Does your flat deck or flat roof need a taper system?


Did you know that the value of the global flat roofing systems market is expected to increase by over ten billion U.S. dollars from 2021 to 2026*? The clean lines, modern aesthetic, and functional versatility give this roofing style undeniable appeal. However, if you reside in a higher elevation area with a snowy climate, flat decks and flat roofs can pose headaches such as snow accumulation, water ponding, and structural stress.

A tapered insulation system, or slope-to-drain system, is a strategy to avoid water damage to your roof by way of directing the water to the edge or internal drain system. These systems take the form of subtle slopes or gradients to facilitate rainwater runoff and snowmelt while preventing ponding and water infiltration.


When would you need a roof taper system?

Not all roofs require a tapering system, but TPO and EPDM roofs require it because they are installed using seams. You need water flowing off of those seams because they are particularly susceptible to weakness with water flow. A taper system helps control the flow and shed precipitation to downspouts, scuppers, and roof drains.

Including a taper system on your roof is especially important for those with homes or buildings in high snow elevation climates, such as Park City and surrounding neighborhoods. Our buildings in Park City must be designed to properly drain large and heavy amounts of precipitation whether it’s rain, snow, or ice. These heavy amounts of precipitation increase the risk of structural overload and potential collapse.

If you anticipate a high volume of water flow for your building, consider a taper system to promote rapid snow/rain shedding and minimize the duration and extent of snow accumulation on your roof.

An example where you might encounter a high volume of water flow is when multiple roofs shed onto a flat deck or flat roof. Any roof with multiple systems intersecting or various wall joints and transition points should have a tapered insulation system.

Roofs such as a ballast or green roof are less likely to need a taper system because they are designed for natural drainage. However, if at any point your ballast or green roof transitions onto a flat roof, we highly recommend working a taper system into your project specifications.

Roofs created using hot applied roofing systems, such as HYDROTECH 6125, are designed to hold water and won’t require any taper. If you want an extra safety precaution, you could add a taper underneath your hot applied roof. These roofing systems have less drainage and insulation issues overall because these are designed to retain water.


Roof Taper System Best Practices

If you decide to install a roof tapering system, while it may cost more money upfront it is more than likely going to save you a lot of cash in the long-term. There are two methods for tapering:

  • – Framers taper it: your general contractor would need to work this into your project specifications.
    – Roofers taper it: a roofer such as Viotell would accomplish this artificially with insulation.

It is extremely important to work with a trusted general contractor due to the depth limitations of a tapering system. You will typically taper a quarter inch per foot, but your general contractor needs to be extra careful because this can limit where windows and doors can go on your building or home. For example, if a door is two inches off the ground, the taper cannot go even 8 feet out past the building.

When planning a more complex project, such as a flat roof, pulling together the right team of experts is critical to success. You’ll need seasoned installers, architects, and general contractors to inspect project site conditions, determine project requirements, and performance objectives. Working with local professionals is crucial, especially when living in high elevation, high precipitation climates. They can include considerations such as snow loads, rainfall intensity, and freeze-thaw cycles.

Architects bring an eye for design to the table, being wary of roof geometry and drainage patterns while maintaining the desired aesthetic. Installers and general contractors can put their heads together for a strategy on material selection, slope calculations, and installation techniques.

As with any roofing, a flat deck or flat roof and especially a taper system, requires periodic maintenance including roof inspections, especially after a large precipitation event. Your team of professionals can assist with establishing a regular maintenance schedule including inspections, cleaning, repairs, and prompt action to clear drains, scuppers, and gutters after storms.



When you’re presented with an “option” while building it can be easy to feel overwhelmed or feel concerned on whether or not the specification is truly necessary. Taper systems play a critical part in ensuring the durability of flat roofs and decks, especially when you live in a climate similar to Park City’s.

We strongly urge you to get an expert’s opinion on whether or not a tapered insulation system is necessary for your project. You can reach out to us using this link to get our skilled craftsmen opinion.





Anthony Ortega, COO & Partner

Anthony Ortega is a dynamic and results-driven executive with a proven track record of fostering growth and innovation. With extensive experience in business operations and high-functioning business acumen, Anthony has consistently demonstrated his ability to integrate and optimize complex business processes.

As the Chief Operating Officer of VIOTELL, Anthony oversees all facets of the company’s operations, finance, fabrication, vendor relationships, and client success. His strategic leadership and expertise in operational excellence have been instrumental in driving the company’s sustained growth and competitive edge.