Sheet I-100 · Installation
Installing a rooftop cable tray, start to finish
This is the sequence a project manager should hold the crew to. ANDREW's public spec sheets don't include install steps. Those are in each kit's assembly drawing, which ships with the kit or comes from your ANDREW representative. So this page is general industry practice, set out in the order the work happens. Where it and the assembly drawing disagree, the drawing wins.
Governing documents, in order of precedence: (1) the authority having jurisdiction and the permit set, (2) the engineer of record's structural/wind letter, (3) the roof manufacturer's written requirements, (4) ANDREW's assembly drawings, (5) the owner or carrier construction standard, (6) this page.
1. Pre-construction survey
- Roof system: membrane type (TPO, PVC, EPDM, modified bitumen, BUR or coated), age, condition and insulation. Note any soft or wet areas, and photograph everything before you start.
- Roof warranty holder: find out who issued it, whether it's still in force, and who the roofing contractor of record is. You need their requirements before you finalize the layout.
- Route: measure the true path from equipment to the building entry. Note drains, scuppers, crickets, expansion joints, curbs, HVAC service lanes, roof hatches, skylights and parapets.
- Structure: deck type and the framing direction under the route. The engineer needs this for the dead-load check.
- Access and hoisting: crane pad or hoist point, the landing zone over structure, and the street/right-of-way situation.
2. Roof-warranty coordination
The roof warranty is usually worth far more than the tray. Before mobilizing:
- Send the layout, the sleeper/pad materials and the hood-entry detail to the roof manufacturer or roofing contractor of record. Get approval in writing.
- Confirm the protection layer under each sleeper (walkway pad or slip sheet) is compatible with the membrane. Rubber and PVC aren't compatible with every membrane. PVC membranes in particular have chemical-compatibility limits, so get the exact pad approved.
- Any opening, curb or flashing, including the MT-365G hood entry, is roofing work. Have the roofing contractor of record do it, or have them inspect and sign off on it.
- Book a roofer inspection for after the install and keep the sign-off for closeout.
3. Structural and wind review
- Give the engineer of record the dead load. It's the hardware weight per foot from the estimator, plus the cable weight per foot from the cable spec sheets, plus ice or water if they apply. Bridge kits run about 9.6, 14.0 and 22.5 lb/ft of hardware for 4, 8 and 12 runs (net weight ÷ 8 ft).
- No part in the line has a published wind rating. Ask ANDREW for one in writing. Without it, the engineer has to design ballast or attachment for uplift and sliding at the site's design wind speed. See Texas wind.
- Check point loads at the sleepers over the insulation's compressive strength. A soft insulation board can crush under concentrated loads.
4. Permits and submittals
Pull permits as the AHJ requires (in San Antonio, see permits). Submittal package: the spec sheets with their revision dates, the assembly drawings, ANDREW's wind-rating response, the engineer's letter, the roof manufacturer's approval and the lift plan. The full list is on the checklist.
5. Delivery, storage and lifting
- Inspect at delivery and note any damage on the bill of lading before you sign. Shipping mishandling is excluded from the warranty (§8(k)), so the claim goes to the carrier.
- Keep the packing slip. The ship date starts the one-year warranty clock.
- Store galvanized steel dry, off the ground and with air between pieces. Nested wet steel develops wet-storage stain ("white rust").
- Lift kits to the roof, never drag them. Land loads over structure, never mid-span, and spread them on plywood over the membrane.
| Part | Description | lb | kg | L × W × H |
|---|---|---|---|---|
| MT-365G | Rooftop Hood Entry Kit | 229.942 | 104.3 | 49 × 34 × 32 in |
| MT-F1595 | Rooftop Coaxial Cable Bridge Kit, 12 runs, 12-gauge cover | 180.338 | 81.8 | 96 × 35 × 7 in |
| RT-CB12D | Rooftop Cover Kit for SnapStak Snap-in Hangers, 12 holes | 162.48 | 73.7 | 96 × 36 × 11 in |
| RT-ST | Rooftop Cable Tray Step-Over | 146.387 | 66.4 | 70.5 × 41.5 × 13.2 in |
| RT-CB8D | Rooftop Cover Kit for SnapStak Snap-in Hangers, 8 holes | 122.577 | 55.6 | 96 × 28 × 11 in |
| MT-F1543 | Rooftop Coaxial Cable Bridge Kit, 8 runs, 12-gauge cover | 112.215 | 50.9 | 96 × 30 × 7 in |
| RT-CB4D | Rooftop Cover Kit for SnapStak Snap-in Hangers, 4 holes | 85.98 | 39 | 96 × 20 × 11 in |
| MT-F1542-11 | Rooftop Coaxial Cable Bridge Kit, 4 runs, 12-gauge cover | 76.721 | 34.8 | 96 × 20 × 7 in |
| MT-F1704 | Extension Kit for Bridge Kit, 8 runs | 39.022 | 17.7 | 40 × 24 × 20 in |
| MT-F1703 | Extension Kit for Bridge Kit, 4 runs | 29.983 | 13.6 | 40 × 12 × 20 in |
| MT-F1597 | Adjustable Splice for Bridge Kit, 12 runs | 19.842 | 9 | 33 × 33 × 1 in |
| MT-F1637 | Rubber Mat, 18 in × 48 in | 16.314 | 7.4 | 48 × 18 × 1 in |
| MT-F1585 | PVC Roof Sleeper, no holes, 8 ft | 14.33 | 6.5 | 96 × 4 × 4 in |
| MT-F1574 | Adjustable Splice for Bridge Kit, 8 runs | 9.48 | 4.3 | 22 × 22 × 1 in |
| CT-P4 | Rubber Sleeper Pad, 4 in × 10 ft roll | 5.732 | 2.6 | 120 × 4 × 1 in |
| MT-F1573-11 | Adjustable Splice for Bridge Kit, 4 runs | 3.748 | 1.7 | 12 × 12 × 1 in |
6. Layout
- Snap the centerline. Keep the run straight and parallel to the structure where you can, and plan any turns from the assembly drawing. A 90° turn takes two 45° splices and a full diagonal section, which pushes the corner about 5 ft 8 in back from where the two legs would meet (turns).
- Drainage first: don't block or dam drains, scuppers, crickets or valleys, and keep sleepers from trapping ponding water.
- Keep clear of roof edges, hatches, skylights and equipment service clearances. Put a step-over (RT-ST) wherever people need to cross the run.
- Mark every sleeper position. Each 8 ft kit ships with three sleepers, and the assembly drawing gives their placement.
7. Protection layer and sleepers
- Clean the membrane under each sleeper position and lay the approved protection pad, then the sleeper. Sleepers must never sit directly on the membrane unless the roof manufacturer allows it in writing.
- Check that the sleepers are level and fully bearing, with no rocking. Shim only with approved material.
- Don't fasten anything through the membrane. These parts are designed as non-penetrating.
8. Set and splice the tray
- Set each 8 ft section on its sleepers and join sections with the matching adjustable splice: MT-F1573-11 (4-run), MT-F1574 (8-run) or MT-F1597 (12-run). Count one per joint.
- Tighten all hardware to the torque on the assembly drawing and mark each bolt once it's torqued, so you can spot-check later.
- Don't field-cut or drill without ANDREW's written authorization (warranty §8(g)). If a cut is approved, deburr it and touch it up with a zinc-rich coating per ASTM A780.
- At turns, set the splice angle (0–45° each, two per 90°). At curbs and parapets, use the hinged MT-F1703 / MT-F1704 extension kits (0–45° vertical). Neither part comes in the bridge kit. See turns & elevation changes.
9. Place the cables
- Don't put more cables in a kit than its run or hole count. Leave the growth spaces empty and record them.
- Keep every cable above its minimum bend radius (see the cable manufacturer's sheet), especially at entries and transitions.
- For SnapStak cover kits, install the snap-in hangers sized for the cable OD and follow the hanger spacing in the cable/hanger instructions.
- Label both ends of each run, and label the tray at intervals if the owner's standard requires it.
10. Covers and hold-downs
- Install every cover. The bridge kits ship with 12-gauge covers, and the SnapStak kits include hold-down clamps. Use every clamp and fastener the drawing calls for, because loose covers are the first thing a wind event takes.
- Make sure the covers shed water and don't channel it onto cable entries.
11. Building entry
- MT-365G hood entry kit: 49 × 34 × 32 in and 230 lb. The roofing contractor of record makes the curb and opening and flashes them.
- If the roof assembly is fire-rated, firestop the penetration with a listed system.
- Make drip loops on the cables before they go into the hood.
12. Bonding and grounding
- The sleepers insulate the tray, so it floats until it's bonded. Jumper every splice and hinge (NEC 392.60(A) continuity, 10 AWG minimum), and bond each tray end to the roof ring ground, the lightning-protection conductor or the entry ground bar per the owner or carrier standard (AT&T ATT-TP-76416, Motorola R56, TIA-607).
- Ground the coax shields with ANDREW SureGround kits at the antenna end and at the entry ground bar, and at the top and bottom of vertical runs if the standard requires it.
- Use two-hole compression lugs or listed clamps, tinned copper, stainless hardware and antioxidant. No exothermic welds on the roof, and no drilling the tray without ANDREW's OK.
- The full solution, with BOM, tests and RFIs, is on the grounding & bonding page.
13. Inspection and QA
- Walk the whole run: sleepers bearing, pads in place, torque marks present, covers and clamps tight, no membrane damage, drainage clear.
- Get the roofer's inspection and sign-off. Have the AHJ inspect if the permit calls for it.
- Photo-document every sleeper location and joint. Those photos are your evidence if the roof leaks later.
14. Closeout
- As-builts showing the route, sleeper locations, joints, entries and spare capacity.
- The warranty file: packing slips with ship dates, part numbers and quantities, the reseller invoice, and the ownership-transfer notice to ANDREW within 15 days if the material passes from the contractor to the owner.
- The roofer's sign-off letter, the engineer's letter and permit final.
- O&M notes: annual walk-down, check hold-downs after major wind or hail, and keep the walkway paths clear.