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Article Date: 5th June 2014

Catnic - A Very Broad Range in Bead

Plastic Beads - Plasterers Beads - Render Beads - Steel Lintels

Catnic Plasterers Beads

Of course, most customers will know the Catnic brand name stands for quality in steel lintels, but did you know we also manufacture and supply a broad range of plaster beads?

With everything from stainless steel, galvanised and PVCu we've got a wealth of choice but it's important to ensure you select the right type, according to the project in hand. Failing to do so could result in longer-term problems, as our technical director Richard Price explores here.

However it occurs – whether through poor ventilation, lack of heating or as a result of damp rising by capillary action – damp brings with it many problems. It is not only a serious threat to occupant health, it can also compromise the structural integrity of a building. Before this though, damp is most likely to rear its ugly head in the form of decorative deterioration, causing costly damage.

Where plasterers' beads are present (both internally and for externally rendered areas) there is a risk of failure in damp conditions. Firstly the failure of a bead results in oxidation and the unsightly spread of metal deposits across plasterwork. Secondly, as the bead oxidises in moist conditions, the steel expands, causing the plaster to crack and crumble away. Without intervention at this stage the wall is left vulnerable to further moisture ingress.

Rectifying the problem is time consuming and the fix will never truly replicate the original quality of plastering. Once the damaged plaster has been removed, brush down the area to ensure there is no remaining debris. Now a new bead can be fixed into place and the plaster re-applied. At this stage it is quicker and easier if the repair is like for like, so if the original finish was a skim plaster, jointing materials should be avoided in the repair. It is important to feather the edges carefully, so that the new finish matches up and blends with the existing plaster cleanly. Feathering is preferable to sanding, which could affect the rest of the wall surface.

Generally, where beads fail and the building occupant raises the issue, it is because the wrong material has been selected and installed. There are three types of bead material: galvanised steel, stainless steel and PVCu. While galvanised steel beads can be used externally, they are generally recommended for internal applications only. They can be used externally in moderate conditions providing the exposed sections of the bead are protected with a PVC nosing. Stainless steel beads in turn are more suitable for wet and exterior projects. However, in very moist or extremely aggressive climatic conditions – for example in wet rooms, or projects sited in coastal locations – PVCu beads can also be considered as a durable and long lasting alternative to stainless steel.

Stainless steel should not be used with gypsum plaster.

When shopping for beads, ensure they are also strong. Because beads are generally fixed by nail or plaster dab and a weak, flexible bead will be more difficult to install, less likely to provide a true straight edge and be more susceptible to damage. The gauge is a good indicator of quality. All Catnic's galvanised beads are manufactured from 0.45mm steel and stainless steel beads are manufactured from 0.40mm steel. These exceed the current requirements of BSEN 13658 Parts 1 & 2 by 12.5% and 33% respectively. The result is a robust bead that is both strong and rigid, but lightweight, making it simple to fix in place using standard installation methods.

Often when a bead fails it can go undetected until the problem has escalated and moisture has damaged the plaster and potentially entered the wall. Where properties require refurbishment, the use of well-chosen plasterers' beads can optimise the life of the job, by protecting walls from damage and ensuring a smart, sustainable finish.

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