I've been building rooftops in Chicago for over fifteen years. In that time, I've seen everything: decks that will outlast the buildings they sit on, and decks that should never have been permitted in the first place. The difference comes down to one thing: structural integrity.
Safety isn't a selling point. It's the foundation everything else depends on.
What Your Roof Actually Needs to Support
Most homeowners think about furniture and people. That's the starting point, not the full picture. A properly designed roof deck needs to account for:
- Dead load: The weight of the deck itself—framing, decking material, railings, planters, built-in features
- Live load: People, furniture, snow accumulation (Chicago gets plenty of that)
- Wind load: Chicago isn't called the Windy City for nothing. Uplift forces on a rooftop are significant
- Point loads: Heavy items like hot tubs, outdoor kitchens, or large planters concentrate weight in small areas
Miss any of these calculations, and you're building a problem, not a deck.
Chicago Code Requirements
The Chicago Building Code has specific requirements for roof deck construction. This isn't bureaucratic red tape—these rules exist because rooftops present unique structural challenges.
Every project we build requires:
- Structural engineering analysis signed by a licensed engineer
- Verification that the existing building can handle the additional load
- Proper attachment methods that don't compromise the roof membrane
- Guardrails meeting height and strength requirements
- Fire-rated materials where required
We've filed permits on over 2,000 projects. The process isn't complicated when you know what you're doing. When you don't, you get delays, redesigns, and rejected applications.
The Foundation: Getting It Right
The structural system starts before the first board goes down. It starts with understanding what's below.
Most Chicago buildings weren't designed with roof decks in mind. The existing structure might support a basic deck, or it might need reinforcement. Sometimes the existing joists can't handle the load without additional support. Sometimes they can. The only way to know is to have an engineer evaluate the existing conditions.
We do this evaluation before we start design work. There's no point designing a dream deck if the building can't support it. Better to know upfront what's possible.
Material Selection Matters
Different materials mean different weights. Steel framing is strong but heavy. Aluminum is lighter but more expensive. Wood requires proper treatment and maintenance.
On a rooftop, material selection isn't just about aesthetics. It affects structural requirements, maintenance schedules, and long-term durability. Ipe wood looks beautiful and lasts decades. Composite decking requires less maintenance but behaves differently in Chicago's temperature swings.
We custom-fabricate most of our steel work in our own shop. That means we control the quality, the tolerances, and the timeline. When something needs to fit exactly, we make sure it fits exactly.
Waterproofing: The Hidden Priority
A roof deck sits on top of a roof. That roof is the only thing protecting your building from water damage. Compromise the roof membrane, and you'll have problems that make the deck cost look small.
Proper installation means:
- Penetrations through the roof membrane are minimized and properly flashed
- Support systems distribute weight without creating point loads on the membrane
- Drainage paths remain clear—water needs somewhere to go
- Regular inspection points are built into the design
We work with roofing specialists to ensure the deck installation doesn't void the roof warranty. That coordination matters more than most people realize.
What Happens When It's Done Wrong
I've been called in to assess decks built by others. The problems are usually predictable:
- Inadequate structural support leading to bounce or sag
- Water intrusion from improper penetrations
- Guardrails that don't meet code and can't pass inspection
- Materials that weren't rated for exterior use deteriorating after a few seasons
Fixing these problems costs more than doing it right the first time. Sometimes the only fix is starting over.
Done Right, or Done Twice
There's an old saying in construction: you can pay now or pay later, but you're going to pay. With rooftop structures, that's especially true. The costs of failure—structural problems, water damage, liability issues—far exceed the cost of proper engineering and construction.
We don't cut corners. The structure has to be right. When my guys put something together, it stays together.
If you're considering a roof deck, start with the questions that matter: Can your building support it? What load requirements apply? Who's doing the engineering? Get those answers from people who've done this before. That's where safety starts.