Flat Roof Problems: Nail Pops and Building Movement on Tar & Gravel and TPO Roofs

13 minutes ago3 min read

Flat roofs, especially tar and gravel (BUR) and TPO roofing systems, are widely used for their durability and cost-effectiveness. However, over time, building movement, thermal expansion, and improper fastening can lead to serious issues—nail pops, hidden leaks, and structural damage.

At Roof Repair Today, we’ve repaired dozens of these roofs and have seen firsthand how these problems develop. The biggest challenge? Tar and gravel roofs hide issues under layers of gravel, making it difficult to detect problems until severe damage occurs. Sometimes, a full section of the roof needs to be redone to ensure long-term reliability.

Let’s break down why these issues happen and how they can be prevented and repaired.

Why Do Nail Pops and Building Movement Damage Flat Roofs?

1. Building Movement

Over time, buildings naturally shift due to:

Settling – Foundations adjust and settle, causing slight structural movement.
Wind & Vibrations – High winds and external vibrations (from machinery, traffic, or nearby construction) create minor shifts in the structure.
Structural Load Changes – Additional weight from HVAC units, rooftop installations, or snow accumulation can impact movement.

This shifting can cause fasteners (nails and screws) to loosen, leading to nail pops that create holes in the roofing material.

2. Thermal Expansion & Contraction

Roofing materials expand in heat and contract in cold temperatures. When this happens repeatedly:

Older BUR systems may not flex properly, causing nails to push up.
TPO membranes can wrinkle or pull away from fasteners.
Movement can weaken adhesive bonds, leading to water infiltration.

This is a common issue in New Mexico’s extreme climate, where temperature swings between day and night put stress on flat roofs.

3. Aging & Deterioration

If the underlying BUR or TPO system is aging, moisture can get trapped, weakening the structure and making fasteners more prone to loosening and popping. This deterioration increases the risk of hidden leaks, especially in tar and gravel roofs where gravel covers the surface, making damage hard to see.

4. Poor Fastening or Installation Issues

Sometimes, the problem starts with improper installation:

❌ Nails or screws were not secured tightly enough.

❌ The roofing system was not properly adhered to the deck.

❌ Materials were not designed to handle long-term expansion and contraction.

When fasteners are loose, even minor movement can cause them to pop, creating small holes where water can seep in and cause leaks.

Why Tar and Gravel Roofs Are the Biggest Concern

The most difficult issue with tar and gravel roofs is that gravel hides nail pops and other damage. Water can leak through these small holes for months or even years before it becomes visible inside the building.

By the time the leak is noticeable, the underlying roof section may be severely compromised, requiring a complete section replacement instead of a simple repair.

That’s why regular roof inspections are critical—especially after extreme weather or seasonal temperature changes.

How We Fix & Prevent These Issues

At Roof Repair Today, we know how to properly diagnose and repair these issues before they become major problems. Our solutions include:

Reinforced Roofing Systems – Using fabric-reinforced silicone applications strengthens the roof against movement and expansion.
Sealing Penetrations Before Coating – Ensuring all nail pops, fastener holes, and weak spots are sealed before applying silicone or TPO membranes.
Routine Inspections – Checking for early signs of movement-related damage before they cause significant leaks.
Proper Fastener & Adhesive Techniques – Securing nails and screws properly and using expansion-resistant adhesives to prevent movement-related damage.