commences, material must be unloaded and staged as close as possible to the actual installation area. The General Contractor, Owner or Owner’s representative must provide a closed, dry and secure storage area. This area must be accessible to freight elevators and/or hoists and have a clear path to the installation area(s).
b. The storage area must be closed to the outside weather with a minimum temperature of not less than 40° F and not more than 95° F (4° C to 35° C) with a relative humidity level between 20% min. to 80% max. maintained at all times, as the access floor and its accessories are an architectural interior finish and not a base building structural component.

2. Site and Temperature Conditions:

a. The installation area(s) must be closed to the outside weather conditions with a working temperature between 50° F to 85° F and a relative humidity (RH) between 20% and 60% for at least three (3) days prior to, during and after the entire installation period.
b. Material taken from the secure storage area must be staged in this environment before being installed. It is recommended that the installation area be as close to the normal operating RH and room ambient temperature as possible, so as to acclimatize the components prior to assembly and placement.
c. Adequate space lighting and a minimum 110-volt, 20-amp supply power must be made available during the installation.

3. Substrate Conditions and Acceptance:

a. The subfloor must be clean and free of moisture, dirt, grease, oil or other debris that would hinder placement of the pedestals on the substrate.
b. Check for final level of the substrate. Levelness is defined as the degree that the floor varies or slopes from true plane over the length of the area.
c. Check for final flatness of the substrate. Flatness is defined as how smooth the surface is over a true plane, using a 2-foot straightedge per ACI 301 Tolerance Class C. Site inspection of the subfloor areas with a straightedge and pedestal can easily determine problem sections.
d. All low areas (chipping, spalling, curvature, valleys, etc.) must be filled and sealed with a high quality floor patch, if the conflict with the pedestal grid layout.
e. High spots (exposed aggregate, curvature, hills, etc.) must also be repaired with a floor patch or self-leveling, Portland-based cement. If the concrete substrate has been leveled, bull floated and final floated, but not trowelled or broom-finished, it may be possible to spot grind the applicable area to and acceptable flatness.

4. Other Substrate Materials:

a. If applicable, check wood subfloors for any excessive deflection that will transfer to the access floor tile surface and seem spongy under floor or castor traffic. Wood subfloors, unless braced or strengthened, also tend to creak and generate noise.
b. If applicable, existing subfloors with floor finishes such as vinyl composite tile (VCT) should be examined for adhesion to the substrate and re-installed if loose, or replaced, if damaged. A suitable floor patch can be used in lieu of VCT tiles.
c. If applicable, Vinyl Asbestos tiles (VAT) and the tile adhesive with asbestos fibers must be removed, repaired and/or sealed by others qualified to conduct the asbestos abatement program within the project’s jurisdiction, before the access floor installation commences. The Access Floor Installation Contractor shall receive written confirmation that the area is sage to work in and inhabit. Follow the recommendations of the asbestos abatement program guidelines if a mechanical anchor is being specified, as there may be asbestos dust from drilling anchor holes.

5. Contract and Shop Drawings:

a. Check the size and configuration of the floor area to the contract drawings and mark all measurements on the drawings accordingly. Review and obtain agreement from the General Contractor, Owner or Owner’s representative concerning size, trade or architectural obstacles or changes in space configuration.
b. Confirm that the access floor starting point is in agreement. Refer to the section on Installation to properly establish room squareness.

6. Installation Access and Architectural Elements:

a. Ensure that the access floor installation, as scheduled, will be free of other trades and that their material are, or will be, cleared form the installation area(s).
b. Locate and mark all distribution service elements (power, voice, data, plumbing, perimeter HVAC wall mounted convection units, etc.) that may conflict with the pedestal grid locations. Reach an agreement with the other appropriate trades on how to handle any such obstructions and determine the schedule to correct these conflicts.
c. All overhead work is to be completed prior to the installation of the access floor.
d. Any subsequent work which will use the access floor as working platform much protect the access floor with suitable load bearing protective materials, whether or not that section or area of access floor installation has been accepted.

7. Access to Completed Areas:

– Notify the General Contractor, Owner or the Owner’s representative (those responsible) that no trade personnel other than certified access floor installation mechanics shall be allowed on the completed section(s) until:

a. The perimeter of the section is enclosed on at least 3 sides by permanent floor to ceiling walls or other such permanent architectural elements to prevent shifting of the access floor grid lines.
b. The access floor, or portion thereof, has been inspected and accepted by the General Contractor, Owner, or Owner’s representative and so recorded.
c. All trades working on top of the completed access floor installation protect the surfaces by placing down continuous sheets of 4’ x 8’ plywood, or other suitable load bearing material, with a minimum thickness of ½.

8. Cleanliness of Access Floor and Cavity Spaces:

– The access floor and cavity space will be clear of dirt, dust and debris upon completion of each area and as accepted by the General Contractor, Owner or Owner’s representative.

Raised Access Floor Installation Methods and Techniques

Getting Started With Your Raised Access Floor Installation

Step 1 – Verify Dimensions and check subfloor:

1.1 Check the room or area dimensions to the approved contract drawings.
1.2 Check the level of the subfloor with a laser level or builder’s transit. Check variations to established architectural reference points where the access floor will abut or terminate, such as doorways, sills, recessed concrete slab edges, columns, elevator shaft(s) or some other permanent interior architectural building element. Notify the General Contractor, Owner or the Owner’s representative (those responsible) if the access floor cannot be installed per the contract drawings.
1.3 Check the subfloor flatness. Do not proceed with any aspect of the installation until irregularities have been corrected.
1.4 Consider cable management floor options for the subfloor plenum area

NOTE: Starting the installation before corrective actions by others are satisfactorily completed may automatically indicate acceptance of the subfloor “as is” and the overall responsibility to correct the substandard conditions.

Step 2 – Establish the “STARTING POINT”:

2.1. Locate and mark the starting point ( ) indicated on the contract drawings.
2.2. From the starting point, snap chalk line “A” along wall no. 1 (longest wall) at 24” from the wall.
2.3. From the same starting point, snap a temporary trial chalk line “B” along wall no. 2 (shortest wall).
2.4. Make continuous measurement checks of the distance from the wall for both chalk lines.
2.5. If the distance exceeds 24”, due to irregularities in the face of the wall, move the line closer to the wall to make sure the maximum distance does not exceed 24”. “

Step 3 – Establish a square condition (90⁰ angle) for control chalk lines.

3.1. The following steps will assure that the raised access floor installation will be square relative to the room. The access floor gridlines must be squared by the installer, using the “3-4-5” method of triangulation.
3.2. From the starting point, choose the longer wall and measure the longest possible distance along chalk line “A” to establish the first side of a “3-4-5” triangle and mark this location as “Point 1”.
3.3. From the same starting point, choose the shorter wall, adjacent to the first wall and measure a distance along chalk line “B” that will be appropriate to establish the second side of a “3-4-5” triangle and mark this location as “Point 2”.

Step 4 – Place Supports:

4.1. In both directions, measure ten-foot grid increments from the starting point and snap chalk lines perpendicular to each control line. This creates the outline of the pedestal grid and the points of intersection at 10’ on center (o.c.).
4.2. Place all intersecting grid line pedestals in their approximate position.
4.3. Within the initial 10’ x 10’ grid lines, lay out and mark the locations of the:

a. Architectural and Power components.
b. Zoned Cabling components.
c. Bridge Beam supports being secured to the substrate.

These locations will be indicated on the contract drawings and should be referenced from permanent architectural elements such as columns.

4.4. Using a laser level or builder’s transit, shoot the pedestals to the proper elevation at each of the grid line intersections.
4.5. The 10-foot leveling bar will span these leveled control pedestals and is used to set the infill pedestals on 24” centers between these grid points. Set the four-(4) infill pedestals at 24” centers under the leveling bar and adjust each pedestal head up to the bottom of the leveling bar. Do not raise or knock the leveling bar as you install the infill pedestals between the control pedestals.
4.6. After two (2) grid line rows at 10-feet apart have been placed, turn the leveling bar 90 degrees to position the infill pedestals between these control rows. You will repeat this raised access floor installation pedestal sequence for each 10’ x 10’ grid as you complete the “Basic L”.
4.7. Glue each freestanding pedestal base that has been set in place and leveled. Use an adhesive spatula or similar device to place the adhesive onto the subfloor.

A pedestal assembly, firmly attached to the structural substrate (concrete slab, floor, structural steel bridging), shall be located under each panel corner, whether full module panels, or modified/cut panels at perimeter walls, columns, equipment, etc.

Tilt the pedestal to 30 to 45 degrees and be sure to keep one pedestal base side on the substrate. This tilt method helps ensure that the grid spacing of 24” O.C. is not disturbed as the adhesive is applied.

Use a slight hand pressure and twist to embed the pedestal into the adhesive. The adhesive should flow out and show a slight bead on at least three sides of the pedestal.

This bead of adhesive will be from 1/16” to about 1/8” in size. This method ensures full adhesive spread over the bottom of the baseplate.

Pedestal Adhesive Open Times:

The pedestal adhesives will start to setup and cure once they are applied. The actual cure rates will vary with the room ambient temperature, the substrate temperature, the concrete moisture content, concrete sealer application and the relative humidity of the space. The period of open time of the adhesive in which the pedestal bases can be moved for minor grid or levelness adjustments and then reseated into the wet adhesive will also vary depending upon whether or not the compound requires a solvent release or moisture cure reaction. A solvent release requires evaporation of its solvent to cure therefore excessive moisture conditions slows the cure rates. A moisture cure compound is the opposite reaction in that excessive moisture conditions will speed up cure rates and reduce the open time available for minor adjustments.

At 72 degrees F and 40 to 45% RH, the following open times are typical:

Aim 382 Adhesive, solvent (water) release 40 to 50 minutes.

Michigan Adhesives, Sealbond #95, moisture cure 20 to 30 minutes.

Moving the pedestals for adjustments after the open time has expired may require additional amounts of adhesive to reseat and bond the pedestal base.

Always be aware of the open times of the specified adhesive to the actual site conditions.

4.8. Pedestal Adhesive and Mechanical Anchors:

Always use pedestal adhesive where mechanical anchors are specified for seismic conditions or other requirements such as lateral braces. The adhesive affords the raised access floor installation installer the opportunity to hold the grid in place, make minor adjustments as the installation progresses and compensate for subfloor undulations.

Allow the adhesive to set for at least 48 hours from the time of last pedestal placement in the room or area before installing anchors. The set-up period allows the baseplate and adhesive to cure, conform to the substrate undulations and act as a gasket as the mechanical anchors are tightened.

On every other row, remove up to five (5) panels at a time to access the bases. Drill holes as per the specified manufacturer’s instructions and be sure to use the proper bit OD to anchor OD and hole depth. The anchors will be placed on two (2) opposite sides of the pedestal base tube to prevent concrete failure. Cut pedestal based due to infill or obstruction conditions must maintain the minimum anchor spacing as recommended by the manufacturer unless instructed by others to treat these conditions differently.

Secure the anchors to the manufacture’s recommended torque. Alternate fastening between two anchors until the torque setting is achieved. Use caution so as not to shift or pull the pedestal grid alignment and vertical plumb of the pedestals themselves.

4.9. Stringer Applications:

Attach stringers to the leveled pedestal head with a torque controlled screw gun. Set torque to 40 inch-pounds. Do not over fasten the stringer screws. This can cause the bottom of the stringer to flare outward and can make the system tight as panels are placed into the stringer grid.

Stringers must be squared to the pedestal head. If the stringers are skewed or cocked at the time of installation to the pedestal head, the stringers will be out of square to the pedestal grid and you will not be able to maintain the visible panel grid lines on the walking surface of the access floor installation.

Install the stringer grid pattern as specified using 2’ and/or 4’ stringers. Be sure to attach cut end of stringer to pedestal head using self-drilling/threading screw from below.

Stringers which are field cut at perimeter walls, columns, equipment frames etc. where the screw hole portion has been cut away, shall be positively attached to the perimeter pedestal head by either re-drilling a stringer screw hole and attaching accordingly, or using an appropriate sized self-tapping metal screw.

4.10. Setting Panels and Creating the Basic “L”:

Once the first 10’ x 10’ grid has been installed, leveled and checked for squareness, install the three (3) adjacent infill panels against the wall in order to secure the grid. Cut the infill panels 1/8” short of the actual dimension to allow for building expansion and contraction. This 1/8” void will be covered by a cove base to be installed by others. At this point the pedestal adhesive will not have achieved its full bond strength, so it is necessary to place wood shims in the void to prevent shifting. Remove these shims after 48 hours.

4.11. The remaining 100 square foot grid sections are installed and sequenced in an “L” configuration within the room or space. The “L” simulates a 90° carpenter’s square and is used to maintain square of the entire field relative to the initial control lines as installation of subsequent grids progresses.
4.12. From the Starting Point and along the longest wall, place the tiles within the next adjacent 10’ x 10’ support pedestal grid area. Make sure the tile edges along the wall stay reasonably aligned on the control line. This would be Section B 2 in the diagram.
4.13. Create the long section of the “L” first. Continue to install grids and ensure that the “L” is maintained as installation progresses.
4.14. Stockpiles of pallets or skids containing the access floor panels should be staged within 10’ of the grid areas and no closer than 10’ apart, in both directions, to ensure that the structural subfloor is not overloaded. Check with those responsible that the pallet weight and the dead weight of other packaged components are within the concentrated and uniform load capabilities of the building slab or floor.

NOTE: Always exercise caution when moving or handling stacked panels to prevent slipping or toppling.

4.15. Raised Access Floor Installation Mechanics and their helpers should always be mindful of installation efficiencies in terms of placing pedestal and panel stocks ahead of actual tile placement and within reach of the installer.
4.16.a. Control Tile Grid Lines Between 100 Square Foot (10’ x 10’) Sections:
a. From one (1) to three (3) rows out from the starting point, attach a dry line, in both directions, across the walking surface of the panels directly over the edge seam of two abutting panels.
4.16.b. Raise the dry line above the panel surface by placing a pedestal on the walking surface.
4.16.c. Run the dry line and attach the ends to columns or the drywall surface of permanent walls with #10 sheet metal screws. Make sure the dry line is taunt and support with more pedestals as necessary along the dry line to provide intermediate support.
4.16.d. These dry lines will be continuous and moved along each 100 square foot section of grid as installation commences. These visual controls will prevent the “L” as described in Step 4.10 from drifting off the snapped chalk lines on the substrate.

Other Special Conditions

Partition Walls:

1. Fire-Rated walls must be continuous to the base building structural floor and are not to be installed on the access floor.
2. Demountable partitions and fixed stud wall construction can be installed on the floor. As with any type of raised floor, do not use powder activated fasteners to install the wall or partition base channel to the panels as the magnitude of the impact can permanently deform the tile surface.
3. Pre-drill base channel mounting holes and secure per the manufacturer’s instructions. It is recommended that blunt tip screw fasteners be used so as not to damage any cable runs that extend under the wall location.
4. Partitions that are taller than 72” in height may be subject to seismic requirements. If applicable, check with those responsible before proceeding.
Grounding of the Access Floor System:

1. Electrical Ground Requirements:

a.The Access Floor System can be connected to the building equipment ground subsystem. A grid network of equipment ground wire connections can be made to the pedestal based on the electrical specifications for this project. This equipment ground network is typically #6 AWG ground wires and should be installed by a licensed electrician.
b. Under no circumstances shall the Raised Access Floor Installation Contractor assume responsibility for conducting this work unless a licensed electrician has been separately subcontracted for this specific purpose under the scope of the access floor installation work.

2. Static Electrical Requirements:

(For Information Purposes Only)

Requirements for specific statical electrical properties involve the floor covering specified for the project and not the raised floor.

Raised Access Floor Installation Punch List and Final Inspection:

1. Inspection: The Access Floor System must have a solid feel underfoot Replace or repair any damaged parts, accessories and defects in workmanship. Obtain building owner, agent or general contractor acceptance of the completed section before any loads are applied or subsequent trade work such as carpet commences.

2. Safety and Protections: The raised access floor installation system shall be protected from damage or work conducted by other trades until the final inspection has taken place. Plywood or other suitable load distribution material shall be laid in hallways, corridors or any material passageway entering the raised floor area.

Always know your raised floor installation floor height, need for data cables, load rating and desired feet high. The feet high profile cable management determines floor height. The height profile floor determines easy access to understructure components. Tye type of access floor required is determined by a variety of raised flooring solutions. Raised floor panels are available now at DCFT.

* Guide is for reference only. Always contract a certified installer before attempting to install a flooring system. Refer to the ASM Raised Access Floor Installation Guide for additional drawings and details. See ASM PowerTraxx Installation video below for low-profile access floor installation.