Flatness guide for plaster and render galvanized steel 6mm x 2.5m

Welcome to flatness guide FAQ! Here you'll find answers to our most asked questions. Still can't find quite what you're looking for, or have something we should know? Send us an email, we're happy to help!

• Q1: What is a flatness guide for render?

  A1: A flatness guide for render (also called a render guide bead, screed rail, or plaster guide) is a straight profile fixed to a wall before rendering to control:
  - Render thickness
  - Surface flatness
  - Alignment / level
  - Material consumption
  It acts as a depth and leveling reference so the installer can rule off the render perfectly straight using a darby or straight edge.

• Q2: Where are flatness guides used?

  A2: Common applications:
  - External sand & cement render
  - Monocouche render
  - Silicone / acrylic thin coat systems
  - External Wall Insulation (ETICS / EWI)
  - Internal plaster basecoats

• Q3: Do I need guide rails when rendering a wall?

  A3: No — guide rails (flatness guides / screed rails) are not always mandatory, but in most professional rendering they are strongly recommended to achieve consistent thickness and a flat finish.

• Q4: How to set render beads level on a wall?

  A4: Setting render beads (flatness guides / screed rails) level and plumb is the most critical stage of rendering — it determines the final wall flatness and thickness accuracy.
  Before fixing any beads, define the finished wall line. Always start with:
  - External corners
  - Wall ends
  - Window/door reveals
  These become your alignment reference.

• Q5: What is the correct spacing for render guides?

  A5: Render guides (flatness guides / screed rails) are typically spaced 1.2 m to 1.5 m apart, depending on the length of the straight edge (darby / rule) used to level the render.

• Q6: Do you remove render guides after plastering?

  A6: The strips should be removed from the wall before the plaster dries. Note: Do not leave the strips in the wall due to the potential corrosion of galvanized steel in the aggressive chemical environment of gypsum plaster mortars.