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Case Study: Westlake Roof Leak Repair on an 8-Year-Old Concrete Tile Roof

When an 8-year-old roof is already leaking, the first question any homeowner should ask is not just “where is the water coming in?” but “why is this happening so soon?” On a recent job in The Hammocks of Westlake, near Loxahatchee in Palm Beach County, we found the answer, and it is a systemic issue affecting multiple homes on the same block. This case study walks through how we tracked down a complex leak over a garage, what we found in the attic, and why the original construction method is at the root of the problem.

Quick Summary

BLU Roofing completed a Westlake roof leak repair on an 8-year-old concrete tile roof in The Hammocks of Westlake. The root cause was mechanically fastened (screwed-in) tile installed over a single layer of peel-and-stick underlayment, a system that becomes vulnerable over time as tile movement loosens the screw holes. The repair involved removing rotted plywood, installing new decking, applying CertainTeed SA Granulated cap sheet, reinforcing the valley and return flashings, and re-foaming the tiles. The homeowner called Friday, the proposal was approved Monday, and the repair was completed Wednesday.

Watch Peter Menke walk through the leak diagnosis and repair process on this 8-year-old concrete tile roof in The Hammocks of Westlake.

Project Facts

City Westlake, FL (The Hammocks of Westlake)
Roof Type Concrete Tile
Roof Age 8 Years
Leak Source Underlayment failure at screw penetration, rotted plywood decking
Repair Type Partial repair, new plywood, underlayment, and flashing reinforcement
Products Used CertainTeed SA Granulated cap sheet, roof cement, cotton membrane, ICP polyurethane tile adhesive
Completion Time 1 day (inspected Monday, approved Tuesday, completed Wednesday)

Table of Contents

  1. The Roof Detail: Why This Area Was High-Risk
  2. The Root Cause: A Single-Ply System with Mechanical Fasteners
  3. Finding the Leak: Starting in the Attic
  4. The Repair Process: Step by Step
  5. What Westlake Homeowners Should Know

The Roof Detail: Why This Area Was High-Risk

The section of the roof above the garage was not a simple flat run of tile. It included a bottom valley, a roof-to-wall return flashing, and a cricket, a small peaked structure designed to divert water away from a vertical wall. These are all high-flow water areas, meaning during a South Florida rainstorm, large volumes of water converge in these zones before draining off the roof. Any weakness in the waterproofing system in these areas will be found by water, and it will be found quickly.

When a roof has multiple complex details concentrated in one area, as this garage section did, the margin for error in both the original installation and the long-term performance of the system becomes very small. This is exactly why these zones require extra layers of waterproofing protection, not just the base system used on the open field of the roof.

The Root Cause: A Single-Ply System with Mechanical Fasteners

This roof was built with mechanically fastened (screwed-in) concrete tile installed over a single layer of self-adhered (peel-and-stick) underlayment. In Peter Menke’s experience, this is a system that is more susceptible to premature leaks than two alternative approaches: mechanically fastened tile over a two-ply underlayment system, or foam-set tile over a single-ply system.

Here is why the single-ply, screw-in combination is problematic. Concrete roof tiles are not completely rigid once installed. Over time, as the structure settles, as temperatures fluctuate, and as wind loads are applied during storms, the tiles move slightly. Each time a tile shifts, even a fraction of an inch, the screw that penetrates the only layer of underlayment you have works that hole a little wider. Over 8 years, those screw holes can loosen enough to allow water to migrate underneath the tile and directly through the underlayment.

This is not a theory. This is the fourth or fifth leak on the same block in The Hammocks of Westlake, and the leaks have been in different locations on different roofs. This is not one bad spot on one roof, it is a pattern across an entire subdivision, pointing directly to the original construction method as the systemic cause.

The solution, both for new construction and for repairs, is straightforward. If you are using a single-ply underlayment system, use roof tile adhesive (foam) to set the tiles, not screws. This eliminates the penetration through the underlayment entirely. It is equally important, if not more important, to add a second layer of waterproofing in all high-flow water areas: valleys, returns, crickets, roof-to-wall flashings, around all roof penetrations, and along the perimeter eaves. Doubling the protection in these zones is what separates a roof that lasts 30 years from one that leaks at year 8.

Finding the Leak: Starting in the Attic

Rather than guessing which of the several complex details above the garage was the entry point, we went straight to the attic. Tracing a leak from the inside is the most reliable way to identify the true source, especially when multiple roof details converge in one area. In the attic, we were able to pinpoint exactly where the water was entering and follow the trail back to the roof deck.

What we found confirmed the diagnosis. There was a crack in the underlayment paper at the screw penetration, and directly beneath it, a visible gap in the plywood roof decking. That gap was consistent with a new construction defect, the kind of issue that goes unnoticed for years until water finds it. The combination of the compromised underlayment and the gap in the decking had allowed moisture to sit against the wood long enough to cause rot.

The Repair Process: Step by Step

Once the source was confirmed, the repair followed a precise sequence designed to restore the full waterproofing integrity of the system.

  1. Inspect the attic to trace the leak back to its source on the roof deck.
  2. Carefully remove the concrete roof tiles without breaking any. The homeowner had no spare tiles, so preserving every one was essential.
  3. Remove the old underlayment and damaged roof decking, cutting out the rotted plywood and replacing it with new material.
  4. Reinforce the surrounding waterproofing details, including the bottom of the valleys and the return flashing, to address the high-flow water zones that contributed to the failure.
  5. Install CertainTeed SA Granulated cap sheet underlayment and tie it into the existing roof system using roof cement with reinforcing cotton membrane, creating a seamless, water-tight connection.
  6. Reinstall the roof tiles using ICP two-part polyurethane roof tile adhesive, no new screw penetrations through the fresh underlayment.
  7. Perform a thorough clean up of the work area, leaving the property in better condition than when we arrived.

The homeowner called on a Friday evening. We inspected the roof Monday morning, the proposal was approved Tuesday, and the repair was completed Wednesday.

What Westlake Homeowners Should Know

If you live in The Hammocks of Westlake or a nearby community built with mechanically fastened concrete tile over a single layer of peel-and-stick underlayment, this case study is directly relevant to your home. You do not need to wait for a ceiling stain to take action. A professional roof inspection can identify whether your high-flow water areas have adequate waterproofing protection before a leak develops.

The most important thing to understand is that a leak on a relatively new roof is not necessarily a sign of a catastrophic problem. In many cases, like this one, it is a localized failure that can be repaired surgically, preserving the existing roof system and avoiding a premature full replacement. The key is catching it early, before water has time to cause widespread rot in the decking.

If you have noticed a ceiling stain, experienced a leak after heavy rain, or simply want peace of mind about your roof’s waterproofing system, contact Peter Menke at 561-379-5364 for a professional inspection. BLU Roofing serves Westlake, Loxahatchee, and all of Palm Beach County with honest assessments and repairs that are built to last.


Written By: Peter Menke
Peter Menke is the owner of BLU Roofing and has been serving the South Florida roofing industry for over 6 years. He founded BLU Roofing to provide homeowners with transparent, accurate data grounded in the reality of Florida’s unique climate and building codes, information that is often missing from generic national roofing advice. License #CCC1337285

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