The evolution of flat roofing over the past 150 years in North America has seen the extinction of wood and coal-fired kettles being used to heat up tar.
This was replaced by fuel-fed burners in more modern incarnations of the tar kettle; and with the invention of pumpers, steaming asphalt could then be transported up many stories as a result of this “advanced” technology in the flat roofing industry.
The methods used in heating up hot asphalt have resulted in many a burn injury; just ask any kettle man.
Seasoned kettle men can also relay the tales of the “woof “sound, and the plumes of grey smoke that immediately precede an overheated kettle blowing its lid off. Both flames and hot spewing asphalt, climbing thirty feet in the air. This was the experience of this young apprentice several decades ago.
I certainly concluded that day some thirty-five years ago, that hot roofing was indeed a dangerous sport.
In the early eighties, the use of torch-applied bitumen roofing began to take hold in the Toronto area.
Old time roofers were still skeptical that these one ply applications of rubber rolls (anyone remember U.S. Intec Brai™ or Dibiten™); would last in comparison to the tried and true four ply organic felt roof systems which had been a stable for more than one hundred years.
These products caught on, and many shingle roofers began to enter the flat roofing arena by offering these torch applied goods to their customers. Many progressive flat roofing contractors also began offering these single ply APP modified bitumen assemblies, which were supposed to be painted with a silver reflective paint once the application had cured.
Single ply mod- bit assemblies quickly transitioned into two ply modified bitumen assemblies with the introduction of SBS products that were better suited to cold climates and related colder weather applications. No longer was there a need to paint these ”rubber roofs”, as the newer mods had a ceramic granule surfaced cap sheet which designed to guard against UV degradation and also provided a nicer finished appearance and colour options.
As a result; torch application two ply mod bit assemblies have transitioned over the past forty years to become the most widely used flat roofing systems today, hands down in our region of North America.
These hearty proven systems (when installed properly) represent a proven and light weight waterproofing option for both commercial and residential flat roofs and low slope applications, but are not without their own potential for danger and peril.
Fire is the obvious risk when dealing with any open flame torch on roofing. Even the most experienced torch mechanics sooner or later have a fire ignite; which much of the time can simply be extinguished with a roof located fire extinguisher.
The hidden danger results from the smouldering which can occur beneath the roof, and is not detected before the work day is over. It only takes sawdust beneath the roof deck, or dry timber to have a fire erupt after smouldering beneath the roof for many hours over night.
This can result even though a conscientious contractor utilizes heat detection guns and leaves a technician posted for fire watch after a day’s worth of torching effort.
The fact is much of the damage resulting from a roof fire (fairly minor event) can be corrected easily enough. It is the water damage which results in costly damage from fire-fighting efforts, that causes the most damage to interior finishes and goods.
Of course the potential for loss or injury to occupants is the roofing contractor’s worst nightmare under such scenarios, so heaven forbid it results in a major fire.
So here is the thing; it doesn’t matter as a roofing contractor that you have performed over a thousand successfully executed torch applied projects, it is the one that catches fire, that can be the ruin of a good business, and worse the guilt, if someone is injured as a result.
As a legitimate roofing contractor, you must also have attention on the subject of flat roofing insurance.
If you are a shingle contractor dabbling in flats, you had best have proper insurance coverage and endorsements on the policy or you are playing Russian roulette. As a property owner you are playing double jeopardy if you hire such a firm or individual that does not have such insurance.
There will be those industry readers reviewing this article who may dismiss these concerns in their mind, but regardless; insurers today are taking a serious look at this issue. The fact is, there are a very limited number of insurers that supply hot applied and torch applied insurance policies to roofing contractors across North America.
As a legitimate roofing contractor, you know you already pay huge for insurance and also commensurate with the volume of business that you do. The reality today is that if you have a torch related fire, future premiums may become unaffordable or you may lose the ability to renew such insurance.
There will always be a place for torch applied roofing, but likely those roof tops that have non- combustible roof substrates such as metal or concrete will be the qualifier moving forward in the history of flat roofing.
The good news in 2020 is that we have cold applied, two ply modified bitumen membrane systems, such as made available by manufacturer’s such as Soprema™; who are world leaders in all aspects of flat roofing goods manufacturing.
Cold applied assemblies provide all of the virtues of torch applied mod bit assemblies; and even offer a few other advantages. Such cold applied systems are low odour and utilize a process of welding with hot air as opposed to an open flame.
As a result cold applied mod bit systems are often preferred on projects such as schools, hospitals , long term care facilities and retirement homes. For residential applications, cold applied systems are a much safer choice.
Another advantage of cold applied assemblies involves the fact that proper adhesion of the material rolls is achieved by using an adhesive applied at an even rate of coverage. The required seam details are completed using a robotic hot air welder which provides uniformly bonded seams using a consistent temperature.
By comparison; torch application and quality relies solely on the torch technician’s ability to maintain a consistent degree of flame across the surface of the roll to insure a proper field bond, and when completing overlapping seams; has the ability to complete a uniform bleed out of molten bitumen.
The over-heating, or burning of scrim can then be related to premature product failure.
Another advantage of cold applied modified bitumen is that the runway needed to train installers is less than what is required to develop a competent torch technician. It can take literally hundreds of hours of practice to become a fluid torch applicator, and one who can complete detail work in a professional manner.
Cold applied modified bitumen has a slight disadvantage in that it is not recommended to be installed below minus ten degrees, unlike torch methods; but who really wants to work in such temperatures anyway unless it is absolutely necessary.
The fact is, cold applied modified bitumen is not new. Engineers and contractors have elected to use such methodology on everything from heritage restorations to complex industrial projects for well over a decade.
There are also “ peel and stick” modified bitumen options available which can be used in a base ply form, and or as a membrane flashing detail to cover parapets and inner wall details. This represents another option which limits the use of an open flame.
There are also other flameless options for flat roofing which are primarily used in the commercial and industrial realm. Single ply technology as supplied by Firestone™; include TPO, EPDM and PVC.
Single ply systems regardless of their particular chemical formulations and composition, essentially are an engineered sheet good which relies on mechanical attachment and can be either loose laid, fully adhered using adhesive or ballasted .
Single ply flat roofing systems tend to be generally more cost effective on larger roof real estate when there are wide open areas free of appliances and roof details.
Essentially the consumer today has many safe choices when it comes to addressing flat roof requirements. In fact, those people responsible for making decisions in circumstances such as cooperative housing, condominiums , long term care,manufacturing facilities, and even residential homes; need to request such options for limiting their liability and aiding a greener planet.
To learn more about cold applied modified bitumen systems, single ply assemblies, commercial and industrial roofing, repair and maintenance; visit: www.avenueroadroofing.com and check us out on YOYTUBE™.