Roughcast
Roughcast: The Ultimate Exterior Finish Solution
Roughcast is a premium exterior wall finish that provides durability, weather resistance, and aesthetic appeal for both residential and commercial properties. This traditional Scottish finishing technique has evolved with modern materials to offer superior performance in all climates.
Key Product Specifications
- Material Composition: Cement, sand, and crushed stone aggregates
- Application Method: Hand-applied or sprayed
- Drying Time: 24-48 hours (depending on weather conditions)
- Coverage: Approximately 4m² per 25kg bag at 12mm thickness
- Color Options: Available in 15 standard colors, custom colors available
- Expected Lifespan: Minimum 25 years with proper application
| Feature | Description | Benefit |
|---|---|---|
| Weather Resistance | Withstands temperatures from -30°C to +50°C | Perfect for all climate zones |
| Surface Texture | Varied aggregate sizes (2-6mm) | Creates unique visual interest |
| Maintenance | No painting required | Low lifetime maintenance costs |
| Application Thickness | 10-15mm typical | Hides substrate imperfections |
Roughcast Application Process
- Surface preparation: Clean and dampen the substrate
- Apply base coat (if required)
- Mix Roughcast to correct consistency
- Apply Roughcast using trowel or spray equipment
- Finish surface with desired texture
- Allow proper curing time
Roughcast FAQ
Q: How does Roughcast compare to traditional stucco?
A: Roughcast contains larger aggregates than stucco, creating a more textured appearance and better impact resistance. While stucco typically has a smooth finish, Roughcast provides superior water shedding capabilities due to its irregular surface texture.
Q: Can Roughcast be applied over existing finishes?
A: Yes, Roughcast can be applied over most stable substrates including brick, block, and existing render systems. Proper surface preparation is crucial - the surface must be clean, sound, and free from loose material. A bonding agent may be required in some cases.
Q: What maintenance does Roughcast require?
A: Roughcast requires minimal maintenance. An annual inspection is recommended to check for any hairline cracks or damage. Minor repairs can be made with matching material. The surface can be cleaned with low-pressure water washing if necessary, but harsh chemicals should be avoided.
Technical Performance Data
| Test Parameter | Result | Testing Standard |
|---|---|---|
| Compressive Strength | 15 N/mm² | BS EN 1015-11 |
| Flexural Strength | 3.5 N/mm² | BS EN 1015-11 |
| Water Absorption | < 0.5 kg/m²/h0.5 | BS EN 1015-18 |
| Freeze/Thaw Resistance | 50 cycles with no damage | BS EN 1015-21 |
Color Options and Customization
Our standard Roughcast color palette includes natural stone tones ranging from warm buffs to cool grays. Custom colors can be achieved by blending specific pigments during mixing. Samples are available upon request to ensure color matching meets your expectations. The natural aggregate texture means each application has unique visual characteristics even within the same color family.
Roughcast Historical Context
Originally developed in Scotland as "harling," Roughcast was traditionally used on stone buildings to provide weather protection. Modern Roughcast maintains this heritage while incorporating advanced cement technology and graded aggregates for improved performance. The technique gained popularity throughout the UK and Ireland in the 20th century and continues to be specified for both traditional and contemporary architecture.
Roughcast FAQ (Continued)
Q: How long does Roughcast last on a building?
A: Properly applied Roughcast typically lasts 25-40 years. Many historic buildings in Scotland still have their original Roughcast applications after 80+ years. Modern formulations may last even longer due to improved cement technology and additives that enhance durability.
Q: Can Roughcast be repaired if damaged?
A: Yes, Roughcast can be spot-repaired. The key is using matching material and technique to blend the repair with the existing finish. For best results, repairs should be done by experienced applicators who understand how to match both color and texture patterns.
Q: Is Roughcast suitable for all building types?
A: While Roughcast is extremely versatile, it may not be suitable for very lightweight construction or buildings with significant structural movement. Our technical team can advise on specific project requirements. Roughcast is particularly well-suited for traditional masonry construction, concrete frame buildings, and renovation projects.