Hot and humid summers pose a significant challenge for putty application. Improper practices can lead to various wall “skin diseases,” compromising the final finish. What common issues might you encounter, and how can you solve them? This article provides the answers.
1. Dusting / Delamination
Phenomenon: After drying, the surface feels powdery, and dust comes off on touch. In severe cases, delamination occurs between two putty layers or between the putty and the substrate.
Root Cause: In hot, dry conditions, water evaporates too fast, preventing proper curing and causing dusting. If the base coat is weak/powdery and the top coat is too hard/dries too fast, delamination can occur.
Solution: In hot, dry, or windy weather, dampen the substrate (no standing water) before application. Ensure compaction during troweling and manage drying time appropriately.
Solution: In hot, dry, or windy weather, dampen the substrate (no standing water) before application. Ensure compaction during troweling and manage drying time appropriately.
- Interior Walls: Polishing timing is crucial. Polish immediately after the surface water sheen disappears. Practice shows polishing should be done per 1-2 m² area.
- Exterior Walls: After surface drying, sand appropriately and perform sufficient water spray curing. Two or more curing cycles are more effective.
- Storage: Protect from moisture. Store in a cool, dry place with packaging intact.
2. Overly Rapid Drying
Phenomenon: Mixed putty dries too quickly in the bucket, making application difficult. It loses water rapidly after application, preventing proper troweling or causing premature drying.
Root Cause: High ambient temperature, low humidity, excessive ventilation, or direct sunlight accelerate the reaction of compounds in the putty.
Solution: Prevention is key. Avoid application during high-temperature periods and direct sunlight. Control ventilation on site. If the substrate is overly dry and absorbs water too quickly, apply a primer or pre-moisten the surface before applying the coating.
Solution: Prevention is key. Avoid application during high-temperature periods and direct sunlight. Control ventilation on site. If the substrate is overly dry and absorbs water too quickly, apply a primer or pre-moisten the surface before applying the coating.
3. Curling / Peeling During Application
Phenomenon: The putty film lifts or peels off in flakes during troweling or finishing.
Root Cause: Excessively dry substrate surface or high on-site temperature.
Solution: Ensure the substrate is moist during application and avoid high-temperature periods, such as midday. For areas that are already peeling, remove the putty, apply a sealing agent, and reapply it.
Solution: Ensure the substrate is moist during application and avoid high-temperature periods, such as midday. For areas that are already peeling, remove the putty, apply a sealing agent, and reapply it.
4. Bubbling
Phenomenon: Bubbles appear during or after the application of putty.
Root Cause: High summer temperatures cause the substrate to dry too quickly, leading to the formation of a surface skin that traps moisture/air beneath. Alternatively, moisture in the putty expands and isn’t absorbed, creating bubbles.
Solution: Mix the putty thoroughly and apply it within suitable temperature ranges.
Solution: Mix the putty thoroughly and apply it within suitable temperature ranges.
For large bubbled areas, break small bubbles with a scraper knife and reapply suitable putty.
- After initial mixing, let the putty sit for ~10 minutes, then re-mix with a mechanical mixer before application.
- If bubbles appear in the second or finish coat, break them with a trowel before the water sheen disappears.
- For very rough walls, use a coarse-grade putty for the base coat.
- In extremely dry, windy, or bright conditions, lightly moisten the wall with clean water and wait until no surface water remains before applying the product.
5. Color Difference & Yellowing
Phenomenon: Uneven color or localized yellowing on the wall after drying.
Root Cause: Impurities such as rust in the mixing water, material variations between different batches, and insufficient treatment of efflorescence on old walls.
Solution: Use clean water for mixing. Use products from the same batch for the same wall. Apply an anti-alkali primer/sealer on old walls.
Solution: Use clean water for mixing. Use products from the same batch for the same wall. Apply an anti-alkali primer/sealer on old walls.
6.Insufficient Adhesion
Phenomenon: Poor bonding between the putty layer and the substrate, leading to hollowing or detachment.
Root Cause: Dust on the substrate not being cleaned, an overly smooth surface, or excessively high temperatures affecting the film formation of the adhesive.
Solution: Thoroughly remove dust and oil stains from the substrate. Roughen smooth surfaces or apply an interface treatment. Avoid application when the apparent temperature exceeds 35°C.
Solution: Thoroughly remove dust and oil stains from the substrate. Roughen smooth surfaces or apply an interface treatment. Avoid application when the apparent temperature exceeds 35°C.
7. Cracking
Phenomenon: Various cracks appear in the putty layer: linear, T-shaped, mesh shape, irregular short cracks, local crazing, corner cracks with vertical short lines, etc.
Root Cause: Applying too thick a coat or overly rapid drying, causing differential shrinkage. Specifics include:
- Application on an insufficiently dry substrate (moisture content >10%).
- Applying the top coat before the base coat is fully dry causes uneven shrinkage.
- Applying hard putty over incompletely dried patching/filling materials.
- Excessive thickness leads to different drying rates inside and out.
Solution:
- Ensure the building structure is stable before application.
- Carefully pre-treat cracks and joints in cement-sand mortar substrates.
- Severely cracked putty must be scraped off and re-applied.
- Minor shrinkage cracks usually don’t affect subsequent work.
In summary, applying putty in summer is challenging due to moisture imbalances caused by high temperatures and dry conditions. To improve application tolerance and film quality, add specialized additives to the putty mixture.
Celotech has prepared two putty formula tables and additive tables for your selection. Please review these tables and select the most appropriate solutions for your needs.
Chart 1: Recommended Formulation For Wall Putty
Chart 2: Recommended Additives For Wall Putty
| Product | Character | Grade | Cement based | Neutral | Lime based | Gypsum based | Putty paste |
| Cellulose ether | Medium viscosity | Celopro® ME40M | ●● | ●●● | ●● | ● | |
| Medium viscosity | Celopro® MT3025 | ●●● | ●● | ● | |||
| Medium viscosity | Celopro® MT3360 | ●●● | ●● | ● | |||
| Medium viscosity | Celopro® MT7033 | ●●● | |||||
| Medium viscosity | Celopro® MT4030 | ●●● | |||||
| Delayed solubility | Celopro®MK70MSL | ●●● | |||||
| Medium viscosity | Celopro® ME50M | ●●● | ●● | ●●● | ●● | ||
| High viscosity | Celopro® MK70M | ●●● | ●● | ●● | ●● | ||
| RDP | Rigid(Vac/E) | Vinabond® N511 | ●● | ●● | |||
| Neutral (Vac/E) | Vinabond® N515 | ●●● | ● | ||||
| Flexible(Vac/E) | Vinabond® N516 | ●●● | ● | ||||
| Pregelatinized starch | Based on corn | Prestar® 1027 | ●●● | ||||
| Based on cassava | Prestar® 1105 | ●●● | |||||
| Starch ether | HPS | Stargel® ST300 | ●●● | ● | ●● | ●● | |
| Cellulose fiber | 300um,white | Celofier® CF300W | ●● | ●● | ●● | ●● | |
| Repellent agent | Silicone based | Aquago® WP200 | ●● |
