TPO Roof Life Cycle Costs
In regards to TPO Roofing and life cycle costs, unfortunately this is still unknown. Perhaps not scientifically, but from a flat roof installer perspective it is.
Statistically speaking, we have more data specified to PVC roofs than we do TPO. The reality is that all low slope roof membranes have similar life cycle costs. Yet when you consider them statistically or scientifically they do vary, but all in all, low slope or flat roof membranes all perform quite well.
However, coming from a “roofer’s perspective”, here is what I can tell you; An issue that we as roofers see every day on the roofs, which in truth should be your highest priority in research is the actual installation of the material itself. Numerous building and home owners alike are unaware of the actual process, procedures and potential roof failures due to improper installation of the flat roof.
Another area of concern is the other workers that will attend the roof during construction or after, such as HVAC installers for an HVAC retro-fitter.
Now with the assumption that the contractor is reliable and adheres to all the proper regulation, the reality is that things can happen when a flat roofs are being installed. No flat roofing companies are flawless and has a perfect flat roof installation every-time.
In the offices, we here several conversations about how things can and do go wrong, yet it is how we deal with the problem that separates us from success or failure with other roofing contractors. We see time and time again, people that do not do their proper due diligence because they assume things should just go without incident. Although this is not like buying a car. Hiring a trade is much different.
Of course on the other side of managing roofers or the installation of flat roofs is that there is the pro-active side of things that says there are things that we can do as the roofing contractors before problems arise to assist in a higher probability of a proper roof installation occurring.
Now, in our instance we have done things like institute our industry with an Unconditional Lifetime Guarantee which causes our roofing staff to be more aware of the day-to-day incidents that could occur. It is our responsibility to provide superior roof craftsmanship. This has our staff in a more stringent project path for a flat roof installation quality control system. Ultimately, the craftsmanship itself is what most determines the true cost of your flat roof and not which flat roof membrane or flat roof system was chosen.
Once you get past the issue of the quality of installation for your roof and hiring the right contractor you can then consider which roof membrane to use.
Now to provide some answers specific to your questions, here are some considerations for your low slope roof membrane research;
With respect to traditional low slope roofing (SBS, TPO, PVC, EPDM, BUR) I would recommend using 2 ply SBS modified with complete confidence.
The reason is that with a single ply, you have opportunity for what we call catastrophic Failure. In other words, a hole the size of a quarter in the membrane can cause significant damage to the complete system as the water can travel. With SBS, it is torched down and the opportunity for water migration is less. Here’s one other factor to consider with SBS modified, if you have roof installer that does not install the membrane correctly, this will result in you having significant issues. The deficiency list can be considerable and cost more than replacing the roof in the first place.
Now, You didn’t ask about multi-ply low slope roofing specifically, yet I am going to take the liberty of giving you a couple of thoughts regarding those systems. You are able to get a multi-ply low slope roof like the Tough Roof System that will give you the reflective values you desire. Additionally, you will get the sense of security knowing your roof will have maintained durability. The Tough Roof is a multi-ply built up (BUR) roof system that has layers of bitumen (in this case a synthetic layer in between instead of the traditional felt mats between each layer) and on the top, Tough Roof uses white elastomeric roof coating which contributes to the reflective component.
The other option you have in these newer systems is a multi-ply liquid rubber system which is VOC free, completely environmentally friendly and you can cover it with an acrylic reflective top coat. The system is a proprietary system that includes 2-4 layers of liquid rubber with a synthetic fabric between layers of built up and with an optional top coat of acrylic reflective roof coating. Of all the systems you can get, this particular system is most environmentally friendly, it is bullet proof like the built up roofs, and it can be as reflective as you choose.
So ultimately your choices are; traditional 3-4 layer built up roofing (Tar and Gravel) which is 3-4 layers of tar with tar felt paper in between, then the 2 ply modified bitumen which is torched down, the single ply roofing (EPDM, TPO, PVC) which is mechanically fastened, fully adhered, or ballasted, and then the newer type of built up roof like the Tough Roof which is 3-4 ply of tar with synthetic fabric between the layers with an elastomeric top coat for reflectivity and the newer built up liquid rubber systems from GRS that are 2-4 layers of built up liquid rubber with a synthetic fabric between the layers with the option of a reflective top coat of acrylic elastomeric roof coating.
From least expensive to most expensive the roof membrane systems typically go from least expensive to most costly as follows; Spray Foam, EPDM, TPO, PVC, 2 Ply, GRS Liquid Rubber BUR, Traditional BUR, Tough Roof. However, it is important to note when considering the cost of a flat roof replacement or a low slope roof system two things. First, the cost difference between flat roof systems as you go from one to the next is small in comparison to expected life cycle cost planning. For example, EPDM roofing is moderately more costly than Spray Foam, and PVC moderately more cost than TPO and on and on as you go through each system. Yet the important consideration is the cost of the roof over a period of time. A properly installed Tar and Gravel roof or properly installed 2 Ply SBS Torch on Roof will likely last much longer than EPDM, TPO, or even PVC – “likely” has a number of considerations…. weather, application, service workers on the roof, etc. And a Liquid Rubber Built Up Roof and the Tough Roof built up systems have almost unlimited life cycle as they both come with maintenance agreements to renew the top reflective layer of elastomeric coating.