Tile Roof Waterproofing: What Every Gainesville Homeowner Should Know

Tile roofs offer exceptional longevity, beauty, and durability—but only when installed with proper waterproofing. In Gainesville, Georgia and surrounding areas like Flowery Branch and Dahlonega, our mix of heat, humidity, and storm seasons makes waterproofing even more critical. Let’s break down exactly what that means for your tile roof.

Why Waterproofing Matters for Tile Roofs

Clay and concrete tiles are water-shedding—not waterproof. That means the true barrier protecting your home from leaks is the waterproofing layer underneath the tiles, not the tiles themselves.

When tile roof systems are improperly waterproofed, here’s what can happen:

• Water seeps through tile joints and cracks

• Underlayment degrades faster from moisture

• Leaks appear around chimneys, valleys, and flashings

• Mold and wood rot form beneath the roof deck

What a Proper Tile Roof Waterproofing System Includes

Here’s what we install and inspect as part of a quality tile roof waterproofing system:

✅ 1. Roof Deck Preparation

• We use 15/32" plywood or better as required by code for structural support.

• The deck must be dry, clean, and smooth before underlayment is applied.

✅ 2. Underlayment

This is your primary waterproofing defense beneath the tiles.

We typically install:

• ASTM D226 Type II (No. 30 felt) or ASTM D4869 Type IV

• Double layers for lower slopes (3:12–4:12)

• Self-adhering membrane (ASTM D1970) for valleys, penetrations, and eaves to prevent ice damming and wind-driven rain intrusion.

The underlayment must:

• Lap at least 2” horizontally and 6” vertically

• Turn up 6" at walls and roof transitions

• Extend 24" inside the exterior wall at eaves

"In many instances, the underlayment is considered an integral part of the tile roof system." — NRCA

✅ 3. Flashing Details

We install and inspect:

• Metal flashing (minimum 26 gauge, G90 galvanized) at valleys, chimneys, and roof-to-wall connections

• Pipe jacks sealed at both deck and tile level

• Z-bar or reglet for walls and skylights

✅ 4. Optional Enhancements

• Slip sheets for high-profile tiles to allow movement without tearing underlayment

• Eave risers and bird stops to prevent pest intrusion

Common Waterproofing Failures We See (and Fix)

• Torn or missing underlayment at valleys

• Improper lap joints or turned-down edges

• Flashing that’s rusted, missing, or installed without enough overlap

• Underlayment installed over wet decking

We’ve seen it all—and repaired it all throughout Cumming, Buford, and Silver City. If your home’s tile roof is over 15 years old or you've had past repairs, it may be time for a full inspection.

FAQs About Tile Roof Waterproofing

How long does waterproofing last under a tile roof?
Underlayment can last 20–30 years depending on exposure and ventilation. Premium self-adhered membranes can last even longer.

Can I install new tile over the old underlayment?
Only if the underlayment is in excellent condition—which is rare. In most cases, full replacement is the right call to prevent future leaks.

What’s the best waterproofing for heavy rain and storms?
We recommend a two-ply underlayment system with self-adhered membrane in valleys and eaves for Gainesville’s frequent storms.

Do you need waterproofing on steep-slope tile roofs?
Yes. Regardless of slope, all tile roofs require waterproof underlayment—tiles alone won’t stop water intrusion.

At L&L Roofing and Construction, we believe in doing the right thing, not just the easy thing. Every tile roof project we take on—whether repair or full replacement—gets treated with care, craftsmanship, and code-compliant installation.

If you’re unsure about your tile roof’s waterproofing, give us a call. Let’s protect what matters most—your home and family.

Need a Tile Roof Inspection or Waterproofing Quote?
Call us at (770) 874-0372 or visit llroofs.com