Why DIY Epoxy & PU Coating Projects Fail Within Weeks — And What You Must Know Before You Start

In recent years, epoxy and polyurethane (PU) floor coatings have become increasingly popular due to their seamless finish, durability, and industrial-grade performance. However, a growing number of cases show that non-flooring specialists or DIY attempts to apply these systems often lead to disappointing results — sometimes within just a few weeks.

From peeling and bubbling, to surface discoloration, weak adhesion, and early wear, the root cause is rarely the product — it's almost always the process.

Let’s break down why these failures happen, and what professionals know that most don’t.

1. Improper Surface Preparation

This is the #1 cause of coating failure.
Epoxy and PU systems don’t adhere to dirty, moist, or poorly prepared concrete.
Professionals use mechanical grinding or scarifying to open concrete pores, remove laitance and contaminants, and check for moisture — all before the first drop of coating is applied.

DIY mistake: Simply mopping or acid-washing the floor, thinking it’s “clean enough.”

2. No Moisture Testing or Barrier Layer

Concrete emits moisture, especially in humid environments or on ground-level slabs.
Without moisture testing or a proper Epocem/NWB21 barrier layer, trapped water vapor leads to bubbling, pinholes, and peeling — often within days.

DIY mistake: Applying epoxy or PU directly on a damp slab.

3. Wrong Material for the Application

Not all epoxy or PU coatings are the same.
Some are designed for light-duty, others for chemical exposure or thermal shock.
Using a thin epoxy coating in a heavy forklift zone, or PU SL in a freezer without the correct system spec, leads to premature failure.

DIY mistake: Buying the cheapest or most available product without understanding its intended use.

4. Incorrect Mixing & Application

These materials are chemical reactions in a bucket — if ratios are wrong, pot life exceeded, or application tools used incorrectly, it compromises cure strength, adhesion, and finish.

DIY mistake: Guessing mixing ratios, applying too thick or too thin, or missing recoat windows.

5. No Edge, Joint, or Detail Management

Professionals treat expansion joints, wall coves, drains, slopes, and edges with precision.
Amateurs often ignore these, resulting in cracks, water ingress, and delamination from the weakest spots.

What Flooring Specialists Do Differently:

• Conduct site assessments and recommend the right system

• Use industrial equipment for proper surface prep

• Apply moisture barriers when needed

• Follow strict mixing ratios, temperatures, and curing times

• Handle joints, coves, and edges with skill

• Deliver long-lasting performance backed by experience

In Summary:

Floor coatings look easy — until they go wrong.
And when they do, it costs more to fix than to do it right the first time.

If you're investing in your floor — whether for a warehouse, kitchen, retail space or even a garage — talk to a specialist. The price of professionalism is far lower than the cost of failure.