Outer valve
The valve patch sits on the outside of the bag. Fast to fill, easy to inspect, and the most common choice for putty powder and tile adhesive in 20–25 kg.
Application · Building Materials
Valve bags for putty powder, tile adhesive and dry mortar
Multi-wall paper sacks with inner, outer or ultrasonic valves for 20–50 kg dry powders — built to survive drop tests, container shipping and tall pallets.
What We Supply
A bag designed around your filling spout
Putty powder, tile adhesive and mortar are abrasive, dusty and heavy. They are filled fast, stacked high and shipped far. The three decisions that matter most are the film layer, the perforation and the valve form.
- 2-paper-1-film and 3-paper-1-film structures
- Inner valve, outer valve and ultrasonic valve options
- Perforated plies for fast de-aeration during filling
- Inner and outer bottom reinforcement for 20–50 kg loads
- Multi-language flexo printing in 1–8 colours
Specifications
Common building material bag structures
Typical configurations for dry-mix producers. Final size is set from your fill weight and product bulk density.
| Structure | Typical size | Fill weight | Best for |
|---|---|---|---|
| 2-paper-1-film, outer valve | 39.5 × 35 × 10.5 cm | 20 kg | Tile adhesive and fine fillers on fast lines |
| 2-paper-1-film, outer valve | 45 × 40 × 11 cm | 25 kg | Putty powder and wall filler |
| 3-paper-1-film, reinforced bottom | 50 × 45 × 12 cm | 40 kg | Dry mortar and heavier mineral blends |
| 3-paper-1-film, reinforced bottom | 56 × 48 × 12.5 cm | 50 kg | Mortar, sand blends and long-distance export |
| Ultrasonic valve, heat-sealed | Built to your fill weight | 20–25 kg | Dust-sensitive lines and clean pallet presentation |
Valve Options
Which valve form suits your line?
Inner valve
The valve is formed inside the bag mouth. It protects the valve during transport and gives a cleaner finished appearance on pallets.
Ultrasonic valve
Heat-sealed after filling for a tight, dust-controlled closure. Preferred where the product is fine, valuable or health-sensitive.
Failure Points
The three reasons building material bags break
When a dry-mix producer comes to us with a leaking or bursting bag, it is almost always one of these.
1
Not enough plies for the drop height
A 50 kg bag dropped 1.2 m onto a pallet edge needs more plies and a reinforced bottom than a 20 kg bag filled gently.
2
No de-aeration
Without perforated plies the bag traps air, does not sit flat, and stacks lean — which is where most seam failures start.
3
Moisture and long container transit
Paper alone will not hold back humidity for a six-week sea voyage. The film layer and the way it is bonded to the plies decide whether the powder stays free-flowing.
FAQ
Putty powder valve bag questions
Which valve type is best for putty powder?
For high-speed lines with dust control requirements, an outer valve or ultrasonic valve is usually preferred. Paper and inner valves remain common for slower lines and manual handling.
Why are perforated plies important?
Perforations let air escape while the powder is blown in. Without them the bag puffs up, does not sit flat on the pallet and loses stacking stability.
2-paper-1-film or 3-paper-1-film?
Both combine paper plies with a film layer for moisture resistance. 2-paper-1-film suits standard 20–25 kg fills; 3-paper-1-film adds strength for heavier loads and longer transit.
What size for 20 kg or 25 kg?
It depends on bulk density. Bags for 20–50 kg building powders commonly run from about 39.5 × 35 × 10.5 cm up to 56 × 48 × 12.5 cm. We confirm the exact size from your fill weight and product density.
Can the bags be printed in two languages?
Yes. Multi-language print is standard for building material bags — brand artwork, mixing instructions, warnings and barcodes — in 1 to 8 flexographic colours.
Related reading: valve bag vs open-mouth bag, all paper bag structures, certifications.
Send your dry-mix bag specification
Tell us what you pack, the fill weight, your filling line and destination port. We will advise the structure and quote within one working day.