Why Surface Preparation is the Key to Long-Lasting PU Waterproofing

Peter Kai
Oct 11
2 min read

The Hidden Foundation of Every Successful Waterproofing System

When property owners in the Philippines choose polyurethane (PU) waterproofing for their roof decks or balconies, most think the magic lies in the coating itself. But here’s the truth: even the best waterproofing system can fail without proper surface preparation.

At Everdry Waterproofing, we’ve seen it all—peeling membranes, trapped moisture, and premature leaks—all caused by neglected preparation.

1️⃣ Why Surface Preparation Matters - surface preparation PU waterproofing

Surface preparation ensures that the PU membrane properly bonds to the concrete substrate. If the surface is dusty, oily, or uneven, the coating will not adhere well—leading to delamination, blistering, and water seepage after just a few months.

Think of surface prep as the “primer” for your building’s protection. It determines whether your waterproofing will last 2 years or 20 years.

2️⃣ The Step-by-Step Process of Proper Surface Preparation

A. Cleaning and Inspection

All dirt, laitance, and loose materials must be removed using grinders, brushes, and blowers.Any oil, grease, or efflorescence is washed away using a degreasing solution or mild acid wash. Through years of learning and expertise, Everdry Waterproofing Experts know precisely when a surface has achieved the right profile before applying the first coat.

B. Crack and Void Treatment

At Everdry Waterproofing, we include crack and joint treatment as a vital step in our PU waterproofing system. All cracks and honeycombs are sealed with PU sealant or epoxy filler to block hidden leak paths, and movement joints are reinforced with backer rods and flexible sealants for lasting flexibility and performance.

C. Surface Profiling

Smooth concrete is roughened or ground to improve adhesion. If the roof deck has ponding issues, slope correction is done to ensure proper water drainage.

D. Priming

A PU-compatible primer is applied to lock the surface pores and enhance bonding between the concrete and membrane. Drying time typically ranges from 2 to 4 hours before applying the first PU coat.

3️⃣ Common Problems When Surface Prep is Skipped

Problem	Result	Why It Happens
Blistering or bubbles	Leaks form beneath coating	Moisture trapped before application
Peeling or delamination	Coating lifts off	Dusty, smooth, or oily substrate
Uneven coating	Shortened lifespan	Poor slope or surface not leveled

Even top-grade PU waterproofing products can fail if applied over a poorly prepared surface.

4️⃣ The Everdry Standard

Our waterproofing process follows international-grade surface preparation standards, ensuring:

100% adhesion between PU and concrete.
Smooth yet roughened surface texture for coating grip.
Zero trapped moisture before application.
Long-term durability, even under direct sunlight and heavy rain.

We also conduct moisture testing and surface inspection before any waterproofing work begins.

5️⃣ Why Choose PU Waterproofing

PU (polyurethane) systems are flexible, UV-resistant, and ideal for roof decks, balconies, and parapet walls.They can bridge hairline cracks and provide a seamless, watertight membrane that lasts for years — if and only if the surface is prepared right.

Before applying any PU waterproofing system, remember:

Proper surface preparation isn’t just the first step — it’s the foundation of waterproofing success.