Shuttering oil, also known as formwork oil or mould release agent, is a high-quality mineral oil applied to the inner surface of formwork before concreting. It plays a vital role in construction by facilitating smooth removal of formwork, enhancing the durability of the formwork, and improving the final appearance of concrete. This article provides a detailed look at the uses, types, and application of shuttering oil, along with guidelines for selecting the right product for your construction needs.
Uses of Shuttering Oil
Shuttering oil serves multiple purposes that make it indispensable in construction:
- Prevents Sticking of Formwork
By creating a barrier between the concrete and formwork, shuttering oil ensures the formwork doesn’t stick to the concrete, allowing for easy removal once the concrete hardens. - Protects Formwork
Applying shuttering oil protects the formwork, enabling it to be reused several times and reducing overall construction costs. - Improves Surface Finish
Shuttering oil helps achieve a smooth, defect-free concrete surface with minimal blemishes or air pockets. - Prevents Water Absorption in Wooden Formwork
For wooden formwork, shuttering oil prevents the wood from absorbing water from the concrete, preserving its structural integrity. - Reduces Water Leakage
By sealing the formwork, shuttering oil minimizes water leakage during the curing process, which ensures better concrete hydration. - Prevents Corrosion in Steel Formwork
Shuttering oil contains rust inhibitors that protect steel formwork from corrosion, thereby extending its lifespan.
Performance Based on Formwork Type
The performance of shuttering oil depends largely on the type of formwork being used:
- Wooden Formwork
- Requires oils that can penetrate slightly into the wood and leave a greasy but non-slippery surface.
- Ideal oils include pale, paraffin-based mineral oils or oil-phase emulsions.
- Care must be taken to avoid leaving free oil on the surface, which can affect the concrete finish.
- Steel Formwork
- Needs water-free oils containing rust inhibitors to prevent corrosion.
- Oils designed for wooden formwork are not suitable for steel, emphasizing the need to choose the right product for the material in use.
Types of Shuttering Oil
Shuttering oil is available in several types, each suited to specific applications:
- De-Shuttering Oil (DSO)
- Description: A water-based mould release agent.
- Application: Applied as a light film using a brush or sprayer. Excess oil should be drained before it dries, as pooling can cause surface defects in the concrete.
- Advantages:
- Economical.
- Non-toxic and non-hazardous.
- Compatible with all types of concrete formworks.
- Reduces cleaning time before reuse.
- Provides a uniform concrete texture and color.
- De-Shuttering Oil Emulsion (DSOE)
- Description: A ready-to-use oil that does not require dilution.
- Features: Offers convenience and efficiency, making it suitable for quick applications.
- De-Shuttering Oil Concentrate (DSOC)
- Description: A dilutable mould release agent.
- Usage: Requires mixing with water or another solvent before application, providing flexibility in use.
Application Guidelines
Proper application of shuttering oil is crucial for optimal performance:
- Surface Preparation
Ensure the formwork surface is clean and free from previous impurities before applying shuttering oil. - Application Tools
Use spray guns, rollers, or brushes to apply the oil evenly over the formwork surface. - Excess Oil Removal
Avoid over-application or pooling of oil, as dried excess can cause surface defects such as retardation marks. - First-Time Formwork Use
Apply three coats of shuttering oil or use barrier paints to create a hard-wearing surface on new formwork, ensuring durability. - Reinforcement Protection
To prevent contamination of reinforcement bars, shuttering oil should be applied before erecting the formwork.
Additional Tips
- Barrier Paints: Using barrier paints extends the life of the formwork by providing a durable protective layer.
- Regular Maintenance: Reapply shuttering oil consistently and inspect formwork for any damage or wear to ensure consistent performance.
Conclusion
Shuttering oil is an essential component in modern construction, providing numerous benefits such as ease of formwork removal, protection of formwork materials, and improved concrete finishing. Selecting the right type of shuttering oil based on the formwork material is critical for achieving the best results. By following proper application techniques and maintenance practices, you can maximize the efficiency and lifespan of both the formwork and the oil, contributing to a smoother, more cost-effective construction process.