Plaster or rendering is a layer added to wall to give straight surface. Plaster edges is the wall weak point, a small force could break the edge. There are several solutions for plaster edges: Regular edge, plaster trim and metal angle. Each of these solutions has advantages and disadvantages. Throughout this topic we will discuss the different solutions for plaster edges.
Plaster Trim or Stop Bead
Plaster trim / stop bead is a rigid angle that fix to walls using steel mesh to Strengthen edges. Also plaster trim gives straight edges as references to get straight surface. The trim have a nice round detail, therefore to keep nice details the trim has to install from tile’s level to ceiling level. Plaster trims are available in different heights, like 2.4 meter and 3 meters this according to producer. The following photo shows a plaster trim installed at a part of the edge only, resulting in a different detail for other parts. Plaster trims are available in different thickness and qualities, thicker trim resist more forces. Also choice plaster trim with wider steel mesh is better to increase trim bonding to wall.
Plaster stop beads are available in different profile and materials like Galvanized steel, Stainless steel, Aluminum, UPVC and vinyl. Metal and steel plaster trims are not recommended because it could rust easy, especially that plaster mortar has lime. lime corrodes metals and accuse rust. Plaster trims available in a certain length (approximately 2.4 – 3 m). Width of the steel mesh vary from 20 to 50 mm, the wider is more expensive but it will connect better to plaster. Good steel angle thickness from 2 to 3 mm in order to resist crushing.
Plaster trim disadvantage is maintenance, if the plaster trim break it’s hard to maintain. It will look ugly after maintenance, the following photo shows the plaster bead after maintenance process. The plaster trim has crushed while moving furniture, and maintaining works done by plaster craftsman then painter continue the works but still look ugly.
Regular edges is by creating the edge out of cement then to smoothing the edge either by small round or diagonal shape. The edge take shape in order to resist small forces. Edges in plaster or any other works like furniture are in place to get daily hits. Since plaster bead is hard to maintain, it’s not recommended installing it. This because when plaster trim broken, this mean plaster craftsman and painter need to fix it. And if there is no plaster trim, painter can fix all the damage by himself.
The lower part of the wall could be round edges while the upper part straight, this will give a nice wall edge details. Also there are many other details for plaster edges. In the past they used to do a stone edges to avoid damage.
Steel angle made from L shape profile, it used as corner protector at edges that could hit by heavy forces like car park and industrial spaces. The L angle available in profile of 3 cm each side and thickness of 5 mm, this allows it to resist heavy forces. Some models can install by cement mortar and other by bolts. Heavy forces will not crush the steel profile but forces will transfer to plaster around the angle, acute damaging at the wall. also some parking corner protectors are made of rubber to prevent transfer forces. The corner protectors can be fixed at the height exposed to hits only, average height between 75 and 100 centimeters.