Re-Roofing (Overlay) vs. Tear-Off in Jacksonville: What Florida Code Allows

# Re-Roofing (Overlay) vs. Tear-Off in Jacksonville: What Florida Code Allows

When Jacksonville homeowners start getting bids for a new roof, they sometimes hear two very different approaches from contractors: "tear-off and replace" vs. "overlay" (installing new shingles over the existing ones). The cost difference can be significant — overlays cost less because they eliminate the tear-off and disposal labor.

But Florida's building code has specific requirements that limit when an overlay is permitted, and there are practical reasons why tear-off is almost always the better long-term choice in Jacksonville's climate.

## What Florida Building Code Says About Overlays

The Florida Building Code (FBC), Section 706, addresses existing roofing:

**One existing layer**: If your Jacksonville home currently has one layer of roofing material, a second layer (overlay) is generally permitted under Florida code, subject to conditions.

**Two existing layers**: If your home already has two layers of roofing material, any replacement must be a complete tear-off down to the decking. Florida code does not permit a third layer. Period.

**The 25% rule**: If more than 25% of the existing roof surface requires replacement, the work must bring the entire roof into compliance with current code — which in many cases means a full tear-off and new system. This is the provision that often surprises homeowners who thought they needed only a partial repair.

**Hurricane exposure areas**: In Jacksonville's wind exposure zone, there are additional requirements about how overlays must be fastened and what underlayment must be used, even in a permitted overlay scenario.

## What Contractors Must Do in an Overlay Installation

Even when an overlay is code-permitted in Jacksonville, Florida code requires: - The existing roofing must be in acceptable condition (no rotted or wet decking beneath) - Damaged or missing shingles in the existing layer must be repaired or removed before the overlay - New underlayment must be installed according to current FBC requirements (not simply relying on the old underlayment beneath) - The new shingles must be fastened to meet current Jacksonville wind zone requirements — which means longer fasteners to reach through both layers into the decking

A contractor who simply nails new shingles over the old ones without addressing these requirements is not complying with Florida code.

## The Practical Problems With Overlays in Jacksonville

Even when an overlay is technically permitted, there are compelling reasons why most experienced Jacksonville roofing contractors recommend tear-off:

### Hidden Decking Problems

When you overlay without tearing off, you lose the opportunity to inspect and repair the decking. In Jacksonville, where moisture intrusion is common, a significant percentage of homes have at least some decking damage that would be discovered and repaired during a tear-off. An overlay locks that damage in place, where it continues to deteriorate — often causing premature failure of the new roof.

### Shingle Warranty Complications

Most major shingle manufacturers (GAF, Certainteed, Owens Corning) have specific requirements about overlay installations that may limit or void the warranty. If the overlay does not meet manufacturer specifications, you may have a roof with no effective warranty coverage.

For Jacksonville homeowners who want the full manufacturer warranty — including algae and wind coverage — tear-off is typically required by the warranty terms.

### Weight Accumulation

Two layers of asphalt shingles typically add up to 5-7 pounds per square foot. While most Jacksonville homes can structurally support this, older homes with roof framing that is already near its design load may have concerns. An engineer assessment may be warranted for older homes before approving an overlay.

### Reduced Lifespan

The new shingles in an overlay installation sit on a surface that is not perfectly flat — the old shingles below create an irregular substrate. This can cause the new shingles to wear unevenly and can create areas where the new shingles bridge over the irregular surface below rather than lying flat. This affects longevity and can affect wind resistance performance.

Industry data suggests overlay roofs typically last 80-85% as long as tear-off installations under similar conditions.

### Heat Retention

Two layers of roofing material trap more heat than one layer, contributing to higher attic temperatures — already a significant issue in Jacksonville's climate. A tear-off installation with a new ventilation assessment and proper underlayment performs better thermally.

## When Does an Overlay Make Sense in Jacksonville?

Overlays in Jacksonville are reasonable only when all of these conditions are true: 1. There is currently only one layer of roofing material 2. The existing roofing and underlying decking are in genuinely good condition (inspected, not assumed) 3. Budget is a primary constraint and the homeowner understands the trade-offs 4. The home will be sold in the near future (and the disclosure to buyers is handled honestly)

Even in these cases, we typically recommend tear-off to Jacksonville homeowners who plan to remain in the home for more than 5-10 years. The long-term performance difference is meaningful.

## What to Expect in a Jacksonville Roofing Contract

A reputable Jacksonville roofing contractor's contract should: - Clearly state whether the project is a tear-off or overlay - If tear-off: specify decking inspection and replacement pricing - If overlay: specify the underlayment and fastener requirements that meet both FBC and manufacturer warranty requirements - Include permit language

Be cautious of any contractor who proposes an overlay without first inspecting your current roof condition and confirming it meets the conditions for a code-compliant overlay installation.

At Next Level Roofing Contractors, our default recommendation for Jacksonville roof replacements is a full tear-off, and we explain the reasoning thoroughly so homeowners can make an informed decision. Contact us for a free estimate and honest assessment.