Corner bead on render systems

Corner bead is used on all external corners on render-only systems. It is a pretty important component of the render/external wall insulation system and in this blog we look at what it is, where it is used and why!

What is corner bead?

Corner bead tends to be made from rigid PVC, moulded into a 90-degree angle. The PVC has lots of holes within it so when it is embedded with the adhesive, the adhesive can travel through it and completely immerse the corner bead, helping to hold it in place. Sometimes corner bead comes with mesh wings attached to the rigid PVC; these can be covered with adhesive, again helping to keep the corner bead in place.

At EWI Store we offer several different types of corner bead, depending on the situation and the type of render being used. Our main corner bead types are either:

• For use in thin coat render systems (the corner bead is completely buried within the thin cost render system). This comes with or without mesh wings attached to the PVC.

• For use in monocouche scratch render systems (bead protrudes out of the render on the corner).

What is the reason for using corner bead?

Corner bead is used in render systems for 2 main reasons:

• Corner bead reinforces and protects external corners – this includes around windows and doors, as well as at the corner of the property.

• Corner bead provides a nice sharp finish when rendering.

Corner bead adds an extra layer of protection for external corners, which often take a lot of knocks. The layer of impact-resistant plastic provided by corner bead reinforces stress points and allows render to be flexible without cracking. It is amazing the number of knocks that the corners of buildings take. Using the corner bead ensures that even if knocks do occur, then the system will be able to withstand the impact.

Corner bead is also used to provide sharp 90-degree angles on the corners of buildings. Trying to free form a 90-degree angle is difficult and although some renders decide not to use corner beads, we would never advise it! The corner bead is relatively cheap in the scheme of things and so it makes sense to use them to ensure you can get that perfect angle on the property!
How do you embed corner bead?

If using a thin coat render system, then the corner bead is embedded using either the EWI-220 Adhesive or the EWI-225 Premium Adhesive. It is completely embedded within the adhesive/basecoat layer, but be sure not to wrap the basecoat mesh around the corner – instead run the mesh up to the rigid PVC moulded plastic. This ensures you don’t ‘round’ the corner when installing the corner bead.

With monocouche scratch render, the scratch render is taken up to the corner of the bead, but the bead still shows through the render. You can therefore get different colours of monocouche scratch render corner bead – get in touch for options!

Corner bead makes your life easier during installation, increases the lifespan of the system and gives a better looking final result – so make sure to use it when rendering or installing EWI systems!