Wall Putty-Plaster

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 Wall Putty?

Wall putty is a thin finishing layer applied to walls before painting. It fills small holes, smooths the surface, and gives the paint a flat, even base.

It is applied in thin coats (0.5–1.5 mm each). Because the layer is so thin, water retention is critical — the putty loses moisture to the wall and air within minutes if the HPMC is wrong.

2. Two Standards, Two Products

Wall putty is not one product. Two standards define two different materials:

Performance Requirements

Exterior putty needs double the bond strength, plus freeze-thaw and flexibility. That is why it has cement, more RDP, and a hydrophobic agent — things a dry-region interior putty can skip.

3. Interior Putty — Two Types by Climate

Interior putty is not one product. It splits into two types, and the climate decides which one you use. This is the most important distinction in wall putty — get it wrong and the putty fails.

Dry Regions — Quick Lime Putty (No Cement)

In dry regions (northern China, inland areas), quick lime (CaO) is the binder — no cement. Quick lime reacts with water to form calcium hydroxide, which then carbonates over time into a hard, smooth surface. It is white, smooth, and cheap.

Water: 30–35%

Humid Regions — White Cement Putty

In humid regions — southern China south of the Yangtze River, Southeast Asia, coastal tropics — quick lime putty absorbs ambient moisture and loses strength. It fails over time. Do not use quick lime putty there.

Use a white cement-based putty instead. White cement is the binder, quartz sand gives dimensional stability, and a higher RDP dose gives water resistance.

Water: 25–30%

The humid-region interior formula is essentially the exterior putty formula, used indoors. Quick lime cannot survive moisture — white cement is the only safe binder.

4. Exterior Putty Formula (JG/T 157)

Water: 28–32%

What Changes from Interior

Cement becomes the primary binder — 300 kg/t gives the strength and weather resistance exterior walls need.

Quartz sand adds dimensional stability — 200 kg/t reduces shrinkage and resists thermal cycling. A wall in summer sun can hit 60–70°C.

Hydrophobic agent is essential — without S300/S500, rain soaks through the paint into the putty, causing freeze-thaw damage and delamination in winter.

Wood fiber controls cracks — 2 kg/t bridges micro-cracks as they form.

5. Climate Adjustments

6. CHARING Product Recommendations

7. Common Problems and Fixes

8. Common Mistakes to Avoid

1. Using one formula for both interior and exterior. They are two different products. Interior = quick lime + calcium carbonate, no cement. Exterior = cement + quartz sand + hydrophobic agent. One formula cannot do both jobs.

2. Using quick-lime putty in humid regions. Quick-lime putty works only in dry regions. In humid climates — southern China south of the Yangtze River, Southeast Asia, coastal tropics — it absorbs moisture and loses strength. There you must use a white cement-based putty. Dry region = quick lime, humid region = white cement. Do not swap them.

3. Skipping the hydrophobic agent outside. Without it, the first winter's freeze-thaw separates the putty from the wall.

4. Using too little RDP. RDP gives the putty water resistance. Below 12 kg/t in wet areas, the putty softens and peels.

5. Applying too thick. Two thin coats always beat one thick coat. Max 3 mm interior, 3–5 mm exterior.

For technical support, free samples, or help with your putty formula:

Shandong Charing Industry Co., Ltd. 

Email: info@sdcharing.com 

Website: www.sdcharing.com