One of the biggest issues for building owners and facility managers when it comes to replacing roofs is managing HVAC. We know at Flat Roof Company that rooftop units, exhaust fans, and vents keep your building comfortable and your business running, and a new roof shouldn’t cost your business a unit, a fan, or a vent! A design that is carefully planned will ensure that you have the right equipment, tenants are comfortable, and you have a watertight roof. Let’s see what really takes place on your mechanical systems at every step of the job.
Planning and Commercial Roofing HVAC Coordination
Positive results begin before the first tear-off. Successful commercial roofing HVAC coordination depends on establishing a schedule and scope of work in advance between the roofing crew, HVAC provider, and building manager. During the site survey, we map all units, curbs, pipes, conduits, and vents. Curbs are also inspected for condition, equipment ages, and clearances around each unit are inspected.
This is a preliminary assessment of equipment that can remain installed, equipment that must be temporarily disconnected, and equipment that requires lift or reset.
Rooftop HVAC During Roof Replacement: Stay in Place or Lift?
Depending on the roof configuration and the mounting of the equipment, it may be necessary to move the units. When replacing roofs, there are typically two solutions for rooftop HVAC.
Working around the unit. Crews can frequently maintain units when curb conditions are good, and there is adequate clearance available. This is quicker and more economical.
Temporary removal or crane lift. When the curb is rotted, too low, or damaged, or if the units are very old, a crane can be used to lift the curb off to allow proper installation of the roof system underneath. Licensed HVAC techs perform disconnecting and reconnecting.
Commercial Roof Replacement HVAC Considerations
There are two major problems with commercial roof replacement HVAC: height and water. Modern requirements specify curbs to be high enough to enable proper flashing above the final roof surface. Existing curbs are elevated if they are too low in order to securely terminate the membrane. This is a common reason for leaks around mechanical equipment.
Roof Replacement Around HVAC Units
That’s not all that HVAC has up there. Examples of roof replacement mechanical equipment include exhaust fans, gas lines, electrical conduit, satellite dishes, solar arrays, and lightning protection. Gas and electric lines may need to be held at blocks that must be placed on protective pads, preventing the lines from cutting into the new membrane. Loose Lines on the roof can damage the surface over time.
How to Protect Rooftop Equipment During Roofing
Knowing how to protect rooftop equipment during roofing prevents costly damage. Standard safeguards include:
- Dust, debris, and adhesive fumes are prevented from entering or exiting intake/exhaust openings by covering or shielding intake/exhaust openings.
- Applying protective boards or plywood to protect units from impact damage
- Ensuring that hot work, torches, and heavy staging are kept away from refrigerant lines and coils.
- Deactivating or modifying equipment as necessary to exclude contaminants from the building.
This kind of rooftop equipment protection also keeps indoor air quality stable for occupants.
Roof Replacement and Mechanical Equipment Beyond HVAC
HVAC is not the only equipment up there. Roof replacement mechanical equipment can include exhaust fans, gas lines, electrical conduit, satellite dishes, solar arrays, and lightning protection. Gas and electrical lines are often supported on blocks that must be reset on protective pads, so they do not puncture the new membrane. Lines that sit loose on the roof can wear through the surface over time.
Commercial Roof Penetrations and HVAC Flashing
Every pipe, duct, and conduit is a potential leak point. Commercial roof penetrations HVAC teams manage include refrigerant line sets, condensate drains, and duct chases. Each opening needs properly sized boots, pitch pockets, or custom-fabricated flashing, depending on the membrane type, whether TPO, EPDM, PVC, or modified bitumen. Consolidating penetrations where possible reduces the number of future leak points.
Flat Roof HVAC Replacement: Smart Timing
Consider also flat roof HVAC replacement when your roof is being replaced. When units are approaching the end of their usefulness, replacement can be done in conjunction with an open roof, preventing a new roof from being ripped open later. Combining new curbs, new units, and the new membrane in one project minimizes costs and maximizes system life.
Choosing a Commercial Roofing Contractor HVAC Teams Trust
A commercial roofing contractor HVAC specialist will be well-respected for their ability to communicate effectively, have the right insurance and can work with licensed mechanical trades. Inquire regarding their disconnections, crane lifts, curb upgrades, and post-project inspections. We at Flat Roof Company US, plan for your operations to minimize downtime and disruption.
Energy Efficiency After Commercial Roof Replacement
A commercial roof replacement is also a good opportunity to review your building’s overall energy performance. Changes in roof insulation, reflective membrane materials, and air sealing can help reduce heat transfer through the roof and ease the workload on rooftop HVAC systems. Before choosing materials, consider your building’s energy needs, existing insulation, and local climate conditions. Coordinating these improvements during the roofing project can help manage future energy costs while supporting a more comfortable indoor environment. For larger facilities, explore Industrial Roofing solutions designed to meet demanding commercial building requirements.
Frequently Asked Questions
1. Will my HVAC be shut down during a flat roof replacement?
Not always. In many projects, the units proceed while the crew works around the units. Shutdowns are typically short and occur only when disconnections, lifts, and/or dust and fumes must be kept out of the building.
2. Who disconnects and reconnects the HVAC units?
All disconnections and reconnections are done by a licensed HVAC technician in conjunction with the roofing crew.
3. Can the roofer damage my rooftop equipment?
Without precautions, there’s a possibility of damage. The risk is minimized with protective covers, staging, and communication.
4. How are leaks prevented around HVAC curbs?
Curbs are visited, any necessary repairs are completed, curbs are raised if necessary, and they are flashed with the new membrane. Seams and terminations are sealed and checked prior to leaving for sea.
5. Should I replace old HVAC units during a roof replacement?
When equipment is old, it’s sometimes worth it. When the roof is open, replacing it is easier to avoid damage and reduces the number of projects.