Reading beyond the roof plan

By Cotney Consulting Group.

The more fluent you become in construction drawings, the fewer surprises you’ll face and the more profitable and professional your work becomes.

Ask any seasoned professional, and they’ll tell you the blueprint set is more than just a roof plan. Yet far too many roofing contractors only skim the surface. They’ll glance at the roof page, maybe double-check the dimensions and call it a day. However, construction drawings are layered with critical information, much of which can make or break a job if overlooked. When contractors understand how to read the complete drawing set, not just the pages labeled “roof,” they move from installer to problem-solver. And that difference shows up in everything from profit margins to customer satisfaction. 

The real pros know that the details that matter most to a roofing scope might be hiding in architectural sections, structural information, mechanical plans or even plumbing riser diagrams. Miss a pipe penetration or misread a tapered insulation layout, and you’re left scrambling during install or worse, submitting change orders that eat into trust. And let’s not even talk about bid-day mistakes. Estimators who don’t know where to look can miss hundreds of thousands in material, labor and logistics over a year. It all comes back to how well you know the plans. 

Take something as basic as a site plan. Many in the roofing trade dismiss it, assuming it’s only for grading or landscaping. But we’ve seen cases where accessory structures, such as storage sheds, mechanical yards, dumpster enclosures or even larger outbuildings, only appear on the site plan. Not the roof page. If those aren’t caught in the takeoff, you’re either absorbing extra scope or backing into the GC asking for a change order that makes you look like you didn’t do your homework. 

Or consider demolition plans. These are more than just a box to check. If a project includes tie-ins, partial tear-offs or structural alterations, you must know what’s staying and going. One missed section of the roof deck or a removed structural wall can disrupt your sequencing or create downstream problems for equipment placement, tie-in details and scheduling. 

Architectural drawings are where we gather most of the information. Elevations can help you verify the slope, identify parapet conditions or catch material transitions. Section details reveal insulation heights, coping requirements or structural heights that aren’t visible on the roof plan. Even the notes and schedules on architectural pages may call out finishes or edge conditions that affect flashing, termination bars or tie-in strategy. Don’t forget to look at interior sections too; those can sometimes show shaft walls or penthouse transitions that impact your scope, even if they’re not apparent from a top-down view. 

Mechanical and HVAC plans deserve just as much attention. Rooftop units, exhaust fans, intake ducts and pipe stanchions are frequently missed when the estimator or foreman doesn’t flip through the mechanical set. And it’s not just about flashing these penetrations, it’s about how they affect layout, material cuts, insulation and staging. The mechanical schedule often includes unit sizes and curb details, which you’ll need if you’re building custom curbs or flashing to specific elevations. We’ve also seen cases where units shown on mechanical pages weren’t on the roof plan. Imagine showing up with a clean layout only to find out half your field needs to be cut around units that were there the whole time. 

Plumbing and electrical drawings matter too, especially regarding rooftop penetrations. Drain sizes, riser locations, lightning protection or conduit runs often fall outside what the roof plan covers. A thorough review of the plumbing set can prevent layout conflicts or help you pre-plan for prefab curbs, pitch pockets or additional boots. On the electrical side, you might find callouts for junction boxes or satellite dishes that require early coordination. These aren’t always caught in preconstruction meetings; being the contractor who brings them up first can go a long way with the GC. 

At the end of the day, construction drawings are maps and like any map, they’re only helpful if you read all the directions, not just the street you’re traveling. Roofing contractors who take the time to learn the whole language of blueprints aren’t just protecting themselves; they’re adding value to the entire project team. When you can ask the right questions early, catch conflicts before they happen and price your work accurately from day one, you become more than a sub; you become a strategic partner. 

This competitive advantage is too often underutilized for contractors looking to level up. Train your estimators and field leads on how to navigate the drawing set. Sit down as a team and review a complete plan set before you ever pick up the phone to call in a bid. Don’t wait until problems show up in the field to backtrack through the drawings for the answer. Read them like a general contractor would, and you’ll earn the reputation of someone who sees the big picture and delivers results. 

The more fluent you become in construction drawings, the fewer surprises you’ll face and the more profitable and professional your work becomes. That’s the real power of knowing your plans inside and out.