Selecting the correct plaster bead for your project

Selecting the correct plaster bead for the application will help ensure a high quality professional finish – and there are a few important considerations that will influence the choice of product.

The first must be choosing a plaster bead that is suitable for the intended location and conditions. The three main materials, galvanised steel, stainless steel and PVCu, all have different properties and therefore specific applications.

Galvanised steel beads are designed to be used for internal plasterwork. The zinc coating protects the steel from corrosion but is generally unsuitable for use in exterior areas.

Stainless steel plaster bead products have a natural corrosion resistance and so are suitable for external applications and any interior areas where a higher level of moisture is present or expected.

PVCu (polyvinylchloride unplasticised) beads are recommended for applications with the most challenging environmental conditions. Similar to stainless steel, PVCu plasterbead can be used both for external rendering and internal plastering. PVCu is unaffected by moisture, salt and weathering and is resistant to damage and chemical attack.

In addition to choosing the best material for the job, professionals can also make use of specially designed and engineered beads that will help overcome tricky details, create special effects or simply achieve the highest quality finish. These include:

• Renderstop bead - Designed to deliver a gentle 120˚ gradient at the base of the render. It can be used above doors and windows and at DPC level to allow rainwater to drain clear of the underlying substrate and protect masonry against run-off water that can cause staining.
• Plasterstop bead - Provides clean, neat edges at openings or abutments onto other wall surfaces or ceiling finishes.
• Depth gauge bead - Provides a quick and accurate means of ensuring consistent, minimum plaster depths as plaster is simply ‘ruled off’ to leave the required thickness.
• Architrave bead – used to create a decorative shadow gap effect around doors and above skirting boards. It can also be used to create a clean division between varying wall finishes.
• Movement beads - allows for minor movement between adjoining surfaces resulting from the differential expansion in the underlying substrate or structure. This prevents the surface finish from cracking and ensure a long-lasting, high quality finish.
• Twin nose angle bead - designed for two-coat renders. The first nose acts as a gauge for a scratch coat and the second provides a depth guide for the finishing coat.
• Arch beads - Bends to create curves and arch forms for decorative plaster requirements in thin coat and drylining applications.

When choosing a plaster bead, it is important to remember that not all products are manufactured to the same level of quality and as such, will not perform in the same way. The quality of the product has a key role in achieving a crisp, neat, durable finish to the plaster or render.

For metal products, a stronger, more rigid bead will help deliver a precision finish that is only possible with a true straight edge. A higher quality, more durable bead will also be quicker and easier to install with less wastage as damaged product will not need to be discarded. Therefore, it is recommended that professionals select a product that is manufactured from a heavier gauge of steel. For example, Catnic galvanised and stainless steel beads are manufactured to a gauge that is respectively 11% and 25% above the requirements of both British and European standards.

Similarly, higher quality PVCu beads will make the application quicker and the finish more durable. Our PVCu products have been engineered to meet the needs of professional plasterers. The range is made from exterior grade UV resistant material and features a unique Pro-Grip™ adhesion system. The tiny grooves manufactured into the face of the bead, ribs and undercut perforations increases the surface area, creating a stronger bond with the plaster or render. This speeds up the application and prevents the slippage which is associated with some standard PVCu beads.

Plaster bead can sometimes be viewed as a commodity product and as such the lowest cost option is often the most attractive. However, using the correct type of plastered will not only ensure the best professional finish, it will also ensure durability and help protect from water damage, staining and cracking.