EIFS Mortar-External wall Thermal insulation and finish system

CHARING manufactures HPMC, RDP, and PCE for dry-mix mortar and concrete — supplying high quality products across Southeast Asia, the Middle East, South America and Africa for over a decade. We share what we know.

1. What Is ETICS (EIFS)?

ETICS = External Thermal Insulation Composite System. It is a multi-layer system that wraps a building in insulation to save energy.

In North America it is called EIFS. In Europe and Asia it is ETICS. Same system, different name.

It is one of the most demanding applications for mortar additives. Three layers, three different mortars, three different sets of requirements.

2. Three Layers, Three Jobs

1. Adhesive Mortar → bonds the insulation board to the wall

2. Insulation Board → EPS or mineral wool

3. Base Coat (reinforcing mortar) → covers the board + embeds the glass fiber mesh

4. Primer + Finish Coat → decorative + weather protection

Adhesive Mortar — the "Glue"

Base Coat — the "Armor" (the hard one)

The base coat must:

1.Bond to the EPS board

2.Embed and protect the glass fiber mesh from alkali

3.Resist impact — 3 J standard, 10 J reinforced

4.Absorb very little water — ≤500 g/m²

5.Let water vapor pass (the wall must "breathe")

6.Resist cracking under heat (a dark facade hits 70°C in summer)

Five of these six depend on the additives. Cement and sand alone cannot do this.

3. The Chinese Way — Insulation Can Be a Mortar Too

In Europe and North America, ETICS almost always uses a board (EPS, XPS, or mineral wool) for the insulation layer. The board is glued on, then covered with base coat.

In China that board system is common too. But there is a second, very common Chinese way: the insulation layer itself is a mortar. No board, no glue — you trowel the insulation on in layers.

Two main mortar-based systems:

A. Vitrified microbead insulation mortar - The insulation layer is a dry-mix mortar: cement + hollow vitrified microbeads + additives. - The microbeads are tiny hollow glass spheres. They trap air — that is the insulation. - Fire-safe (inorganic), good bond, durable, no mesh needed. - Needs a thicker layer than a board for the same insulation (the beads are heavier and conduct more heat).

B. EPS granule insulation slurry - The insulation layer is cement + expanded polystyrene granules + additives, troweled on. - Insulates better per thickness than microbeads. Works well on uneven walls. - But the EPS granules are flammable.

Why this matters for additives:

In the board system, additives go into the adhesive and the base coat. In the mortar systems, additives go into the insulation layer itself — and that layer is thick (20–50 mm), so it uses far more HPMC and RDP.

Reference formula — vitrified microbead insulation mortar

(This is a typical reference. The exact ratio depends on the bead grade and the thermal performance required — each company tests its own.)

4. Standards

5. HPMC Selection

Dosage: 1.5–3.0 kg/t.

Hot climate warning: a black south-facing facade in the Middle East can hit 70°C+. In hot climates use HK 100M / HK 200M — heat resistant to 65–70°C. For the harshest heat (dark facades that hit 70°C+), step up to MH (MHEC, 70–75°C).

6. RDP Selection — the Four Options

RDP is the most expensive additive in ETICS. The wrong choice costs money AND performance. Industry test data (3% RDP, standard formula):

The dilemma: EVA gives the best adhesion and impact, but absorbs too much water. Hydrophobic RDP resists water, but fails the impact test.

The answer — System B: EVA + silane hydrophobic powder. It gives both. EVA forms the tough, flexible film. A small dose of silane powder (0.2–0.3%) cuts water absorption from ~1,000 to ~200–400 g/m². This is the industry standard choice.

RDP Dosage vs Impact

Standard grade: 2.0–2.5% (20–25 kg/t)

Reinforced grade (ground floor, public areas): 3.0–3.5% (30–35 kg/t)

Premium (schools, hospitals): 3.5–4.0% (35–40 kg/t)

7. Hydrophobic Agent

Water is ETICS's enemy. A base coat that absorbs water loses bond, freezes and cracks in winter, and traps moisture behind the finish.

Recommended silane dosage: 0.20–0.30% (2–3 kg/t).

8. Reference Formulas

Adhesive Mortar

Base Coat — Standard Grade

Base Coat — Reinforced Grade

9. CHARING Product Recommendations

10. Common Defects and Fixes

11. Common Mistakes to Avoid

1. Saving on RDP. Cutting RDP from 3% to 1.5% halves impact resistance. The system passes visual inspection, then fails the first hailstorm or second winter.

2. Using hydrophobic RDP alone. It resists water but fails the impact test. Always use EVA as the base, add silane powder for water resistance.

3. Ignoring the hydrophobic agent. The best RDP cannot save a base coat that absorbs 900 g/m² of water. The ETICS facades that still look good after 15 years all have hydrophobic base coats.

4. Wrong HPMC gel temperature for hot climates. A dark facade in the Middle East hits 70°C. Regular HPMC gels. Use HK 100M / HK 200M (65–70°C), or MH (70–75°C) for the worst cases.

5. Poor mesh. The additive package cannot compensate for cheap mesh. Use alkali-resistant glass fiber mesh — ≥145 g/m² standard, ≥160 g/m² reinforced.

For technical support, free samples, or help with your ETICS formulation:

Shandong Charing Industry Co., Ltd. 

Email: info@sdcharing.com 

Website: www.sdcharing.com