The Challenges of Re-Roofing a High-Rise

The complexities of re-roofing a high-rise facility are numerous. It’s not the actual roofing trade work that’s challenging – it’s project coordination.

The quality and thoroughness of project planning often determines the success of the re-roof project. A lot of information must be collected upfront. Facilities professionals should be ready to discuss building access, security, work restrictions, and parking with the selected roofing contractor before the project scope is even defined.

Here are some factors you should take into consideration if you’re thinking about a re-roof for your high-rise building…

Start with Communication
Consulting with the city on details such noise ordinance is a necessity. Requirements change from city to city, but permits are usually required for parking, blocking a sidewalk, use of a crane, or street shutdown. If traffic is going to be obstructed, a permit is also needed to reroute vehicles.

It’s also a good idea to alert the local fire chief in advance of the project in case any emergencies or injuries were to occur laborers on the roof or to people walking along the building perimeter.

Additionally, if you’ve leased space to cellular companies, be ready to involve them very early on in the project – they will typically be the ones responsible for lifting and moving cell towers.

Crew Size, Hours, and Speed
In hotel or multifamily towers, roofing crews will most likely need to start working later in the day to avoid disturbances. In an office building, a re-roof project might require nighttime work in order to be less disruptive. Beyond being less of a distraction for daytime tenants, traffic is also less, which makes it easier to block roadways for loading or unloading. The availability of parking spaces for laborers is less of an issue, as is the risk of heat-related illness for laborers.

Evening work, however, requires extensive pre-planning meetings, along with development of a detailed project and communication plan between the facilities manager and roofing contractor. It also requires bright lights that, along with noise, could be offensive to occupants in neighboring buildings. The lighting also results in shadows that can compromise work quality and create a safety hazard for laborers. Additionally, project coordination is critical because workers typically can’t purchase additional supplies or equipment during evening hours.

The quicker your roofing contractor can complete the work, the better (for all involved parties). It may be possible to increase crew size if:

• Crews can work in shifts. One crew can complete noisy tasks at night, and another can do quieter detail work during the day.
• You have more than one roof area. Multiple crews can work simultaneously.
• Access is challenging. A roofing contractor may use an additional crew on the job just for support.

Tear-Off and Loading
Disposing of tear-off and staging and loading materials pose a greater logistical challenge in a metropolitan environment. If street closure is necessary to accomplish this, your contractor will usually subcontract out traffic control to set up necessary detour signs for vehicle rerouting. Job-site postings must be of specific reflective materials and dimensions, so typical postings won’t meet code requirements. How and where they are displayed must be in compliance to minimize exposure to property loss and personal injury claims.

Crews may want to use space within a parking garage or designated loading zone, or along the building perimeter, for staging materials. Which space they use will depend on access and, in some situations, what neighboring property owners will allow. If using a parking garage, smaller trucks must be utilized to clear the eight-foot headway limit.

If space is limited, phased material deliveries will cut down on the amount of ground staging area square footage required. Overloading the roof with materials is usually not feasible because of roof congestion and the higher risk of materials becoming loose and airborne.

Phased deliveries will require extra crane mobilizations unless the crane is brought in and left erected, and then the operator and rigger are scheduled as needed.

Because high-rises don’t usually have a large roof area and loading materials is a logistic challenge, careful planning is necessary to order the right amount of materials and use them entirely so crews don’t have to transport them up and down.

Moving materials either from the roof (i.e. tear-off of an existing roof system) or to the roof (i.e. the new roof system and equipment) can be done any number of ways.

Freight Elevator
Roofing crews can take debris down in a freight elevator and go through a lower-level interior space to dump it. While this may seem like the most economical option, man hours really add up because of how labor-intensive the process can be. When bringing new materials up to the roof via a freight elevator, crews may have to access interior space again if the elevator stops a floor below and doesn’t go all the way to the roof.

Helicopter
Another option is a helicopter or sky crane. Your roofing contractor will subcontract helicopter lifting with a company experienced in the process. Careful planning is required so that a helicopter with proper lifting capacity is used for the load weight and size of the roofing materials. Weather limitations will require flexible scheduling.

Helicopter lifting presents many safety hazards (high winds from aircraft rotors can turn dust and debris into airborne projectiles). Street shutdown may also be necessary to protect the people and property below.

Cranes
Cranes (either mobile or tower) are the most typical way to transport materials to and from the roof. Set up time will be lengthy, though.

When disposing of the existing roof system, a tear-off tarp can be used. These have corner straps that are sewn in and hook to the headache ball. They encapsulate debris and are lightweight; when not in use, they can be folded up for storage. Skip boxes can also transport debris from the roof to the ground using a crane, but they require more space for storage.

Construction Elevator
Unless your facility is a historic building, the best option to move materials may be via a construction elevator, which is set up on the outside of the building. It too has a slow set-up, but is the least disruptive option for building occupants.

Chute
When it comes to disposal of roof tear-off, a chute is the least expensive option – but it requires quite a bit of labor for installation, maintenance, and tear-down. For a multistory chute, debris is brought down a freight elevator, and then disposed of through a lower-story window. A crane is necessary only during chute set-up and tear-down.

Interior Access
Unless the roofing contractor subcontracts the construction of a stair tower platform or construction elevator, their crews will be using the building interior for roof-to-ground egress. Finishes should be protected from potential damage, with plastic covering cover carpet, elevators, etc.

Security is another consideration. Additional guards may be required if roofing crews need entry through multiple locked doors, stairwells, and elevators, or if exterior doors need to be kept open as roofing crews load and unload materials. Work with your roofing contractor to decide if they should hire security personnel to accompany crew members, or if you should alert your own security team that additional resources will be necessary.

Providing advance notice to building security is also required, especially if the roofing crew will be working evenings and weekends, and require access when security staffing is normally light. Special security badges, keys, codes, etc. may also be necessary.

Risk Management
High-rise roofing projects pose unique safety risks that must be addressed. Falling or airborne debris is especially hazardous. The roofing contractor’s project manager should have designated laborers whose sole responsibility encompasses waste management. An intense housekeeping plan must be developed and executed with vigilance. Make sure the roofing contractor you hire has stringent safety policies and enforcement procedures; you can review their safety record for validation.

Catch-fence or windscreen erected around the roof’s perimeter will assist in keeping lightweight material and debris from being blown over the edge. A scaffold tunnel in front of the building can cover the sidewalk to protect pedestrians from debris and/or tools and equipment being knocked over the edge.

High winds are one element of weather that make it unsafe for the roofing crew (and anyone below or in neighboring buildings). The wind speed may be 10 to 50 mph higher on the roof than the ground. Material piles placed on the roof have to be maintained constantly to ensure that the tarps are secure. Hardhats may also be blown over the edge.

Cranes are equipped with wind meters; whenever necessary, the project will be halted to protect workers. Crews can also carry hand-held wind meters or use weather apps on their smart-phones to assist in wind-speed monitoring. High winds can result in unplanned shutdowns; in these cases, precautions need to be taken so the roof is not left exposed to the elements.

Fresh air intakes should be shut off to avoid fumes from roofing adhesives being transferred inside the building.

As with all roofing projects, the contractor’s crew should know which fire exits are available for their use. They should also be familiar with the building’s evacuation plan in case of emergency. Because it may take longer for emergency personnel to respond to a worker who is severely injured on the roof, or falls and is restrained by a fall protection harness, workers should also be trained to administer first aid and CPR, and rescue fellow crew members.

A roofing contractor with experience working on tall, metropolitan buildings is already aware of these challenges; they can be accounted for in advance with proper planning and execution. Safety and crew capacity are equally important criteria on re-roof projects. The right roofing contractor will help you avoid the pitfalls of poor project planning.