These days, everyone is looking to save a few dollars wherever they can. I can appreciate this as much as anyone, believe me! However, sometimes “a penny saved” IS NOT “a penny earned”. Shopping out the best price for goods and services is always smart money management; however, when comparing apples to oranges, focusing on the lowest price alone makes it easy to overlook details like quality and long term durability.
We have always believed in the motto “You get what you pay for.” Roofing systems are no different. “Lowest price” is often synonymous with “Lowest quality.”
Single ply roofing systems are becoming popular due to their low initial cost of installation. While it is nice to save a few hundred dollars on a new roof project, it may end up costing much more in the life cycle of the building.
Singly ply systems use large sheets of plastic, rubber, or PVC to cover the roof. The membrane material seems to hold up well in the elements, but has a fundamental flaw in my opinion. Everywhere there is a roof penetration, corner, joint, overlap in material, etc., there is a seam (or sometimes lots of seams) in the material that is typically bonded with some kind of glue. Roofs are subjected to the most extreme weather (wind, rain, burning sun), ALL DAY, EVERY DAY! On a typical single ply roof, there are hundreds, if not thousands of linear feet worth of seams. These area all liabilities for leaks to form when the adhesive fails and the wind lifts the sheets up.

Notice all of the seams visible, just in this section of the roof. All of them are leaks waiting to happen!

This is an excellent example of failing seams. Imagine when its raining and the wind blows into those gaps.
Another issue I have with Singly Ply systems is nearly all of them I’ve seen are not fully adhered to the roof. Generally they are basically nailed down around the edges of parapet walls, with the majority of the material just loosely laying on the roof deck. Wind is constantly working on pulling the glued seams apart, and if a strong wind gets underneath it, the whole sheet can be lifted. I have also seen cases where material has been bunched up around a roof drain, causing the roof to hold water.

Here is another example of a failed seam. Every time this flaps in the wind, more material is lifted up, allowing more rain to enter.

Here is an example of a blocked roof drain. Water has been standing here long enough for weeds to grow over a foot tall!
As with anything, cheaper is rarely the same as better. A single ply roof will likely provide a couple years of service without problems, but it has huge potential for problems over the building’s life. Repairing leaks throughout the years caused by failed seams may end up costing significantly more, not to mention the hassle of dealing with them.
Foam roofs do not have any seams on them whatsoever! Because the foam is applied as a liquid, and part of it’s chemistry is basically gorilla glue, it is fully adhered to the entire roof area! Because of the foam’s rigidity, the entire roof structure is strengthened as it all becomes tied together. The elastomeric coating is also applied as a liquid, and also has excellent adhering properties. This system is self flashing, which means it automatically seals up transitions, penetrations, etc. without any additional flashing mechanisms.

All roof penetrations are coated, as well as the vertical sides and tops of parapet walls. This is part of why our foam roofs are “leak proof”
Furthermore, since the foam itself is virtually watertight, two levels of waterproofing are provided. Even if the coating is punctured, the foam still resists moisture penetration. If the foam is punctured all the way to the roof deck, water is still prevented from traveling under the foam, because it is fully adhered to the roof. Puncture repairs are typically as simple as filling the hole with acrylic caulking. This is why our roofs have a proven track record, even when maintenance is neglected, often lasting decades without any problems.
“If it’s worth doing, it’s worth doing right.” – Jim Cox, Sr.