PVCu vs Steel: Choosing the right plaster bead material

Selecting the correct, high quality plaster bead will ensure a neat, crisp, long lasting professional finish, every time. Here's why it's so important.

Plaster beads might be viewed by some as a commodity purchase and as such insufficient care may be taken to select the right product for the job. Yet, using a material that is unsuitable may shorten the life of the plaster or render and present serious issues for the condition of the property.

One of most important factors to consider when choosing plaster bead is the location of the plaster or render and conditions that will be present. This will decide what type of bead should be used and will have a significant impact on whether or not the installation will perform and last as expected. Broadly speaking there are three main materials for plaster bead; galvanised steel, stainless steel and PVCu

Galvanised steel beads are designed to be used for internal plasterwork. The zinc coating protects the steel from corrosion but is generally unsuitable for exterior areas. A number of different galvanised products are available to suit the specific application. Our Catnic range includes angle, depth gauge, movement, architrave and plasterstop beads as well as products for drywall and thin coat plaster.

The corrosion resistance of stainless steel makes it suitable for exterior applications and interior areas of higher moisture. In particular stainless steel beads should be used where a cement-based render is being applied. Here at Catnic, there are standard angle and renderstop beads available alongside plasterstop and movement beads for different widths and plaster depths.

Manufactured from polyvinylchloride unplasticised (PVCu), these beads should be selected for projects situated in the most aggressive climatic conditions. BS EN 13914-1:2005, which covers the design, preparation and application of external rendering and internal plastering, advises the use of stainless steel and PVCu in conditions of high humidity and/or salt laden atmospheres.

PVCu will not corrode, is impact resistant, is unaffected by weathering and resists chemical attack. As such it is versatile and can be used both externally, and internally where a higher level of humidity or moisture is present. The Catnic range features products suitable for a variety of applications including twin nose angle beads 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.

Finally, the quality of the product is crucial to achieve a neat, professional finish and ensure longevity of the plaster or render. When selecting a metal bead, a product manufactured from a heavier gauge of steel is always recommended. The stronger, more rigid bead will help deliver a true straight edge and a precision finish. A strong, straight bead is also faster and easier to install with less wastage. Catnic’s galvanised beads are manufactured to a gauge 11% above the requirements of both British and European standards, while its stainless steel beads exceed these requirements by 25%.

Similarly, with PVCu beads, not all products will perform to the same level. As with our steel beads, Catnic’s high quality PVCu products have been engineered to meet the needs of professional plasterers. The range is exterior grade UV resistant 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 application and prevents the slippage often associated with traditional PVCu beads.

It is also always advisable to check that the plasterbead has a CE marking. This indicates the manufacturer has declared conformity with all safety, health and environmental protection requirements to achieve that CE marking.