Case Study: Leaking TPO Roof

Written By Cody Profitt

At Comanche Roofing we take pride in tackling challenging roofing projects that require a high level of attention to detail and craftsmanship.

One recent project involved a complete flat roof replacement due to years of leaks and poor craftsmanship.

Here’s a breakdown of the roofing process and what we discovered along the way.

What is TPO Roofing?

TPO, or Thermoplastic Polyolefin, is a roofing membrane widely used for flat roofs. It’s durable, energy-efficient, and cost-effective.

There are two main ways to install TPO: mechanically adhered (using fasteners) and fully adhered (using adhesive).

While both methods are common, fully adhered systems are far better for residential homes, and this project really highlights those advantages.

Comanche Roofing Team

The Starting Point: Initial Inspection

During the initial inspection, we found a 60-mil mechanically attached TPO system with retrofit drains and plenty of issues:

Ponding Water: There was significant ponding around the drains and in the roof’s corners, mainly due to the lack of proper slope or crickets.

DIY Fixes: The roof had several failed attempts at repair, including; cover-tape over seams, caulking over holes, and duct tape holding the TPO together.

Structural Problems: Someone had tried to create slope using 2X4 wood blocking under the loose-laid TPO, which caused tears and dips in the surface.

Flashing and Coping Issues: Surface-mounted flashing and improperly installed coping with exposed fasteners. These are not only unsightly but also allow water intrusion.

Rot: After tearing into the roof, we found extensive rot, most likely caused by water getting through the failed membrane seams. The moisture spread freely under the loose laid TPO.

Re-Roofing Process

1. Tear-Off To The Deck

We started by tearing everything down to the original plywood deck. The existing roof comprised of:

Plywood base
Modified bitumen layer
Liquid Coating layer
Perlite Board
Mechanically adhered TPO on top

We found multiple sheets of rotting plywood that needed to be replaced, and we removed all the existing drains, flashing, and coping.

2. Slope Correction with Tapered ISO Boards

To fix the ponding water issues, we installed tapered ISO insulation boards. These create a slope that directs water toward the drains.

We also added crickets around the drains to improve water flow and eliminate any pooling.

3. Installing a Fully Adhered TPO System

To prepare the roof, we installed a layer of quarter-inch DensDeck, a fire-resistant board, over the plywood. Then we adhered the TPO membrane to the entire surface with LOW-VOC adhesive, ensuring it wraps up the walls and over the roof edges.

4. Custom Coping and Finishing Touches

The final touches make all the difference. We fabricated custom coping caps with no exposed fasteners, giving the roof a sleek and clean look.

The coping color was requested to complement the house, improving the overall aesthetic.

5. Solar Integration with Pitch Pans

Since the homeowner was adding solar panels, we designed and installed custom pitch pans at all necessary locations.

These waterproof the penetrations where solar mounting hardware is attached, ensuring no future leaks.

The end result

This project turned out great. Here’s what we achieved:

Proper drainage with no ponding water.
A fully adhered TPO system that’s durable, watertight, and visually appealing.
Metal, color-matched coping and flashing that protect the roof and improve its appearance.
A 10-year warranty, giving the homeowner peace of mind.

The homeowner was thrilled with the result, and we couldn’t be prouder of the work our team put into it.

Why Comanche Roofing is the Better Choice

One of the biggest issues with the original roof was the inadequate drainage. Over time, sitting water had penetrated through the poorly welded seams, causing rot and significant damage to the interior. Multiple roofers had failed to fix the roof until Comanche Roofing stepped in with thought out solutions.

If you’re dealing with roof issues or considering an upgrade to TPO, give us a call. At Comanche Roofing, we’re committed to delivering high-quality solutions that stand the test of time.