Tapered Rigid Insulation
Tapered rigid insulation is polyisocyanurate insulation or eps insulation custom manufactured to provide a slope. The first piece may go from 1” high to 1½” high , then the next piece will go from 1½” high to 2” high. Over the course of the roof system, the tapered insulation will create a slope toward the drains, which typically ranges from 1/8” slope (1” down every 8’) to ½” slope (1” down every 2’). A tapered roof system is completely customized for every single roof, from the materials used to how the insulation is laid out. As a result, every piece of insulation needs to go in a precise location, which adds a significant amount of labor to the project.
Tapered rigid insulation is useful on roofs that have excessive water ponding issues, where water cannot find its way to a drain or gutter. This is caused from a variety of issues that are related to the contour of the existing structural deck. Tapered insulation aims to reduce or eliminate the problem by creating a slope toward the drains, which water will follow. While tapered insulation may not stop all ponding, it helps significantly reduce it.
Benefits of Tapered Insulation
- Significantly reduces water ponding.
- Due to the various sizes of insulation used, the R-Value tends to be higher in most locations.
- Follows benefits of product used (EPS, Polyisocyanurate, etc).
Drawbacks of Tapered Insulation
- Significantly higher materials cost, since the system is custom designed and shipped.
- Significantly higher labor cost, since every piece needs to be installed in the correct location.
- Follows drawbacks of product used (EPS, Polyisocyanurate, etc).
Tapered insulation is a great way to get water off a roof. While it won’t stop all ponding completely, it will significantly reduce ponding on most roofs. The big drawback is the increased materials cost, that need to be custom created and shipped, plus the increased labor cost, where each piece needs to be installed in the correct location.