If your render is cracking, it's an indication that you've got moisture in it. Here are some helpful hints on how to choose the right render beads for your project.
Render cracking, which can be an unwelcome sight for many homeowners, is caused by several different factors. Structural movement, such as expansion and contraction of the building, can cause hairline cracks in the render. Poor application of the render or rendering in poor weather, shrinkage and drying rates are also factors. If your render dries too fast or too slow, it can lead to defects in your render system.
Another common cause is trapped moisture within your walls. In building maintenance, dampness in the walls is still a problem that many encounters. To help prevent render cracks due to unwanted damp, structural movement and other factors, it’s essential to choose the right render bead for your construction project.
Render beads are vital to plastering and rendering. Typically made of polyvinyl chloride (PVCu) or steel, render beads provide an added layer of protection to the plaster or render to help prevent them from cracking. Render systems without beading can lack reinforcement in such a way that the walls can incur damage. As such, beading offers significant support to the render system, making it an important step in the rendering process. Render beads come in different types, each one suitable for a specific use.
When to Use Each Render Bead Type
1. Bellcast beads
Bellcast beads also referred to as drip beads, are placed within the basecoat layers either above windows or above the DPC level. The DPC (damp-proof course) level is a barrier that can be found at the natural ground floor of a building. Its purpose is to prevent moisture from passing through the building’s floors and walls. Bellcast beads, with their straight, vertical build and perforated wings, provide a clear path for rainwater to drip through. This prevents any moisture from getting trapped within the substrate, which then helps keep the render from cracking.
With the function they serve and the protection they offer against impact, your bellcast beads must then be of the highest quality. They should offer resistance against staining or corrosion, which would then help lengthen their lifespan. Bellcast beads can be used on various types of walls, from timber panels and brick walls to cement boards.
2. Corner beads
Another commonly used render bead in buildings is corner beads, which are used in the corners of your walls. Wall corners are almost always prone to damage and wear and tear due to impact from the environment. Since they jut out from the building, they’re more exposed and vulnerable to damage. These areas are also higher in traffic, making them susceptible to receiving various knocks and bumps. Also known as angle beads, corner beads lend extra reinforcement to all wall corners.
Aside from providing support, corner beads ensure that you get the perfect right-degree-angle look, resulting in an aesthetically pleasing finish. Corner beads are all about smooth, sharp lines and clean-cut edges, which can give your render a professional and appealing appearance. When choosing your angle beads, ensure that you go for those that don’t warp, bend or twist. High-quality beading is durable, protecting your walls for longer.
3. Movement beads
Movement beads are also referred to as expansion beads. These types of beads are installed in movement or expansion joints in buildings. Movement or expansion joints, as their name suggests, are designed to accommodate movement in the structure. They’re able to relieve compression stress from construction materials whenever expansion and contraction occur. To help prevent cracking or chipping in these areas, movement beads can be installed within the base coat layer.
Movement beads can be installed vertically or horizontally over large surface areas to stabilise the render system. A vast stretch of render is considered to be more than 12 meters. Movement beads can reinforce these areas and prevent cracks due to thermal expansion. These types of beads can also be installed in places where different building materials are adjoined to help minimise render cracking.
4. Stop beads
Render stop beads, also sometimes known as stop end beads, are placed around windows and door frames to protect them from impact. They can also be installed against other building claddings, such as soffits, or the underside area of the rafters of your roof. The beads reinforce these areas, specifically the plaster edges, to help prevent any damage to them.
Stop beads produce straight lines for your render and a nice, sharp finish. They can be installed around your windows and doors using render bead adhesive, plaster or mechanical fasteners. To aid in the process of bonding, they have perforated wings. A line of sealant is typically applied on the back edge of the render stop bead to keep moisture from penetrating your walls. When choosing stop beads, consider qualities such as durability and resistance against impacts and the elements.
5. Mesh beads
Meshed beads are beading options for how you can install your render beads. True to their name, mesh beads are already outfitted with mesh. This is for those who don’t have enough time to cut mesh to size separately and then proceed to affix it to the bead before embedding it all within the base coat layer. Meshed beading lets you cut straight to the chase.
The mesh is usually made of durable fibreglass. You can use mesh beads for external wall insulation and added support. The material reinforces the render and walls so that they can accommodate structural movement, thus helping reduce cracks in the render. Mesh beads also offer reinforcement to stress areas such as windows and doors through an overlapping layer of mesh. Moreover, these types of beads can increase the adhesion between your walls and the render system.
Prevent cracks in your render and protect your external walls by choosing the right render beads. At Amaroc, we can help provide you with the right tools to use for your project.