There is an old expression – “if you don’t know where you are going – any road will get you there”. I am going to modify that expression to suit our roof system conversation to – “If you don’t know what kind of roof system that you need, any roof system will do”.

Roof systems are not commodity systems – a roof system is a system and a very important system. A bad roof system can destroy a building. Without a roof, there is no building.

A defective, leaking roof system can defeat, or certainly impede, the functioning of a building. A defective, leaking roof system can consume much management time for the Building Owner – think about the very substantial amount of time and costs that can be consumed by a seriously leaking commercial building like a plaza. In excess of 40 leak service calls at that plaza is a very serious situation.

The overall objective is to eliminate all of the defective leaking roof systems and ensure that the new buildings – provide leak-free performance for the very long term.

A portfolio of buildings with defective, leaking roof systems can overwhelm the property managers and consume management time – so much time and resources can be consumed – at great costs – that the organization will be deterred from moving forward – leaks and complaints can become the primary focus.

Roof System Components

The essential difference between a low quality, weak roof system and a high quality, robust, high performance roof system is the length of service life. Other factors include: maintenance costs and ultimately replacement costs. 

The real cost of a roof system is the Life Cycle Cost of the system – the initial cost plus all other costs over the life of the roof system. The NOW COST or initial cost is just one factor. A high performance roof system that provides a long service life will provide a much lower “Life Cycle Cost” than a roof system with a low NOW COST – the initial cost plus the costs of leak repairs, leak clean-up and repairs, damage to building components, consumption of management time and damage to reputation of the property and the Owner.

I am going to ignore single ply roof systems for the purposes of this conversation. Single ply – one layer – roof membranes are specialty, low cost membranes that are really not applicable to quality properties. Single ply membranes must be perfectly installed – perfection is not of this world, and these membranes present very poor puncture resistance. Punctures lead to leaks and problems.

Below is an enquiry that came to me through my website – this a typical kind of request and situation that I see quite often – (I have redacted any identity items for confidentially). The roof system on this building was picked – based on NOW MONEY – with no consideration for length of service life, leak-free performance, basic good roofing properties or damage to the tenants/occupants and their operations.

Comments: : Hello and good afternoon, We manage the XXXXX building in Kitchener ON, located at XXXXX St. Currently, we are experiencing leaks in a section of the building, and wish to hire an independent roofing consultant to review and provide a report on any deficiencies. The roof was installed in 2017, which makes it very strange that we are having so many leaks (and such severity) within three (3) years of the TPO membrane being installed. The entire membrane spans approximately xxxk SF, but we are interested in a review on a 30k SF section to begin with. If major issues are found, we may expand this investigation to other areas of the building. Please let me know if this is something that you are interested in assisting with, and we will connect you with our on-site staff to review.

The building in question is occupied by very sensitive tenants with very sensitive operations and businesses. This roof system is the wrong roof system for the tenants and building – the costs of the roof system are beginning to mount. Repair costs, management time, tenant compensation are costs that must be added to the NOW MONEY costs of the roof system – the installed roof system will continue to become more expensive as time passes.

“It is always better – read essential – to design a roof system, than to just pick one”

Multi-Ply Roofing

A multi-roof system is reinforced with plies or layers – 2 ply, 3 ply, 4 ply and for some systems more plies – of felt or roofing ply sheets. There are many different types of ply sheets – each possessing different weights, strengths, chemical composition, installation characteristics and physical attributes. Each type of reinforcement, when combined into a roof membrane system will yield different performance characteristics and ultimately, varying lengths of service life.

The oldest and most basic ply sheet is the #15 organic felt – which is blotter paper saturated with asphalt. These ply sheets are typically installed in 4 ply assembly – shingle style – built-up roof membrane with a floodcoat and gravel surfacing. This is a “pick-em” system that is low in NOW COST – but provides a limited service life – approximately 12 years – before the expense of the system begins to rise and increase the overall “Life Cycle Cost”. Organic felts will rot and provide vary poor tensile strength and tolerance to movement.

Fibreglass felts were introduced in the 1980s – to be a stronger, non-rotting substitute for the #15 organic felt. These ply sheets are typically installed in 3 ply assembly – shingle style – built-up roof membrane with a floodcoat and gravel surfacing. This is a “pick-em” system that is low in NOW COST – but provides a limited service life – approximately 12-14 years – before the expense of the system begins to rise and increase the overall “Life Cycle Cost” of the roof system.

Modified bitumen roof systems comprising plies of coated – with SBS rubberized asphalt – ply sheets – are installed in a 2 ply assembly – one complete layer as a base ply and then a top or cap ply. The surfacing is a granulated surface on the cap ply. This is a “pick-em” system that is low in NOW COST – but provides a limited service life – approximately 12-14 years – before the expense of the system begins to rise – the granulated surface degrades and increase the overall “Life Cycle Cost” of the roof system.

Note the decrease in the ply count of each system – the intent is always to reduce the NOW COST of the roof system – but each reduction in the quantity of

materials in the roof system membrane – leads to a reduction in the amount of waterproofing material in the roof system. If a roof system is not waterproof – leaks occur. When the NOW MONEY is the only consideration – it is always a race to the bottom – cheap, cheaper and cheapest. When poor detail design and poor labour are added to a low grade roof system – the result is typically a disaster – please see above.

It is most important to note that once a poor quality roof system is installed – after the continuing leaks can no longer be tolerated – that poor quality roof system must be replaced. Removal of an existing roof system costs money. Removal of an existing roof system in a location with poor access and many other impediments – many people, close spaced buildings, main roads will cost much more money – IF THE REMOVAL AND REPLACEMENT – CAN BE PERFORMED AT ALL. 

For new construction projects, the least expensive time to install a roof system is during the construction process. Once the construction site is removed – all roofing operations automatically become more expensive.

The various discussions over several years – focused on the type of property, the length of service life required, the future use of the building and how the roof system will affect both the asset value and utilization of the property. 

Existing properties that will be redeveloped in the fairly near future – estimated at about 10 years – required a less expensive roof system with a shorter service life. Leak-free performance is always required – but the NOW COST must be less. This type of roof system has been installed. 

For existing properties that are long term holds – major store anchored plazas and other quality properties – a more expensive roof system with a long service life that will provide long term leak-free performance and require minimal maintenance has been installed – these roof systems are essentially install and forget systems – annual inspections for damage and unit problems – but no cost requirements. This is a low life cycle cost situation.

For other properties, the roof system is designed according to the requirements. Design is always a major key consideration for the roof system. Guessing or picking usually leads to big problems.