Before insulating and cladding a facade, proper surface preparation is essential. This stage determines the durability and performance of the entire facade system. Old walls often have cracks, delamination, weak areas, and contamination that directly affect the adhesion of insulation and finishing tiles. In this article, we explain how to correctly prepare an old facade for insulation and cladding with KORDEKO flexible tiles.
Why You Should Not Insulate “As Is”
A common mistake is installing insulation and cladding over an old facade without proper inspection.
This leads to:
insulation detachment
cracks in the finishing layer
moisture accumulation inside the walls
reduced thermal efficiency
a significantly shorter facade lifespan
Facade preparation is a mandatory step, not a formality.
Step 1. Diagnosing the Facade Condition
Before starting work, assess the following:
presence of cracks (hairline and structural)
peeling old plaster or paint
voids and hollow-sounding areas
signs of moisture, mold, or efflorescence
condition of corners, window reveals, and the plinth
Tip: tapping the wall helps identify weak areas that must be removed.
Step 2. Removing Weak and Delaminated Layers
The following must be removed:
loose or peeling plaster
old paint with poor adhesion
friable and crumbling areas
dirt, grease stains, and dust
The substrate must be solid and stable—otherwise, the entire system will fail.
Step 3. Repairing Cracks and Defects
Depending on the facade condition:
small cracks are opened and filled with repair compounds
deep cracks are reinforced with fiberglass mesh
chips and uneven areas are leveled with adhesive or repair mixes
❗ Important: do not leave cracks “for later”—once insulation is installed, fixing them is impossible.
Step 4. Surface Cleaning
After repairs, the facade must be thoroughly cleaned:
from dust and construction debris
from remnants of old materials
from biological contamination
If necessary, wash the surface with water at moderate pressure and allow it to dry completely.
Step 5. Priming the Walls
Priming is a key preparation step.
Primer selection:
for absorbent substrates — deep-penetration primer
for dense or low-absorption surfaces — adhesion (bonding) primer
Primer functions:
binds residual dust
equalizes surface absorbency
improves adhesive bonding
reduces the risk of delamination
Step 6. Geometry Check and Readiness for Insulation
Before installing insulation, make sure that:
the surface is even
there are no active cracks
the walls are dry
the primer has fully cured
Only then can you proceed with installing insulation (EPS or mineral wool).
Why KORDEKO Flexible Tiles Are Ideal for Renovation Projects