Rooftop platforms & crossovers. On the roof, not through it.

Where they fit

The roof is a work area. It rarely gets built like one.

Every rooftop with mechanical equipment on it is a place people have to go — to change filters, pull a coil, read a meter, clear a drain. On most buildings the route to that equipment is a walk across the membrane, a step over a duct, and a scramble up a parapet where the roof steps between levels. That's how membranes get damaged and how people get hurt.

A rooftop platform system fixes both problems at once: it gives a defined, guarded walking route at a level surface, and it keeps foot traffic and equipment load off the membrane. The engineering question is almost never the platform itself — it's how the load gets to the building without putting holes in the roof.

Configurations

• Roof crossover stairs — stairs and a landing connecting two roof levels where the roof steps up or down. The most common single request, and the one with no catalogue answer, because the level change is whatever your building happens to be.
• Crossover platforms — stair-up, platform-over, stair-down units that bridge ductwork, piping, conduit runs, or a parapet without stepping on any of it.
• Service platforms around equipment — a guarded working deck built around and between mechanical units, with the manufacturer's service clearances designed in. See equipment-support platforms.
• Rooftop walkways — elevated runs connecting a roof hatch or access stair to the equipment, keeping traffic on steel instead of membrane.
• Stair towers — exterior stair access up to a roof level, tied into the building or free-standing on its own footings.

The load path: three ways onto a roof

This is the decision that drives the whole design, and it should be settled before anything is drawn:

• Fully ballasted (non-penetrating). The system is held by weight, not fasteners — nothing passes through the roof assembly, and the roof warranty is untouched. Requires the structure below to accept the added dead load, and requires the ballast to be engineered for wind uplift and lateral stability, not guessed.
• Curb- or sleeper-mounted. Bearing onto existing curbs or new sleepers, with flashing detailed by the roofer. Fewer penetrations than direct anchoring, but still a roofing scope.
• Structurally anchored. Load carried through the roof into joists, beams, or columns. The most efficient structurally, the most invasive practically — and the option a roof warranty holder will have the strongest opinion about.

We size and detail all three. On buildings with an active roof warranty — which is most municipal and institutional buildings — the answer is almost always the first one. The full explanation is in rooftop steel with no roof penetrations.

Detail decisions

• Ballast engineering — per-base ballast sized against wind uplift and the overturning lever arm, with a safety factor, not a rule of thumb. Load is shared between bases through the connected frame.
• Membrane protection — bearing pads under every base so the only thing touching the roof is a compatible, non-abrasive surface. Membrane type is confirmed with the roofer before fabrication.
• Distributed dead load — a ballasted system is heavy by design, so the roof structure gets checked for the added load. On an older building this is the item that can change the approach.
• Drainage — bases and walkways detailed so they don't dam water or block a drain path. Ponding under a platform is an ice hazard and a membrane problem.
• Demountability — a bolted, ballasted system can be taken apart and moved when the equipment changes or the roof gets replaced. Anchored steel cannot.
• Service clearances — coil pull, filter access, and panel swing come from the equipment submittal and set the platform footprint before the walkway does.

Typical parameters

• Walking width30" – 48" clear typical
• Live loadmaintenance rating, project-specific
• Level changesite-measured; no stock rise
• Guards42" with toe board
• Treadsgrip-strut or bar-grate (sheds ice)
• Attachmentballasted / curb-mounted / anchored
• Finishhot-dip galvanized (exterior default)
• Deliverydesign, fabricate & install — one contract

Turnkey, including the parts nobody wants to coordinate

Most rooftop work is bought as a single scope for a reason: it touches structural engineering, the roofing warranty holder, the mechanical contractor, and a crane or hoist plan, and splitting those across vendors is how schedules slip. We take it as one contract — site measure, structural design, stamped drawings, fabrication in our Ontario shop, and install by our own crew — and we coordinate the roofer and the crane rather than leaving the seams to you. It's the same delivery model described on the process page, and it's how we work with municipal and institutional buyers who need a single point of responsibility on a tender.